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K Unit guideForces and their effects

© Harcourt Education Ltd 2003 Catalyst 1 This worksheet may have been altered from the original on the CD-ROM. Sheet 1 of 1

Where this unit fits in Prior learningThis unit builds on:ideas introduced in unit 4E Friction and unit 6E Forces in action in the key stage 2 Scheme of Work.

The concepts in this unit are: • force and its measurement • balanced and unbalanced forces• the difference between mass and weight • forces in relation to changes in motion• friction, air resistance, upthrust and weight • speed (a qualitative approach with calculation

only for the more able pupils).

This unit leads onto: This unit lays the foundation for unit 9J Gravity and space, unit 9K Speeding up and unit 9LPressure and moments.

This unit relates to: design and technology scheme of work.

Framework yearly teaching objectives – ForcesRecognise that a force has both magnitude and direction and use this to: • identify the directions in which forces act • describe situations in which forces are balanced.Describe situations in which forces are unbalanced and use this idea to explain a change in: • the shape of an object • the direction of a moving object • the speed of a moving object.Explore the forces acting on stationary objects.Describe the forces acting on objects moving at constant speed.Distinguish between mass and weight, giving examples.Describe some ways of reducing friction between an object and a solid surface and some situations in which friction is useful.

Expectations from the QCA Scheme of WorkAt the end of this unit …

… most pupils will … … some pupils will not have madeso much progress and will …

… some pupils will have progressed furtherand will …

in terms of scientific enquiry NC Programme of Study Sc1 1a, b, c; 2d, f, g, h, i, j, k, l, m

• make predictions about friction• test these and relate their findings to scientific

knowledge• make suitably precise observations• use these to plot graphs• investigate friction, identifying and controlling

key factors• discuss how Archimedes checked the purity of a

gold crown by measuring its volume bydisplacement.

• make predictions about friction• test these and identify patterns in

their results• with help plot graphs of their

results• make relevant observations using

appropriate equipment.

• explain how they made a fair comparison in theirinvestigation of friction

• interpret their results on floating, using knowledgeof balanced forces to explain conclusions

• explain how the scales they chose and lines theydrew on graphs enabled them to show dataeffectively

• discuss how Archimedes checked the purity of agold crown by measuring its volume bydisplacement and relate this to density.

in terms of physical processes NC Programme of Study Sc4 2a, b, c, d

• identify directions in which forces act anddescribe situations in which forces are balanced

• distinguish between mass and weight, givingexamples

• describe some ways of reducing friction andsome situations in which friction is useful

• describe what is meant by speed.

• identify forces, e.g. friction,upthrust and weight

• recognise that friction opposesmotion, upthrust pushes upwardsand weight pulls downwards

• compare speeds qualitatively.

• show how forces can combine to give a resultanteffect that depends on both the sizes anddirections of the forces

• describe how weight is caused by gravity and howgravity is different on the Earth and on the Moon

• explain contact friction in simple terms.

Suggested lesson allocation (see individual lesson planning guides)Direct route

K1Forces andgravity

K2Friction

K3Balancedforces

K4Unbalancedforces

K5Slowdown!

K6Archimedes’ story: Think abouthow scientists test their ideas

Extra lessons (not in pupil book)

K2 FrictionExtra lesson for Activity K2a

Review and assess progress(distributed appropriately)

To make good progress, pupils starting this unitneed to: • know that pushes and pulls change the

speed, direction or shape of an object• know how to measure distance and how to

use a forcemeter to measure force in newtons• know that forces act in a particular direction

and this can be indicated by arrows• have experience of the effects of a variety of

forces, e.g. magnetic, gravity, friction, airresistance.

➞ Transition quiz for unit K

MisconceptionsPupils may associate the word force with coercion and with general non-scientific use, e.g. police force. Many pupils tend to associate forces only withmovement. Pupils may also believe a force is something contained within a moving object, which when the moving object has stopped has been ‘usedup’. Pupils tend to see a force as being a property of a single object and weight is often seen as a property of an object and gravity a property ofspace. Pupils may believe that the forces have ceased to act when equilibrium exists and that friction is acting all the time. Pupils may believe thatwhen something is moving at a steady speed there is a steady force acting on it.

Health and safety (see activity notes to inform risk assessment)Pupils should wear eye protection when stretching springs or rubber bands. Pupils should take care not to drop heavy weights on their toes.

K1Lesson planning

guideForces and gravity


Learning outcomes

Most pupils will … Some pupils, making less progress will … Some pupils, making more progress will …

• describe the relationship between massand weight

• record measurements of mass andweight in the appropriate units.

• distinguish between mass and weight • record measurements of mass and weight in

the appropriate units.

• explain how weight is caused by gravity actingon a mass and apply this to the effects of gravityon the Moon.

Learning objectivesi Gravitational attraction pulls an object and the Earth towards each other.ii Weight is a force caused by gravity acting on a mass and is measured in newtons.iii Mass is the amount of matter in an object and is measured in kilograms.

Scientific enquiryiv Use a forcemeter to measure forces. (Framework YTO Sc1 7d)v Present and interpret experimental results through the routine use of tables, bar charts and simple graphs, including line graphs. (Framework YTO

Sc1 7f)vi Relate conclusions to scientific knowledge and understanding. (Framework YTO Sc1 7g)

Suggested alternative starter activities (5–10 minutes)

Introduce the unit Share learning objectives Word game Capture interest (1) Capture interest (2)

Unit map for Forcesand their effects.

• Find out the differencebetween mass and weight.

• Be able to present andinterpret results. (Sc1)

Pupils sort cardsto match pictureswith names offorces.

Show an animation of someonein a lift standing on weighingscales. Catalyst InteractivePresentations 1

Show video clips of astronautson the Moon and in a spaceshuttle.Catalyst InteractivePresentations 1

Suggested alternative main activitiesActivity Learning

objectivessee above

Description Approx.timing

Target group

C H E S

Textbook K1 i, ii and iii Teacher-led explanation and questioning OR pupils work individually,in pairs or in small groups through the in-text questions and thenonto the end-of-spread questions if time allows.

35 min R/G G R S

Activity K1aPractical

ii, iii, iv, vand vi

Mass and weight Pupils weigh objects (and themselves), draw agraph of mass against weight and use this to predict the weights ofother objects given their masses.

25 min ✓ ✓ ✓

Activity K1bPaper

i, ii and iii Gravity on Earth and Moon To reinforce that weight is caused bygravity and the difference between mass and weight. Pupils carry outcalculations to convert between the mass and weight on Earth and onthe Moon.

20 min ✓

Suggested alternative plenary activities (5–10 minutes)Review learning Sharing responses Group feedback Word game Looking aheadPupils give examples of howfive fources are useful ineveryday life.

Pupils share responsesfrom Activity K1a.

Pupils share feedback onActivity K1b (Extension).

Pupils identify theodd one out inlists of words.

Pupils suggest consequencesof changes to the Earth’sgravity.

Key wordsgravitational attraction, gravity, newton, weight, matter, mass, kilograms

Out-of-lesson learningHomework K1Textbook K1 end-of-spread questionsActivity K1b

K2Lesson planning

guideFriction


Learning outcomes

Most pupils will … Some pupils, making less progress will … Some pupils, making more progress will …• describe differences in behaviour in

terms of different frictional forces• identify the characteristics of

lubricants and examples of wherefriction is useful.

• explain how friction slows things down andlubricants reduce friction

• give one example of where friction can beuseful.

• apply their knowledge of friction to themovement of vehicles and car safety.

Learning objectivesi Friction is a force that opposes motion.ii Friction between two surfaces can be reduced, e.g. with a lubricant.iii Frictional forces can be useful.

Scientific enquiryiv Identify and control the key factors that are relevant to a particular situation. (Framework YTO Sc1 7c)v Present and interpret experimental results using tables and line graphs. (Framework YTO Sc1 7f)


Recap last lesson Share learning objectives Brainstorming Problem solving Capture interest

Remind pupils of thedifference betweenmass and weight.

• Find out what friction is.• Find out how friction can be useful or

reduced.• Be able to present and interpret line

graphs. (Sc1)

Ideas aboutfriction.

Show a presentation oflow- and high-frictionsituations. Catalyst InteractivePresentations 1

Show an object needinglubrication and ask for ideasto get it working better.


objectivessee above


Target group

C H E S

Textbook K2 i, ii and iii Teacher-led explanation and questioning OR pupils work individually,in pairs or in small groups through the in-text questions and thenonto the end-of-spread questions if time allows.

20 min R/G G R S


i, iv, and v Shoe soles Pupils investigate the relationship between the mass of ashoe and the forces needed to pull it along.

35 min ✓ ✓

Activity K2b Paper

i, ii and iii A world without friction Pupils write about their imaginedexperiences if there was no friction.

20 min ✓

Suggested alternative plenary activities (5–10 minutes)Review learning Sharing responses Group feedback Word game Looking aheadPupils list reasons toprove or disprove astatement.

Pupils share theirwritten work fromActivity K2b.

Pupils prepare a sentence tosummarise their findings inActivity K2a.

Pupils generate fivequestions and answerson small pieces of card.

Pupils suggest ways to modelhow a lubricant reduces the forceof friction.

Key wordsfriction, lubricants

Out-of-lesson learningHomework K2Textbook K2 end-of-spread questions Activity K2bCollect advertisements and publicity relating to reducing friction, e.g. in cars, bicycles, sports clothing,oils and lubricants

K3Lesson planning

guideBalanced forces


Learning outcomes

Most pupils will … Some pupils, making less progress will … Some pupils, making more progress will …• use arrows to scale to show situations

in which the forces are balanced in arange of situations including floating.

• use arrows to scale to show situations in whichthe forces are balanced, e.g. upthrust andweight.

• apply their knowledge of balanced forces in awider range of contexts such as a car moving atsteady speed

• interpret their results on floating, usingknowledge of balanced forces to explainconclusions.

Learning objectivesi Force arrows show the direction and size of a force. ii Situations in which forces are balanced. iii Why objects float and what upthrust is.iv When an object is moving at a constant speed the forces are balanced. (red only)

Scientific enquiryv Present and interpret experimental results using tables and line graphs. (Framework YTO Sc1 7f)


Recap last lesson Share learning objectives Problem solving Capture interest (1) Capture interest (2)

How friction stopsthings moving.

• Find out about balanced forces.• Be able to use force arrows.• Be able to present and interpret graphs.

(Sc1)

Decide if forces are apush, a pull or atwist.

Use a car or other vehicleto talk about size anddirections of forces.

Show an animation ofbalanced forces. Catalyst InteractivePresentations 1


objectivessee above


Target group

C H E S

Textbook K3 i, ii, iii andiv

Teacher-led explanation and questioning OR pupils work individually, inpairs or in small groups through the in-text questions and then ontothe end-of-spread questions if time allows.

35 min R/G G R S


ii, v Stretching Pupils investigate the effect of a stretching force on aspring and consider the relationship between weight and extension.Extension sheet: Pupils compare the results from stretching a rubberband with the results from the spring experiment.

25 min ✓ ✓

Activity K3bPractical

iii Floating and upthrust Pupils investigate floating and sinking indifferent liquids.

25 min ✓ ✓ ✓

Activity K3cPaper

i, ii, iii andiv

Balanced forces Pupils look at pictures of a range of situations whereobjects are stationary and the forces are balanced. They decide whatforces (and their direction) are acting on them and explain why theobjects don’t move.

10 min ✓

Suggested alternative plenary activities (5–10 minutes)Review learning Sharing responses Group feedback Brainstorming Looking aheadPupils label diagramsinvolving balancedforces.

Pupils share their resultsand responses fromActivity K3a.

Pupils discuss theirresults from ActivityK3b.

Pupils think about situationsin everyday life in which thereare balanced forces.

Pupils apply their ideas offorces to describe how buoysfloat on the sea.

Key wordsforce arrows, balanced, reaction force, floats, upthrust, extension, red only: sinks

Out-of-lesson learningHomework K3Textbook K3 end-of-spread questionsActivity K3c

K4Lesson planning

guideUnbalanced forces


Learning outcomes


• use arrows to scale to show situations inwhich the forces are unbalanced in arange of situations including getting ago cart to move and a car to movefaster.

• begin to use force arrows to scale and describesituations in which the forces are unbalanced.

• apply their understanding of unbalanced forcesto a range of situations and be able to calculatethe size of the resultant force.

Learning objectivesi In some situations forces are unbalanced. ii Unbalanced forces change the direction or speed of a moving object.

Scientific enquiryiii Describe and explain what results show when drawing conclusions. (Framework YTO Sc1 7g)


Recap last lesson Share learning objectives Problem solving (1) Problem solving (2) Capture interest

There can be severalbalanced forces onan object.

• Find out about unbalancedforces.

• Be able to explain resultsand draw conclusions. (Sc1)

Pupils draw force arrowson diagrams to balancethe forces.

Pupils discuss the effect ofunbalanced forces on thediagrams provided.

Show photos of a rugby scrumand discuss the forces.Catalyst InteractivePresentations 1


objectivesee above


Target group

C H E S

Textbook K4 i and ii Teacher-led explanation and questioning OR pupils work individually, inpairs or in small groups through the in-text questions and then ontothe end-of-spread questions if time allows.

35 min R/G G R S


i, ii and iii All unbalanced! Demonstration of four different unbalanced scenarios,one of which is Extension only.

20 min ✓ ✓ ✓

Activity K4bPaper

i and ii Unbalanced forces Pupils answer questions on the effects ofunbalanced forces on an object.

20 min ✓ ✓

Suggested alternative plenary activities (5–10 minutes)Review learning Sharing responses Group feedback Word game Looking aheadPupils draw diagrams toshow situations in whichthe forces are unbalanced.

Pupils compare theirpredictions with whathappened in Activity K4a.

Pupils write down whatthey have learnt from thelesson and share this witha partner, and then withanother pair.

Check progress using atrue/false quiz on work sofar in the unit.

Pupils discuss a definitionfor the speed of a movingobject.

Key wordsunbalanced forces, air resistance, red only: resultant force

Out-of-lesson learningHomework K4Textbook K4 end-of-spread questionsActivity K4b

K5Lesson planning

guideSlow down!


Learning outcomes


• describe what is meant by speed• compare speeds qualitatively identifying

that the stopping distance for a carrelates to its speed and frictional forces.

• compare speeds qualitatively and recognisethat friction opposes motion.

• apply their understanding of speed and be ableto calculate speeds.

Learning objectivesi Speed and the units in which it is measured.ii Stopping distances of vehicles related to speed and frictional forces. iii Calculate speed. (red only)

Scientific enquiryiv Interpret results through routine use of tables, bar charts and line graphs. (Framework YTO Sc1 7f)


Recap last lesson Share learning objectives Problem solving Capture interest (1) Capture interest (2)

Show unbalancedforces, using a toycar.

• Find out what speed is andhow it is measured.

• Find out what stoppingdistance is.

• Be able to interpret adistance-time graph. (Sc1)

Pupils match somespeeds to differentsituations.

Quiz about speed. Show photos of speedscenarios.Catalyst InteractivePresentations 1


objectivessee above


Target group

C H E S

Textbook K5 i, ii and iii Teacher-led explanation and questioning OR pupils work individually, inpairs or in small groups through the in-text questions and then ontothe end-of-spread questions if time allows.

35 min R/G G R S

Activity K5aPaper

i, ii and iv School journey Pupils describe a journey from a distance-time graph. 25 min ✓ ✓

Activity K5bCatalyst InteractivePresentations 1

i and ii Pupils investigate how frictional forces slow things down. 25 min ✓

Suggested alternative plenary activities (5–10 minutes)Review learning Sharing responses Group feedback Word game Looking backPupils match sets ofdistance-time data tosuitable situations.

Pupils share descriptions oftheir distance-time graphsfrom Activity K5a.

Pupils make a poster to explainto driving school students whatstopping distance is.

Pupils write a short poemabout speed using keywords.

Pupils revise andconsolidate knowledgefrom the unit.

Key wordsspeed, metres per second, m/s, kilometres per hour, km/h, thinkingdistance, braking distance, stopping distance

Out-of-lesson learningHomework K5Textbook K5 end-of-spread questions

K6Lesson planning

guideArchimedes’ story – Think abouthow scientists test their ideas


Learning outcomes


• describe how Archimedes checked thepurity of a gold crown by measuring itsvolume by displacement, stating that itmust have had some lighter metal in itbecause its volume was larger althoughits mass was the same.

• describe how Archimedes checked the purity ofa gold crown by measuring its volume bydisplacement.

• also calculate density.

Learning objectivesi To understand how Archimedes checked the purity of a gold crown by measuring its volume by displacement.ii To know that density is mass divided by volume. (red only)The structure of this lesson is based around the CASE approach. The starter activities give concrete preparation. The lesson then moves away from theconcrete towards a challenging situation, where pupils need to think. The plenary activities give pupils time to discuss what they have learnt, to committheir understanding to paper and express their ideas verbally to the rest of the class.

Scientific enquiryiii Consider early scientific ideas, including how experimental evidence and creative thinking have been combined to provide scientific explanations.

(Framework YTO Sc1 7a)


Bridging to the unit Setting the context Concrete preparation (1) Concrete preparation (2)

Demonstrate that upthrustis a force.

Introduce the story of Archimedesand the crown.

Demonstrate lowering an object into acontainer brimful of water andcollecting the displaced water.

Pass round cubes of the same volumeof different materials, so pupils canexperience the difference in weight.

Main activityActivity Learning

objectivesee above


Target group

C H E S

Textbook K6 i, ii and iii Teacher-led explanation and questioning OR pupils work individually, inpairs or in small groups through the in-text questions and then ontothe end-of-spread questions if time allows.

35 min R/G G R S

Suggested alternative plenary activities (5–10 minutes)Group feedback Bridging to other topicsPupils discuss how they might have tackled the King’s problem. Pupils will have other opportunities to see how scientists work in other

units.

Key wordsdisplaces, dense, red only: density

Out-of-lesson learningTextbook K6 end-of-spread questions

K1

© Harcourt Education Ltd 2003 Catalyst 1This worksheet may have been altered from the original on the CD-ROM.

StartersForces and gravity

Sheet 1 of 1

Introduce the unit● Either draw the outline of the unit map on the board

then ask pupils to give you words to add, saying whereto add them. Suggest some yourself when necessary tokeep pupils on the right track.

● Or give out the unit map and ask pupils to work ingroups deciding how to add the listed words to thediagram. Then go through it on the board as eachgroup gives suggestions.

Share learning objectives● Ask pupils to write a list of FAQs they would put on a

website telling people about weight, mass and gravity.Collect suggestions as a whole-class activity, steeringpupils towards those related to the objectives. Concludeby highlighting the questions you want them to be ableto answer at the end of the lesson.

Word game ● Make a set of cards for each group from the pupil sheets.

● Pupils lay down the word cards (forces), then sort thepicture cards to match these forces.

● Each group can feedback their choices for one of theforces to the class. This may produce interestingdiscussion. (For example, pupils may match theparachutist card with gravity or air resistance. Bothforces are acting, so both answers are correct.)

Capture interest (1)● Show the animation of someone in a lift standing on

some weighing scales. The reading changes as the liftstarts and stops.

● Discuss what is happening in terms of mass and weight.

Capture interest (2) ● Use the video sequence of astronauts in the space shuttle

to show that the ‘floating around’ is not due to lack ofair. Then use the sequence of astronauts walking on theMoon to show that there is a difference between massand weight. Some notes on weight, orbits and free fallare provided on the teacher sheet.


Unit map for Forces andtheir effects.

● Find out the differencebetween mass andweight.

● Be able to present andinterpret results. (Sc1)

Pupils sort cards to matchpictures with names offorces.

Show an animation ofsomeone in a lift standingon weighing scales. Catalyst InteractivePresentations 1

Show video clips ofastronauts on the Moon andin a space shuttle.Catalyst InteractivePresentations 1

Introduce the unit Share learning Word game Capture interest (1) Capture interest (2)objectives

➔ Pupil sheets

➔ Unit map

➔ Catalyst Interactive Presentations 1

➔ Catalyst Interactive Presentations 1➔ Teacher sheet

© Harcourt Education Ltd 2003 Catalyst 1This worksheet may have been altered from the original on the CD-ROM. Sheet 1 of 1

K Unit mapForces and their effects

air resistancebrakingdensedensity Rextensionfloatingforce arrowsforcemetergravitational attraction Rkilogramskilometres per hourlubricant

magnetismmassmattermetres per secondnewtonsreaction forceresultant force Rsinkingslowing downvolume Rweight

Copy the unit map and use these words to help you complete it. You may add words of your own too.

�

Forces andtheir effects

Gravity Balancedforces

Unbalanced forces

Upthrust

Friction

Speed


Word game

K1 StartersForces and gravity

friction

gravity

airresistance

magnetism

�

�

chalk



Word game

�

�


Capture interest (2)

Teacher sheet: Notes on weight, orbits and free fallPoints to discuss with pupils:

● Our weight is the force attracting us to the centre of the Earth, or,if we are on the Moon, to the centre of the Moon. Because theMoon has a smaller mass than the Earth, the force is less there. Weweigh less on the Moon but our size and shape is unchanged; wehave not lost mass.

● However, our weight is not zero on the Moon; if astronauts jumpon the Moon they still come back down. (If pupils think this isbecause of heavy boots, reason that if there was no gravity theboots would not weigh anything either.)

● Point out that when we refer to ‘losing weight’ by dieting, wereally mean losing mass.

● Contrary to what some pupils believe, it makes no differencewhether there is any air or not. Astronauts in the space shuttle‘float around’ but are still breathing air. They do not need to wearspace suits.

Points to be aware of:

● Weight is the force that keeps the space shuttle and astronauts inorbit. If they were weightless or in zero gravity, they would driftoff into space. In orbit they are neither weightless nor in zerogravity. However, these terms are in common use and cause muchconfusion to pupils in the future.

● Teachers can help by avoiding the term ‘weightless’ whendescribing astronauts in the space shuttle. The correct term is freefall. When repeating pupils’ comments modify them using phraseslike ‘the astronauts appear to be weightless’ or ‘seem to be in zerogravity’.


K2


StartersFriction

Sheet 1 of 1

Recap last lesson● Use a tin of baked beans to help you explain that mass

is the amount of matter in kilograms and weight is aforce in newtons.

● Ask what happens to mass and weight in thesesituations:1 On a shelf2 If beans are eaten3 In a rocket in deep space4 On the Moon5 In a lift

6 On a rollercoaster7 On space shuttle in orbit


website telling people about friction. Collectsuggestions as a whole-class activity, steering pupilstowards those related to the objectives. Conclude byhighlighting the questions you want them to be able toanswer at the end of the lesson.

Brainstorming● Ask each group of pupils to brainstorm situations where

friction arises and write them on a large piece of paperto feedback to the class.

Problem solving● Pupils look at a presentation of a water slide, ice

skating, a gymnast on bars, a car braking, frying an egg,walking across a polished floor and car wheels spinningon ice.

● They tick on their pupil sheet whether high or lowfriction is needed for each one.

Capture interest● Show an object that needs lubricating. This could be a

toy, a bicycle, or anything with metal moving parts.Even unscrewing a rusty bolt is easier with WD40.

● Demonstrate how poorly it works at first, then oil itand show it working properly.


Remind pupils of thedifference between massand weight.

● Find out what friction is.● Find out how friction

can be useful orreduced.

● Be able to present andinterpret line graphs.(Sc1)

Ideas about friction. Show a presentation oflow- and high-frictionsituations. Catalyst InteractivePresentations 1

Show an object needinglubrication and ask forideas to get it workingbetter.

Recap last lesson Share learning Brainstorming Problem solving Capture interest objectives

Equipmenttin of baked beans

AnswersMass Weightsame sameless lesssame zerosame lesssame appears to change on starting

and stoppingsame appears to change same appears to be zero

➔ Catalyst Interactive Presentations 1➔ Pupil sheet

Equipmentmetal object, oil lubricant


Problem solvingLook at the video clips. Do you need high or low friction in these situations? Sometimes your life may depend on it! Use ticks ✓ to complete the table.

K2 StartersFriction

Situation High friction needed Low friction needed

water slide

ice skating

gymnast on bars

car braking

frying an egg

rock climbing

car wheels slipping on ice


K2 Starters

�

Friction

Problem solvingLook at the video clips. Do you need high or low friction in these situations? Sometimes your life may depend on it! Use ticks ✓ to complete the table.

Situation High friction needed Low friction needed

water slide

ice skating

gymnast on bars

car braking

frying an egg

rock climbing

car wheels slipping on ice

K3


StartersBalanced forces

Sheet 1 of 1

Recap last lesson● Pass around some high- and low-friction materials, and

ask what characteristics are common to high-frictionsurfaces and to low-friction surfaces.


website telling people about balanced foces. Collectsuggestions as a whole-class activity, steering pupilstowards those related to the objectives. Conclude byhighlighting the questions you want them to be able toanswer at the end of the lesson.

Problem solving● Demonstrate a push, a pull and a twist (e.g. open and

shut a door, turn a key).

● Ask pupils to complete the pupil sheet, then gothrough it as a whole-class discussion.

Capture interest (1)● Use a toy car. Give it a push, or ask a pupil to do this.

Talk about the force needed to get it moving (could usea push or a pull) and why it stops.

● Some pupils will think it stops because you stoppushing it, but you could ask if it would go further on asmooth surface, or if it was oiled. Aim to get them totell you that it would go further if the friction wasreduced.

● Extension: Discuss whether, if you could reduce thefriction to nothing, this would mean the car wouldcarry on and not stop.

Capture interest (2)● Show the animation about balanced forces.

● Ask pupils to explain how the forces are balanced.


How friction stops thingsmoving.

● Find out about balancedforces.

● Be able to use forcearrows.

● Be able to present andinterpret graphs. (Sc1)

Decide if forces are a push,a pull or a twist.

Use a car or other vehicleto talk about size anddirections of forces.

Show an animation ofbalanced forces. Catalyst Interactive Presentations 1

Recap last lesson Share learning Problem solving Capture interest (1) Capture interest (2)objectives

➔ Pupil sheet

Equipmentsuggested materials: sandpaper, glass, PTFEtape, Teflon-coated pan, floor vinyls (somecan be smooth but non-slip)

Equipmenttoy car



Problem solvingAre the forces involved in each action a pushing force, a pulling force, or a twisting/turning force? Use ticks � to complete the table.

K3 StartersBalanced forces

K3 Starters

�

Balanced forces

Action Pushing Pulling Twisting/turningan electromagnet lifting scrap metala digger lifting earth in a scoopa shopping bag hanging on your armundoing the lid of a jam jarkicking a ballthrowing a stonea car towing a caravana food processor chopping an onionpedalling a bikeriding in a horse-drawn carriagepaddling a canoetowing a water skier


Problem solvingAre the forces involved in each action a pushing force, a pulling force, or a twisting/turning force? Use ticks � to complete the table.

Action Pushing Pulling Twisting/turningan electromagnet lifting scrap metala digger lifting earth in a scoopa shopping bag hanging on your armundoing the lid of a jam jarkicking a ballthrowing a stonea car towing a caravana food processor chopping an onionpedalling a bikeriding in a horse-drawn carriagepaddling a canoetowing a water skier

K4


StartersUnbalanced forces

Sheet 1 of 1

Recap last lesson● Use a toy car to demonstrate balanced and unbalanced

forces: on a slope, a flat surface or a banked curve.

● You could suspend it on a string and balance it on asurface to show that if the forces balance it won’tchange its movement.

● Attach three strings to the car with pupils pulling inthree directions.

● Show that, if the forces are not balanced, it will start tomove, speed up, slow down, stop moving or changedirection.


website telling people about unbalanced forces. Collectsuggestions as a whole-class activity, steering pupilstowards those related to the objectives. Conclude byhighlighting the questions you want them to be able toanswer at the end of the lesson.

Problem solving (1)● Hand out the pupil sheet. Ask pupils to draw in the

other force arrow to balance the object in eachdiagram.

Problem solving (2)● Hand out the pupil sheet. Ask pupils to discuss in

groups how unbalanced forces are affecting the objectsshown.

● Compare the groups’ responses in a class discussion.

Capture interest● Show the photos of a rugby scrum and discuss how the

friction force balances the pushing force. Ask whatwould happen if the pushing force was not balanced.


There can be severalbalanced forces on anobject.

● Find out aboutunbalanced forces.

● Be able to explainresults and drawconclusions. (Sc1)

Pupils draw force arrowson diagrams to balancethe forces.

Pupils discuss the effect ofunbalanced forces on thediagrams provided.

Show photos of a rugbyscrum and discuss theforces.Catalyst InteractivePresentations 1

Recap last lesson Share learning Problem solving (1) Problem solving (2) Capture interestobjectives

Equipmenttoy car, string

➔ Pupil sheet

➔ Pupil sheet



Problem solving (1)Draw a force arrow to balance the forces shown in each diagram.Think about the direction and size of your arrows.

K4 StartersUnbalanced forces

1

team A

Team A are pulling with a force marked F.

The tractor is moving at asteady speed.

The crate does not move.This force is theweight of the lamp.

team B

F

F

F

F

2

4

3

5

F G

Draw a third tractor pulling with force Hto exactly balance, so no tractor moves.


K4 StartersUnbalanced forces

Problem solving (2)Look at the pictures and describe how unbalanced forces areaffecting the objects.

A B

can beingcrushed

football beingkicked

C

tennis ball beinghit with racket

K5


StartersSlow down!

Sheet 1 of 1

Recap last lesson● Demonstrate with a toy car that balancing the forces on

an object requires the right size force, but also the forcemust be in the right direction. If forces are notbalanced, the car starts, stops, speeds up, slows down orchanges direction.


website telling people about speed. Collect suggestionsas a whole-class activity, steering pupils towards thoserelated to the objectives. Conclude by highlighting thequestions you want them to be able to answer at theend of the lesson.

Problem solving● Pupils match the correct speed with each situation on

the pupil sheet.

● Go through the answers with the class.

Capture interest (1)● Pupils do the quiz on the pupil sheet.

● Go through the answers with the class.

Capture interest (2)● Show the photos of various speed scenarios. Ask what

happens to the objects if the forces on them areunbalanced.

● Explain that objects start, stop, speed up, slow down orchange direction depending on the forces acting onthem.


Show unbalanced forces,using a toy car.

● Find out what speed isand how it is measured.

● Find out what stoppingdistance is.

● Be able to interpret adistance-time graph.(Sc1)

Pupils match some speedsto different situations.

Quiz about speed. Show photos of speedscenarios.Catalyst InteractivePresentations 1

Recap last lesson Share learning Problem solving Capture interest (1) Capture interest (2)objectives

➔ Pupil sheetAnswersfingernails growing � 0.1 mm/dayConcorde � 625 m/sspeed of light � 30 000 000 m/sathlete running 100 m � 10 m/sathlete swimming 100 m � 2 m/scar at 60 mph � 27 m/swalking slowly � 1 m/s

➔ Pupil sheetAnswers1a; 2b; 3c; 4c; 5b; 6b

Equipmenttoy car



Problem solving

Match the moving object to the correct speed.

Fingernails growing ● ● 2 m/s

Concorde ● ● 30 000 000 m/s

Speed of light ● ● 0.1 mm/day

World-class athlete running 100 m ● ● 10 m/s

World-class athlete swimming 100 m ● ● 1 m/s

Car at 60 mph ● ● 625 m/s

Walking slowly ● ● 27 m/s

K5 StartersSlow down!

K5 Starters

�


Slow down!

Problem solving

Match the moving object to the correct speed.

Fingernails growing ● ● 2 m/s

Concorde ● ● 30 000 000 m/s

Speed of light ● ● 0.1 mm/day

World-class athlete running 100 m ● ● 10 m/s

World-class athlete swimming 100 m ● ● 1 m/s

Car at 60 mph ● ● 625 m/s

Walking slowly ● ● 27 m/s


Capture interest (1)

Speed quiz1 What is the fastest mammal?

a cheetahb horsec wolf

2 Thrust SSC holds the land speed record for the fastest mile. (It wasalso the first car to exceed the speed of sound.) What is this record?a 390 mphb 763 mphc 1005 mph

3 How fast can a very fast snail move?a 50 cm/hb 5 m/hc 50 m/h

4 What is the fastest speed by an aeroplane?a 21.93 mphb 219.3 mphc 2193 mph

5 Which is the fastest bird?a the red throated humming birdb the spine tailed swiftc the peregrine falcon

6 What was the skateboard speed record set in 1998 by GaryHardwick?a 16.3 mphb 63 mphc 163 mph

K5 StartersSlow down!

K6


StartersArchimedes’ story – Thinkabout

Sheet 1 of 1

Bridging to the unit● Suspend a weight (1 kg) on a forcemeter (10 N).

● Now show what happens as you lower it into water(collect the displaced water). The reading on theforcemeter goes down. This must be because of anupward force on the weight (called upthrust), whichpartly counteracts the downward force (weight). If theupward force were big enough, the object would float.

● The reading on the forcemeter should be about 8 or 9 N– this means that the upthrust on the weight isbetween 1 and 2 N. If you weighed the displaced waterits weight would be equal to the upthrust.

● To bridge to the experiment, measure upthrusts forother items, including a large wooden block whichfloats (so upthrust = weight).

Setting the context● Introduce the story of Archimedes and the crown, and

the period of history in which it took place.

● Ask which is heavier, a tonne of feathers or a tonne ofcoal? (They are the same!)

● Ask which is lighter, milk or cream? (Cream – it floatson milk.)

Concrete preparation (1)● Demonstrate lowering an object into a container

brimful of water and collecting the displaced water. Usea large washing up bowl or trough and collect the waterin a tray.

Concrete preparation (2)● Pass round cubes of the same volume of different

materials, so that pupils can experience the differencein weight.

Bridging to the unit Setting the context Concrete preparation (1) Concrete preparation (2)


Demonstrate that upthrust is aforce.

Introduce the story ofArchimedes and the crown.

Demonstrate lowering an objectinto a container brimful of waterand collecting the displacedwater.

Pass round cubes of the samevolume of different materials, sopupils can experience thedifference in weight.

➔ Technician sheet

➔ Technician sheet

Equipmentcubes for density investigation (e.g. from Philip Harris)


Bridging to the unit

Technician sheetSupply the following for a demonstration:

● forcemeter

● 1 kg weight, with a method of suspending it from the forcemeter

● container of water in which the weight can be immersed, whilehanging from forcemeter

● tray or bowl to collect the displaced water from the container

● measuring cylinder large enough to take the displaced water.

K6 StartersArchimedes’ story

Concrete preparation (1)

Technician sheetSupply the following for a demonstration:

● large washing up bowl or trough brimful of water, placed on atray

● large object which will sink when placed in the water

● suitable funnel arrangement for collecting all the water from thetray without spills

● measuring cylinder which will take a volume of water equal tovolume of the metal object.

K6 StartersArchimedes’ story

�


Sheet 1 of 1© Harcourt Education Ltd 2003 Catalyst 1This worksheet may have been altered from the original on the CD-ROM.

Running the activityPupils will need calculators.

Core: Pupils work through the sheet in order. Some pupils may not need to checkthe mass of the hanger on the electronic balance. Many pupils will need help touse the graph to find the weight of A and the mass of B; it may help to have agraph on white board or OHT, and demonstrate drawing a line from a massquantity to the graph line, and then to the weight axis.

Help: Pupils will need the Core sheet for the instructions. The Help sheets thengive them a table and graph axes to use to present results, and questions toanswer.

Extension: There is less guidance on the sheet and pupils can investigate their ownmass and weight.

At the end of the activity, highlight the fact that 1 kg has a weight of 10 N.

Other relevant materialSkill sheet 5: Drawing charts and graphs

Skill sheet 18: Reading from graphs

Expected outcomesPupils should discover a straight-line relationship, and that weight isapproximately 10 times mass (on Earth). 1 kg has a weight of 10 N.

PitfallsElectronic balances are often too precise, and forcemeters (Newton springbalances) are the reverse. Working to the nearest gram should obviate this. Bealert for pupils who do not want to weigh themselves, and give them alternatives– to weigh the teacher, or a box of textbooks, or to use a friend’s results.

Safety notesIf pupils use a substitute like a box of books, teach them how to lift it safely. Iflarge masses are used place a ‘catch box’ containing polystyrene packaginggranules or similar below the hanging weights.

AnswersCore:

The masses and weights of A and B will depend on the examples that youhave found, but should agree with 100 g has a weight of 1 N.

/ Pupils should find that weight is approximately 10 times mass.

Help:

As Core

a 10 b 10

Extension:

/ / As Core

Pupils’ masses will typically range between 35 kg and 60 kg.

K1aTeacher

activity notesMass and weight

Practical Pupils learn the connection between mass and weight. They weigh objects to find their Core, Help, Extensionmass in kilograms, and Extension pupils find their weight in newtons.

Type Purpose Differentiation

3

3

1

1

1

2

2

2

4



Skill sheet 18: Reading from graphs

Equipment neededFor each group:

● a forcemeter (Newton spring balance) reading up to 5 newtons● four slotted masses and hanger (either 50 g or 100 g would be suitable).

For the class:

● electronic top-pan balance(s) recording up to 500 g● a stone/large rubber bung/small sand or bean bag – mass approximately half that

of the masses and hanger (i.e. 125 g or 250 g) – clearly labelled ‘A’. If possible,have more than one of these with the identical mass

● a similar object, of slightly different mass, clearly labelled ‘B’ – again more thanone if possible. It should be possible to hang B from the forcemeter

● bathroom scales, calibrated in kg● bathroom scales, calibrated in newtons.

For your informationRunning the activityPupils will need calculators.

Core: Pupils work through the sheet in order. Some pupils may not need to checkthe mass of the hanger on the electronic balance. Many pupils will need help to usethe graph to find the weight of A and the mass of B; it may help to have a graph onwhite board or OHT, and demonstrate drawing a line from a mass quantity to thegraph line, and then to the weight axis.

Help: Pupils will need the Core sheet for the instructions. The Help sheets then givethem a table and graph axes to use to present results, and questions to answer.

Extension: There is less guidance on the sheet and pupils can investigate their ownmass and weight.At the end of the activity, highlight the fact that 1 kg has a weight of 10 N.

Expected outcomesPupils should discover a straight-line relationship, and that weight is approximately10 times mass (on Earth). 1 kg has a weight of 10 N.

PitfallsElectronic balances are often too precise, and forcemeters (Newton spring balances)are the reverse. Working to the nearest gram should obviate this. Be alert for pupilswho do not want to weigh themselves, and give them alternatives – to weigh theteacher, or a box of textbooks, or to use a friend’s results.

Safety notesIf pupils use a substitute like a box of books, teach them how to lift it safely. If largemasses are used place a ‘catch box’ containing polystyrene packaging granules orsimilar below the hanging weights.

K1aTechnician

activity notesMass and weight

Practical Pupils learn the connection between mass and weight. They weigh objects to find their Core, Help, Extensionmass in kilograms, and Extension pupils find their weight in newtons.


Sheet 1 of 1

K1a


ActivityCore

You are going to find out how an object’s weight is related to its mass.

Obtaining evidence1 Put a hanger on the electronic balance. Measure its mass in grams.

Record it in a table like the one below (in step 8).2 Use the forcemeter to measure the weight of the hanger, in newtons.

Record the answer in your table.3 Now use the hanger and one slotted mass. Measure the total mass on

the electronic balance, then measure the weight on the forcemeter. Record the answers in your table.

4 Carry on adding slotted masses until you have five results.

5 Measure the mass of object A on the electronic balance. Write it down.

6 Measure the weight of object B on the forcemeter. Write it down.

7 Use the conversion chart to convert the mass in grams to kilograms ifyou need to. You will use this for your graph later.

Presenting the results8 Use a table like this to record your results.

9 Draw a line graph of your results. Put the mass in kilograms on the x-axis and the weight in newtons on the y-axis. Use a ruler to draw astraight line even if all the crosses do not fit exactly on it.

Considering the evidenceUse your graph to find out the weight of A, and the mass of B. Writedown your answers. If you have time, check them on the balances.Compare the mass and weight for objects A and B. Use your calculatorto divide the weight by the mass. Write down your conclusion.Check some other points on your graph by reading off the weight fromthe mass. Do these fit with your conclusion?

Mass and weight

5

4

3

2

1

0N

Mass in Mass ingrams kilograms

100 0.1

200 0.2

300 0.3

400 0.4

500 0.5

Mass in grams Mass in kilograms Weight in newtons

2

3

1

Keep fingers andtoes away fromany weights thatmay fall!

!

Sheet 1 of 2

K1a


ActivityHelp

You are going to find out how an object’s weight is related to its mass.

Presenting the results1 Use this table to record your results.

Mass of object A = ............. grams Weight of object B = ............. newtons

2 Use this grid to plot your results as a line graph. Use a ruler to draw astraight line, even if all the crosses do not fit on it exactly.

Mass and weight

Weightin N

Mass in kg0

0

1

2

3

4

5

0.1 0.2 0.3 0.4 0.5


Sheet 2 of 2

K1a


ActivityHelp

Considering the evidenceUse your graph to find out the weight of A, and the mass of B.

Weight of object A = ............. newtons Mass of object B = ............. gramsCheck the weight of A and the mass of B on the balances.Compare the mass and weight for objects A and B. Decide how much bigger the weight (in newtons) is than the mass (in kilograms).Complete the sentences below.

a Weight is ............. times the mass.

b When mass is 1 kg, weight is ............. N.

Mass and weight (continued)

2

1

Sheet 1 of 1

K1a


ActivityExtension

You are going to find out how an object’s weight is related to itsmass.

Obtaining evidence and presenting the results1 Put a hanger on the electronic balance. Measure its mass in

grams. Record it in a table like the one below.

2 Use the forcemeter to measure the weight of the hanger, innewtons. Write the answer in the table.

3 Now use the hanger and one slotted mass. Measure the totalmass on the electronic balance, then measure the weight on theforcemeter.

4 Carry on adding slotted masses until you have five results. Record your results in the table.

5 Measure the mass of object A on the electronic balance. Write itdown.

6 Measure the weight of object B on the forcemeter. Write it down.7 Use the bathroom scales to measure your mass in kilograms.

Write it down.8 In your table, convert each mass in grams to kilograms. You will

use this for your graph.9 Draw a line graph of weight in newtons against mass in

kilograms. Use a ruler to draw a straight line, even if the crossesdo not all fit on it exactly.

Considering the evidenceUse your graph to find out the weight of A, and the mass of B.Write down your answers. If you have time, check them on thebalances.Compare the mass and weight for objects A and B. Use yourcalculator to divide the weight by the mass. Can you see arelationship between them?Check some other points on your graph by reading off the weightfrom the mass. Do these fit with the relationship you can see?Predict your weight in newtons. If possible, use the newton scalesto see if you are correct.

Mass and weight


5

4

3

2

1

0N

2

3

4

1


Running the activityPupils work individually or in pairs to answer the questions on the sheet.

Answers1000 g or 1 kg

10 N

50 kg

10

1000 g or 1 kg

0.15 N

500 g or 0.5 kg, in the astronaut

300 kg

1 000 000 N on Earth, 150 000 N on the Moon

The probe will weigh less on the Moon. It requires less fuel to launch. It willbe less expensive to launch/it can go further with the same amount of fuel.

K1bTeacher

activity notesGravity on Earth and Moon

Paper Pupils reinforce learning of the relationship between mass and weight, and carry out Extensioncalculations to convert between the two.


3

8

9

12

4

56

7

10

Sheet 1 of 1

K1b


ActivityExtension

You are going to answer some questions about mass and weight.

Apples on EarthAn apple has a mass of about 100 g.On Earth it will weigh about 1 N.

What is the mass of 10 apples?How much do 10 apples weigh?What is the mass of a box of apples that weighs 500 N?

Apples on the MoonIf an astronaut took a box of 10 apples to the Moon, how many apples would he have when he got there (assuming he didn’t eat any)?

If the number of apples doesn’t change, then the mass will stay the same.

What will be the mass of the apples on the Moon?How much will the 10 apples weigh on the Moon?If the astronaut eats 5 of the apples, what is the mass of all the apples that are left? Where is the rest of the mass?What is the mass of a space buggy that weighs 450 N on the Moon?

Sending spacecraftA space shuttle has a mass of about 100 000 kg. How much doesit weigh on Earth? How much would it weigh if it landed on theMoon?

NASA would like to send a mission to Mars. The heavier something is, the more fuel it takes to launch it. Fuel is very expensive.

NASA would like to launch the Mars probe from the Moon. Why do you think they want to do this? Explain your answer.

Gravity on Earth and Moon

RememberOn Earth, 1 kg weighs 10 N.1 kg � 1000 g

RememberOn the Moon, the pullof gravity is about one-sixth that on Earth.To calculate the weightof an object on theMoon, you divide itsweight on Earth by 6.1 kg weighs about1.5 N on the Moon.

2

3

4

5

6

7

8

9

10

1


Running the activityCore: Pupils work in groups towards a full investigation. They write their plansbefore they start, then carry out the experiment and draw a graph of their results.They analyse their results and evaluate the experiment.

To make the experiment a fair test, the surface, shoe and masses should be thesame in each experiment.

Pupils should carry out each reading at least twice to obtain average results. Theexperiment will not take long to complete so this will not be too time-consuming.Pupils should record their results in a table that has columns for ‘Force needed innewtons’ and ‘Mass in grams’.

Help: The instructions are simpler, and there is a table for results and a graph gridwith axes for pupils to draw on. Pupils may need a calculator to help them workout averages.


ICT opportunitiesThe results can be graphed using a spreadsheet such as Microsoft® Excel.

Expected outcomesPupils carry out an investigation, and see that the heavier the shoe, the greaterthe friction.

PitfallsCare should be taken to make accurate readings when looking at forcemeters side-on. It is difficult to read the forcemeter at the same time as pulling it along – onepupil should pull while the other takes the reading.

AnswersCore:

As the mass in the shoe increases, so does the force needed to pull the shoe.

A greater mass causes more friction between the sole of the shoe and thesurface.

Suggestions: repeat the experiment more times, use a more accurateforcemeter or a pressure sensor

Help: As Core and

K2aTeacher

activity notesShoe soles

Practical Pupils investigate the relationship between the mass of a shoe and the force needed Core, Helpto pull it against friction.


1 2

3

1

2



EquipmentFor each pair/group:● a set of masses, 100–600 g● a shoe● a forcemeter● string● suitable surface to pull the shoe over, e.g. cork tile.

For your informationRunning the activityCore: Pupils work in groups towards a full investigation. They write their plansbefore they start, then carry out the experiment and draw a graph of their results.They analyse their results and evaluate the experiment.

To make the experiment a fair test, the surface, shoe and masses should be thesame in each experiment.

Pupils should carry out each reading at least twice to obtain average results. Theexperiment will not take long to complete so this will not be too time-consuming.Pupils should record their results in a table that has columns for ‘Force needed innewtons’ and ‘Mass in grams’.

Help: The instructions are simpler, and there is a table for results and a graph gridwith axes for pupils to draw on. Pupils may need a calculator to help them workout averages.

Expected outcomesPupils carry out an investigation, and see that the heavier the shoe, the greaterthe friction.

PitfallsCare should be taken to make accurate readings when looking at forcemeters side-on. It is difficult to read the forcemeter at the same time as pulling it along – onepupil should pull while the other takes the reading.

K2aTechnician

activity notesShoe soles

Practical Pupils investigate the relationship between the mass of a shoe and the force needed Core, Helpto pull it against friction.


Sheet 1 of 1

K2a


ActivityCore

You going to investigate the relationship between the mass of ashoe and the force needed to pull it against friction.

Equipment ● a set of masses● a shoe● a forcemeter● string● a suitable surface to pull the shoe over

Planning1 Decide how you are going to make the experiment fair.2 Decide how many times you will do the experiment.3 Decide how you are going to record the results.

Obtaining evidence4 Choose a suitable shoe and a surface for the experiment.5 Tie the forcemeter to the shoe.6 Pull the shoe without any masses inside it, so that it moves at a

steady speed across the surface.7 Record the force shown on the forcemeter.8 Repeat steps 4 to 7 six times, putting a 100 g mass in the shoe

each time until the mass inside the shoe is 600 g (six masses).Pull the shoe at the same steady speed in each experiment.

Considering the evidence9 Draw a line graph of your results. Put mass along the x-axis and

force up the y-axis.

What happens to the size of force needed to pull the shoe as themass increases?Why do you think this happens? Use the word friction in youranswer.

EvaluatingHow could you improve this experiment?

Shoe soles

2

3

1

Sheet 1 of 1

K2a


ActivityHelp

You going to investigate the relationship between the mass of a shoe and the force needed to pull it against friction.1 You are just going to change the mass of the shoe.

To make it a fair test, the surface, the shoe and the masses need to be kept the same.

2 Tie the forcemeter to the shoe.3 Pull the shoe without any masses

inside it, so that it moves at a steady speed across the surface.

4 Record the force shown on the forcemeter in the table, under Pulling force (1). Check again and record the force under Pulling force (2).

5 Calculate an average for each pull like this: ● add the pulling forces (1) and (2)

together● divide this number by 2● record the answer in the fourth column.

6 Plot the mass of the shoe against the average pulling force on the graph paper below.

What happens to the size of force needed to pull the shoe as the mass increases?

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Why do you think this happens? Use the word friction in your answer.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Shoe soles

Mass in Pulling Pulling Averageshoe in g force (1) force (2) pulling

in N in N force in N

0

100

200

300

400

500

600

Averagepulling force

in N

Mass in shoe in g0 100 200 300 400 500 600

2

1


Running the activityPupils work individually or in pairs to write their story. Pupils can use the ideasprovided on the sheet to help them write their own story.

K2bTeacher

activity notesA world without friction

Paper Pupils develop literacy skills and relate science to everyday life by writing about their Coreimagined experiences if there was no friction.


Sheet 1 of 1

K2b



ActivityCore

Friction is very useful in everyday life. You are going to thinkabout what might happen if there was no friction.

Write a story about life without friction. You can use some of theideas below to help you, or you can use your own ideas.

A world without friction

The day there was no friction

Without friction, cars, buses and bicycles …

When you walk …

It would be very dangerous to be a parachutist because …

Sometimes friction is not useful! Machines …

Heat energy is made when there is friction. This is useful because …

K2bActivity

CoreA world without friction

�

Friction is very useful in everyday life. You are going to thinkabout what might happen if there was no friction.

Write a story about life without friction. You can use some of theideas below to help you, or you can use your own ideas.

The day there was no friction

Without friction, cars, buses and bicycles …

When you walk …

It would be very dangerous to be a parachutist because …

Sometimes friction is not useful! Machines …

Heat energy is made when there is friction. This is useful because …

1

1


Running the activityCore: Pupils work in pairs. They hang weights on a spring and record theextension. They are given a format for a results table. They plot a graph, analysetheir results and evaluate the experiment.

The sheet mentions weights, not masses. The masses provided could be labelled innewtons to avoid confusion if you think this necessary. Alternatively, you mayprefer to ask pupils to add a column to their tables and record first the mass, andthen convert this to weight.

Extension: Pupils hang weights on a spring and then do the same for a rubberband. They are asked to plot separate graphs for the spring and the rubber bandand compare the two graphs.


Expected outcomesPupils plot a graph of extension against weight for a spring and an elastic band, anduse it to infer that there is a relationship between extension and weight. Once theelastic limit of the spring or elastic band is reached, the relationship breaks down.

PitfallsA set of weights 100–600 N has been selected for this experiment, but suitableweights depend on the spring and elastic band chosen. Test the spring and elasticband in advance to find their elastic limit, and choose weights accordingly,changing the weights on the sheet.

Safety notesWear eye protection. Overstretched springs and elastic bands may fly back andcause injury, especially if hooks etc. are still attached. Pupils should take care notto drop weights on their feet.

AnswersCore:

Yes; the greater the weight, the longer the extension, up to a certain weight(the elastic limit).

Suggestion: test springs made of different materials and of different lengths.

Pupils’ own plans.

Extension:

The elastic band stretches more than the spring for a given weight. It breaksmore easily.

Yes; the greater the weight, the longer the extension, up to a certain weight(the elastic limit).

Yes, the greater the weight, the longer the extension, up to a certain weight(the elastic limit).

Suggestions: take another set of results for each/take a set of results whenunloading.

Pupils’ own plans, e.g. test springs made of different materials and of differentlengths.

K3aTeacher

activity notesStretching

Practical Pupils learn the relationship between extension and weight. More able pupils compare Core, Extensionthe extension of a spring with an elastic band.


3

1

2

3

1

2

4

5



EquipmentFor each pair:

Core:

● a spring● a clamp stand with two bosses and clamps● a metre rule● a mass holder● masses from 100 g to 600 g, possibly labelled with their weights in newtons.

Extension:

● as above● an elastic band, about the same length as the spring.

For your informationRunning the activityCore: Pupils work in pairs. They hang weights on a spring and record theextension. They are given a format for a results table. They plot a graph, analysetheir results and evaluate the experiment.

The sheet mentions weights, not masses. The masses provided could be labelled innewtons to avoid confusion if you think this necessary. Alternatively, you mayprefer to ask pupils to add a column to their tables and record first the mass, andthen convert this to weight.

Extension: Pupils hang weights on a spring and then do the same for an elasticband. They are asked to plot separate graphs for the spring and the elastic bandand compare the two graphs.

Expected outcomesPupils plot a graph of extension against weight for a spring and an elastic band,and use it to infer that there is a relationship between extension and weight.Once the elastic limit of the spring or elastic band is reached, the relationshipbreaks down.

PitfallsA set of weights 100–600 N has been selected for this experiment, but suitableweights depend on the spring and elastic band chosen. Test the spring and elasticband in advance to find their elastic limit, and choose weights accordingly,changing the weights on the sheet.

Safety notesWear eye protection. Overstretched springs and elastic bands may fly back andcause injury, especially if hooks etc. are still attached. Pupils should take care notto drop weights on their feet.

K3aTechnician

activity notesStretching

Practical Pupils learn the relationship between extension and weight. More able pupils compare Core, Extensionthe extension of a spring with an elastic band.


Sheet 1 of 1

K3a


ActivityCore

When you hang weights on the end of a spring, the springstretches. A forcemeter has a spring inside it. When you hangweights on the forcemeter, the spring pulls up with a force equalto the force of the weight pulling down. The forces are balanced.You are going to hang weights on a spring and see how much itstretches. This is called the extension.

Obtaining evidence1 Make a table like the one below. You will need six rows.

2 Set up the apparatus as shown in the diagram A.3 Record the position of the base of the spring with a holder but

no weights, in millimetres. This is your zero point.4 Put a 1 N weight on the holder as shown in diagram B.

Record the new position in your table.5 Add weights one at a time and record the positions for 2 N, 3 N,

4 N, 5 N and 6 N.6 Fill in the extension column of your table by subtracting the

zero point from each measurement.

Considering the evidence7 Plot a line graph of your results. Put weight along the x-axis

and extension up the y-axis. Draw a line of best fit using a ruler.

Is there a relationship between the weight on the spring and theamount it extends? Describe the relationship.

EvaluateHow could you make your results more reliable?Plan an experiment to find out if all springs extend in the sameway.

Stretching

Weight in N Position in mm Extension in mm(position – zero point)

A

zeropoint

B

zeropoint

extensionof spring

weight

2

3

1

Wear eyeprotection.

Be careful notto drop

weights on yourfeet.

!

Sheet 1 of 1

K3a


ActivityExtension

When you hang weights on the end of a spring, the springstretches. A forcemeter has a spring inside it. When you hangweights on the forcemeter, the spring pulls up with a force equalto the force of the weight pulling down. The forces are balanced.An elastic band stretches too when you hang weights on it. Youare going to hang weights on a spring and an elastic band andcompare how much they stretch. This is called the extension.

Obtaining evidence1 Make a table like the one below. You will need six rows.

2 Set up the apparatus as shown in the diagram A.3 Record the position of the base of the spring with a holder but

no weights, in millimetres. This is your zero point.4 Put a 1 N weight on the holder as shown in diagram B.

Record the new position in your table.5 Add weights one at a time and record the positions for

2 N, 3 N, 4 N, 5 N and 6 N.6 Fill in the extension column of your table by subtracting

the zero point from each measurement.7 Repeat steps 1 to 6 using an elastic band instead of a spring.

Considering the evidence8 Plot a line graph of your results for the spring. Draw a line of

best fit using a ruler.9 Plot another graph for the elastic band.

How is the extension of the elastic band different from the extension of the spring when you hang weights on them?Is there a relationship between the weight on the spring and the amount it extends? Describe the relationship.Is there a relationship between the weight on the elastic band the amount it extends? Describe the relationship.

EvaluatingHow could you make your results more reliable?Plan an experiment to find out if all springs extend in the same way.

Stretching

Weight in N Position in mm Extension in mm(position – zero point)

A

zeropoint

B

zeropoint

extensionof spring

weight

2

3

4

5

1

Wear eyeprotection.

Be careful notto drop

weights on yourfeet.

!


Running the activityCore/Help: The practical is suggested as a teacher demonstration, although pupilscould carry it out themselves. Use a forcemeter to weigh various objects, first inair and then in water. Ask pupils to observe what happens when the object isimmersed, and elicit the two effects – the weight apparently decreases and thewater level rises. The apparent weight of a floating object is zero. Use the ideas ofbalanced forces to calculate the water’s upthrust on the objects.

Extension: Demonstrate an egg placed in a beaker of water and then placed in thesame volume of very salty water so that the egg floats. Pupils could do this forthemselves, but then use hard-boiled eggs.

Expected outcomesCore, Help: Pupils learn that objects weigh less in water than in air and that for afloating object the weight is balanced by the upthrust. Pupils find that objectsfloat at different levels in different liquids.

Extension: Pupils see that the type of liquid affects how an object floats, not justthe weight of the object.

AnswersCore:

The weight of the object is less in water than in air.

If an object floats, the upthrust equals the weight of object.

Help: Missing words are as follows:

more than

equal to

Extension:

If an object floats, the upthrust equals the weight of object. We know this istrue, because the forces are balanced (the object floats).

Yes

No, the upthrust from the salty water is more than that of tap water.

The type of liquid and the size or density of the object also affects what levelan object will float at.

K3bTeacher

activity notesFloating and upthrust

Practical Pupils watch a demonstration of the weight of objects in air and water, to investigate Core, Help, Extension.upthrust. Extension pupils also compare the upthrust of tap water and salty water.


3

12

1

2

1

2

4


Equipment neededFor demonstration:

● a forcemeter with a scale in newtons suitable to show weights of the chosenobjects

● three or four objects that will float in water, with loops of string attached(make sure they weigh enough to register clearly on the forcemeter in air)

● a trough or large beaker of water, ideally transparent and calibrated, so thatlevel of water can be seen clearly.

For Extension demonstration:

● two large beakers, one containing tap water and one containing the samevolume of very salty water.

For your informationRunning the activityCore/Help: The practical is suggested as a teacher demonstration, although pupilscould carry it out themselves. Use a forcemeter to weigh various objects, first inair and then in water. Ask pupils to observe what happens when the object isimmersed, and elicit the two effects – the weight apparently decreases and thewater level rises. The apparent weight of a floating object is zero. Use the ideas ofbalanced forces to calculate the water’s upthrust on the objects.

Extension: Demonstrate an egg placed in a beaker of water and then placed in thesame volume of very salty water so that the egg floats. Pupils could do this forthemselves, but then use hard-boiled eggs.

Expected outcomesCore, Help: Pupils learn that objects weigh less in water than in air and that for afloating object the weight is balanced by the upthrust. Pupils find that objectsfloat at different levels in different liquids.

Extension: Pupils see that the type of liquid affects how an object floats, not justthe weight of the object.

K3bTechnician

activity notesFloating and upthrust

Practical Pupils watch a demonstration of the weight of objects in air and water, to investigate Core, Help, Extension.upthrust. Extension pupils also compare the upthrust of tap water and salty water.


Sheet 1 of 1

K3b


ActivityCore

You are going to find out about the upthrust of water on anobject when it is lowered into water.

Obtaining evidence1 Watch your teacher weigh the first object.

Record its weight in a table like the one below.2 Now record the weight when the object is in the water.3 Calculate the upthrust of the water on the object.

The weight in air minus the weight in water is the upthrust of the water on the object.

4 You teacher will let go of the object. Record in your table if the object floats or sinks.

5 Record the same information for the other objects your teacher demonstrates.

Presenting the results6 Use a table like this to record your results.

Considering the evidenceWhat happens to the weight of each object in water?Write a sentence to say what you know about the upthrust, ifsomething floats.

Floating and upthrust

5

4

3

2

1

0N

5

4

3

2

1

0N

Object Weight in air Weight in Upthrust in Does it floatin newtons water in newtons or sink?

newtons

2

1

Sheet 1 of 1

K3b


ActivityHelp

You are going to find out about the upthrust of water on an object when it is lowered into water.

Obtaining evidence 1 Watch your teacher weigh the first object. Record its weight in

the table below.2 Now record the weight when the object is in the water.3 Calculate the upthrust of the water on the object like this:

weight of object in air � weight of object in water � upthrust of water

4 Your teacher will let go of the object. Record in your table if the object floats or sinks.


Presenting the results 6 Use this table to record your results.

Considering the evidenceCompare the weight of each object in air and water. Complete this sentence:

The weight of each object in air is .................................................. its weight in water.Compare the weight in water with the upthrust for objects that floated.Complete this sentence:

Objects float when their weight is .................................................. the upthrust of the water.


5

4

3

2

1

0N

Object Weight in air Weight in Upthrust in Does it floatin newtons water in newtons or sink?

newtons

2

1

Sheet 1 of 1

K3b


ActivityExtension

You are going to find out about the upthrust of water on anobject when it is lowered into water, and compare the upthrustof tap water and salty water.

Obtaining evidence 1 Watch your teacher weigh the first

object. Record its weight in a table like the one below.

2 Now record the weight when the object is in the water.

3 Calculate the upthrust of the water on the object.

4 Record in your table if the object floats or sinks.


6 Your teacher will now show you what happens when an object isplaced in tap water and in very salty water. Write down yourobservations of what happens.

Presenting the results 7 Use a table like this to record your results.

Considering the evidenceWrite a sentence to say what you know about the upthrust, ifsomething floats in water. Explain why this must be true.Is the mass of the object the same in tap water and in saltywater?Is the upthrust from the tap water the same as from the saltywater?What else, apart from the weight of an object, affects how anobject will float in a liquid?


Object Weight of Weight of Upthrust Does it floatobject in air object in water in N or sink?

in N in N

2

3

4

1

5

4

3

2

1

0N

5

4

3

2

1

0N


Running the activityAsk pupils to remember the names of forces. Concrete examples of objectshanging, resting on a flat surface, or a tilted book, will help as prompts. List thenames of the forces on the board – weight (not gravity), tension, friction, (drag),upthrust and reaction forces.

Draw some examples and label the balanced forces; or project the diagrams fromthe Core sheet.

Pupils work in groups to label the Resource sheet diagrams. You could ask groupsto add the force labels on the projected version of the Resource sheet, so thecorrect versions can be accepted.

Diagrams A–F on the Resource sheet are easier. Diagrams G–I involve three or fourforces and so are for the most able.

For some groups it may be better to use the projected enlarged versions of thediagrams straight away, then pupils can copy the correct force arrows onto theirsheets.

Other relevant materialResource sheet can be copied on to an OHT slide.

Answers

K3cTeacher

activity notesBalanced forces

Paper Pupils consolidate understanding of situations in which objects are stationary, and the Coreforces are balanced. Pupils practise drawing force diagrams. Resource


weight

weight

1

2


K3cTeacher

activity notesBalanced forces (continued)

A

floating duck

upthrustof water tension

in spring

weightof ball

weight

plasticine ball carrying shopping

B C

D

person in bed

tension in string

Christmas bauble

picture hanging on wall

E F

G

floating boat

book on slope person leaning on wall

H I

forcemeter

upthrustof water

weight

reactionof bed

weightof person

weightweightof book

weight

friction

weightof bauble

friction upslope

friction on floor

reactionof slope

reactionof wall

tensionin arm

weight

tensionin thread

Sheet 1 of 1

K3c


ActivityCore

The forces on an object are balanced when the forces are thesame size and act in opposite directions.You are going to think about how forces balance each other sothat things stay still.

1 Look at the book on the table. It is not falling. There must be a force on it from the table.

The force from the table is the reaction force. It is the same size as the weight. It acts in the opposite direction to the weight.

Sketch the diagram and draw an arrow to show the missingforce.

2 Look at the parachute. Think about the force that balances it so that it floats in air.

Sketch the diagram and draw an arrow to show the missing force.

3 In your group, look at the pictures on the Resource sheet.

Decide what forces are acting. Sketch each picture and drawarrows on the picture to show the size of the forces and theirdirection. Write the names of the forces next to the arrows.

Balanced forces

weight

weight

2

3

1

Sheet 1 of 1

K3c


ActivityResourceBalanced forces

A

floating duck plasticine ball

forcemeter

carrying shopping

B C

D

person in bed Christmas bauble

picture hanging on wall

E F

G

floating boat

book on slope person leaning on wall

H I


Running the activityThe first three demonstrations are appropriate to all Core and Help pupils. Thelast one is for Extension pupils using the Red book. Before each demonstration,explain what you are going to do and ask pupils to predict what they think willhappen. After each demonstration, ask pupils to say what the two unbalancedforces are.

Core, Help:

1 Push a stationary trolley to make it move in the direction of force, showingthat an unbalanced force is needed to make something start moving.

2 Stamp your foot on a can until it first buckles a bit and then squashes, showingthat an unbalanced force can change the shape of an object.

3 Let a trolley already moving run onto a surface with more friction to slow itdown. Push a trolley that is already moving and it speeds up. These show thatan unbalanced force on something moving makes it slow down or speed up.

Extension:

4 Push a ping pong ball so it moves, then blow air at it with a straw from the sideso it moves sideways, showing that an unbalanced force on something makes itchange direction.

Expected outcomesPupils are able to recognise situations in which there are unbalanced forces andwhat effect they have on the objects.

PitfallsIt might be a good idea to test out the demonstrations in advance to check whatworks best.

Safety notesIf large runways are used for trolleys they should be stacked, moved and used withcare especially if they might fall. ‘Catch boxes’ filled with scrap paper, polystyreneetc. should be used when trolleys might fall off the end of tables or runways. Thebox will keep heads and feet out of the ‘drop zone’.

K4aTeacher

activity notesAll unbalanced!

Practical Pupils observe through demonstration the results of unbalanced forces in causing Core, Help, Extensionstationary objects to start moving, objects to change shape, moving objects to speed No pupil sheetsup and moving objects to change direction.



Equipment1 Getting trolley moving:

● a trolley● smooth, flat, level surface● a box containing screwed up paper, for the trolley to crash into.

2 Squashing a can:● an empty soft drinks can.

3 Trolley changing speed:● a trolley● suitable surface – smooth at first and then covered with sand or furry

material● a box containing screwed up paper, for the trolley to crash into.

4 Ball changing direction:● a ping pong ball● smooth, flat, level surface● a box containing screwed up paper, for the trolley to crash into.

For your informationRunning the activityThe first three demonstrations are appropriate to all Core and Help pupils. Thelast one is for Extension pupils using the Red book. Before each demonstration,explain what you are going to do and ask pupils to predict what they think willhappen. After each demonstration, ask pupils to say what the two unbalancedforces are.

Core, Help:

1 Push a stationary trolley to make it move in the direction of force, showingthat an unbalanced force is needed to make something start moving.

2 Stamp your foot on a can until it first buckles a bit and then squashes, showingthat an unbalanced force can change the shape of an object.

3 Let a trolley already moving run onto a surface with more friction to slow itdown. Push a trolley that is already moving and it speeds up. These show thatan unbalanced force on something moving makes it slow down or speed up.

Expected outcomesPupils are able to recognise situations in which there are unbalanced forces andwhat effect they have on the objects.

PitfallsIt might be a good idea to test out the demonstrations in advance to check whatworks best.

Safety notesIf large runways are used for trolleys they should be stacked, moved and used withcare especially if they might fall. ‘Catch boxes’ filled with scrap paper, polystyreneetc. should be used when trolleys might fall off the end of tables or runways. Thebox will keep heads and feet out of the ‘drop zone’.

K4aTechnician

activity notesAll unbalanced!

Practical Pupils observe through demonstration the results of unbalanced forces in causing Core, Help, Extensionstationary objects to start moving, objects to change shape, moving objects to speed No pupil sheetsup and moving objects to change direction.



Running the activityPupils work individually or in pairs to answer the questions on the sheet.

Core: Pupils should use the force diagrams on the sheet for question 1 as a guideto drawing force diagrams for questions 2 and 3.

Extension: Pupils draw force diagrams, and also calculate the resultant force towork out in which direction the object will move.

AnswersCore:

A – unbalanced (bicycle moving slower); friction force from the brakes on thetyres

B – unbalanced (orange team is winning); pulling force from the orange teamis greater than the pulling force from the yellow team

K4bTeacher

activity notesUnbalanced forces

Paper Pupils reinforce learning of the effects of unbalanced forces on an object, and practise Core, Extensiondrawing force diagrams.


friction/air resistance

force ofengine

friction force ofhand

friction

friction

weight

forceof hand

friction

reactionforcefromcan

3

1

2

4


Extension:

Orange team

100 N

The cart moves forwards.

500 N, in the direction of the elephant’s pull

The trolley veers to the left.

K4bTeacher

activity notesUnbalanced forces (continued)

400 N 300 N

1500 N 2000 N

friction

Mark pushes fromthe side

Janepushing

originalpath

of trolley

pathof trolley

when Markpushes from

side

4

1

2

5

3

Sheet 1 of 1

K4b


ActivityCore

Unbalanced forces make things start to move, move faster, moveslower or change their shape. You are going to answer somequestions about unbalanced forces.

1 Look at the diagram of a skateboard. It is being pushed fromstanding still. The foot on the ground is pushing with a force that is bigger than friction.

Sketch the diagram and draw an arrow to show the force fromthe foot.

2 Look at foot crushing the can. Think about the force that will make it change its size and become smaller.

Sketch the diagram and draw an arrow to show the missing force.

Look at the situations below. For each one, write down whetheran unbalanced force is acting. If so, explain where it comes from.

Friction is a force that stops things moving, or slows them downwhen they are moving. Friction acts in the opposite direction to themovement. If you want to start something moving, or speed it up,you need a force larger than friction.

For each of the following, draw a diagram with force arrows.Show the force making the movement and the friction force. ● a car driving along● a person opening a drawer● you sliding down a rope● a shopper pushing a trolleyDraw a picture of a game of tennis or rounders. Add arrows toshow all the unbalanced forces.

Unbalanced forces

A Bbicyclescreechingto a halt

yellowteam

orangeteam winning

Remember– the longer thearrow the larger

the force.

2

3

4

5

1 friction

reactionforcefromcan

Sheet 1 of 1

K4b


ActivityExtension

Unbalanced forces make things start to move, move faster, moveslower or change their shape. Unbalanced forces can also makemoving objects change direction.You are going to find out the sizes of the forces in the questionsbelow.

Who will win the tug-of-war? What is the size of the unbalanced force?

A horse pulls a cart with a force of 400 N. There is a force of friction on the cart’s wheels of 300 N.

Draw a force diagram and say what happens to the cart.

A team of circus trainers is pulling an elephant. The trainers pull with a force of 1500 N. The elephant pulls back with a force of 2000 N.

Draw a force diagram to show the forces on the trainers and elephant. Calculate the size of the unbalanced force. Which way will they all move?

Jane is pushing the shopping trolley in a straight line towards the car. But Mark is hanging on the side and pushing forwards from his position. Draw a force diagram to show what direction the trolley will move in.

Unbalanced forces

yellowteam

orangeteam

200 N 300 N

Mark pushes fromthe side

Janepushing

originalpath

of trolley

2

3

4

5

1


Running the activityThe Core sheet is to support average ability pupils using the Red book. TheExtension sheet is more challenging.

Pupils work through the questions on the sheet in order. The last questions onboth sheets are more challenging.

Other relevant materialsSkill sheet 6: Interpreting graphs

AnswersCore:

5

1 km

3 minutes, e.g. to buy sweets or meet a friend

5

2 km

2 minutes

10

8 km

1/5 or 0.2 km/min

10/25 � 0.4 km/min

Extension:

15 minutes

Sam stopped twice. First, e.g. to buy sweets or meet a friend. Second to waitfor the bus.

2 km

10

8 km

1/5 or 0.2 km/min

8/10 or 0.8 km/min

60 � 0.8 � 48 km/h

10/25 � 0.4 km/min

A rising line but not as steep as the bus line

K5aTeacher

activity notesSchool journey

Paper Pupils interpret distance-time graphs Core, Extension


3

8

9

12

4

56

7

10

3

8

9

12

4

56

7

10

Sheet 1 of 1

K5a


ActivityCore

You are going to use a distance-time graph to describe Sam’sjourney to school.

Sam walks to the bus stop, then catches a bus. On the way to thebus stop Sam stops for a few minutes.

How many minutes does Sam walk for, before stopping the firsttime?How far away from home does Sam stop the first time?How many minutes does Sam stop for? Suggest why Sam mightdo this.How many more minutes must Sam walk before reaching the busstop?How far away from Sam’s home is the bus stop?How long does Sam wait for the bus?How many minutes does the bus ride take?How long is the bus ride, in kilometres?Calculate Sam’s walking speed during the first 5 minutes, inkilometres per minute.Calculate Sam’s average speed for the total journey in kilometresper minute.

School journey

Distancein kilometres

00

Time in minutes

5 10 15 20 25 30

2

4

6

8

10

12

2

3

4

5

6

7

8

9

10

1

Sheet 1 of 1

K5a


ActivityExtension

You are going to use a distance-time graph to describe Sam’sjourney to school.

Sam walks to the bus stop, then catches a bus. On the way to thebus stop Sam stops for a few minutes.

How long is it before Sam catches the bus?There are two periods on the graph where the line is horizontal.What does this show about Sam’s journey? Suggest what Sam isdoing for each of these two periods.How far away from Sam’s home is the bus stop?How many minutes does the bus ride take?How long is the bus ride, in kilometres?Calculate Sam’s walking speed during the first 5 minutes, inkilometres per minute.Calculate the bus speed in kilometres per minute.Calculate the bus speed in kilometres per hour.Calculate Sam’s average speed for the total journey in kilometresper minute.The graph stops at the end of Sam’s bus journey. Assume Samgets off the bus and walks straight to school without stopping.Describe the line you would draw on the graph to show this.

School journey

Distancein kilometres

00

Time in minutes

5 10 15 20 25 30

2

4

6

8

10

12

2

3

4

5

6

7

8

9

1

10

K1


PlenariesForces and gravity

Sheet 1 of 1

Review learning● Pupils give one example of how each of the forces

(see right) is useful in everyday life.

● Ask them to say if the forces in their examples are forcesof attraction or repulsion.

Sharing responses● Pupils prepare OHT slides of their mass/weight graphs

(Activity K1a).

● Compare pupils’ graphs and discuss similarities anddifferences in the data collected from each group – dothis by overlaying two OHTs to show that the generalshape of the graphs is similar but that the angle of slopemay vary due to the scale chosen by the group.

● Point out any data errors that show up in the graph,and discuss the reasons for these.

Group feedback● Pupils who carried out Extension Activity K1b describe

the relationship between weight and gravity on theMoon, and how they used this relationship to work outtheir answers to the questions.

● Pupils discuss in pairs their response to questions 9(space shuttle) and 10 (Mars probe).

● Summarise ideas for responses to question 10 onOHT/board. Compare their suggestions. What is thescience that NASA is depending upon?

Word game● Pupils look at the lists of three words on the board

(see right) and write down the odd one out.

● Individual pupils justify their choice.

Looking ahead● Set the questions on the right for individuals to consider

and suggest answers to.

● Pupils then share responses with each other. Make itclear they may not know the answer and need tosuggest their ideas and predictions.

● Suggestions can be summarised and recorded in pupils’books to reconsider after further lessons.

Review learning Sharing responses Group feedback Word game Looking ahead

Suggested alternative plenary activities (5–10 minutes)

Pupils give examples ofhow five forces are usefulin everyday life.

Pupils share responsesfrom Activity K1a.

Pupils share feedback onActivity K1b (Extension)

Pupils identify the oddone out in lists of words.

Pupils suggestconsequences of changes tothe Earth’s gravity.

Forcesfrictiongravityelasticitymagnetismair resistance

Listsweight, mass, gravitykilograms, grams, newtonsair resistance, friction, magnetism

QuestionsWhat would happen if the Earth’s gravity:(a) doubled?(b) halved?(c) remained the same but only affected

the southern hemisphere?

K2


PlenariesFriction

Sheet 1 of 1

Review learning● Pupils work in pairs to write three reasons to prove or

disprove the statement (see right).

● List their suggested reasons on the board. Pupils can sayif they support a reason offered or wish to challenge it.Both supporters and challengers justify their position.

Sharing responses● Pupils work in pairs to present and summarise their

ideas for Activity K2b (A world without friction) onPowerPoint/OHT.

● Draw out and summarise ideas from the groups. Use their suggestions to identify features of friction, and scientific vocabulary used.

Group feedback● Each group/pair summarises what their data for Activity

K2a suggests for a relationship between the mass of ashoe and the force needed to pull it against friction.

● Summarise these suggestions on the board and check ifall groups suggesting the same idea.

● Compare the strategies used to collect the data from thedifferent groups. Check if any differences in conclusioncould be due to different methods.

Word game● Pupils work in pairs to write down five questions about

friction on small cards, with the answer at the bottomof each card.

● Collect and shuffle all the cards, then deal each pair fivecards (or three, depending on time). Pupils take turns toask the new questions to their partner.

● Carry out a class scan to avoid any incorrect answersbeing provided.

● Alternatively, use the cards as a quiz at the beginning ofthe next lesson.

Looking ahead● Ask pupils to think of ways in which they could make a

model of how a lubricant reduces the force of friction.You may need to suggest a list of equipment to get them started.

● Pupils write a description and draw diagrams of theirmodel set-ups.



Pupils list reasons to proveor disprove a statement.

Pupils share their writtenwork from Activity K2b.

Pupils prepare a sentenceto summarise theirfindings in Activity K2a.

Pupils generate fivequestions and answers onsmall pieces of card.

Pupils suggest ways tomodel how a lubricantreduces the force offriction.

StatementYou cannot go on holiday without a force –prove it!

K3


PlenariesBalanced forces

Sheet 1 of 1

Review learning● Pupils label the diagrams of balanced forces on the pupil

sheet with the name of the force and an arrow showingthe direction of the force.

● Pupils should also be encouraged to discuss the size ofthe arrows they are drawing.

Sharing responses● Pupils compare similarities and differences between

their data and conclusions for Activity K3a (Stretching).

● Ask them to predict what they would expect if they usedbigger/smaller springs (and elastic bands).

Group feedback● Working in pairs, pupils draft out a statement to explain

why different objects float or sink in water.

● With the whole class, refine the statement so all agreewith it.

● Extension pupils can then draft a statement comparinghow objects float in tap water and salty water.

Brainstorming● Pupils work in pairs to think of some situations in

everyday life in which there are balanced forces.

● Ask them to compare their ideas with another pair, andcheck and justify their choices.

Looking ahead● Explain that buoys are anchored to the seabed or sea

wall at the base on a long chain. They are made ofmaterial that allows them always to float at the surface.The chain length allows them to adjust their heightabove the seabed as the tide changes.

● Pupils work in pairs to decide what forces might be atwork. Encourage pupils to summarise ideas in drawingsusing force arrows.

Review learning Sharing responses Group feedback Brainstorming Looking ahead


Pupils label diagramsinvolving balanced forces.

Pupils share their resultsand responses from Activity K3a.

Pupils discuss their resultsfrom Activity K3b.

Pupils think aboutsituations in everyday lifein which there arebalanced forces.

Pupils apply their ideas offorces to describe howbuoys float on the sea.

➔ Pupil sheet


Review learningLabel each diagram with:● the names of the forces acting● arrows to show the directions in which the forces are acting.

K3 PlenariesBalanced forces

A

B

C

D

E

K4


PlenariesUnbalanced forces

Sheet 1 of 1

Review learning● Pupils work on their own to draw diagrams showing the

situations listed on the right.

● Draw the correct diagrams on the board or ask pupils toswap diagrams with a partner and discuss.

Sharing responses● Pupils compare their predictions with what happened in

the teacher demonstrations (Activity K4a). Check ifthere were any surprises.

● Ask pupils to say what the two forces are and which isthe larger force in each example.

Group feedback● Individually, pupils write down one point they have

learnt in the lesson about unbalanced forces. Then theypair up with a partner and share their points. Finally,they pair up with another pair and compare theirpoints.

● Everyone should be prepared to share at least one pointwith the whole class.

Word game● Read out the statements on the Teacher sheet and let

pupils work in pairs or alone to decide if the statementsare true or false.

Looking ahead● Pupils brainstorm everyday situations in which the

word ‘speed’ is used.

● List all the suggestions on the board.

● Ask pupils to use the examples to help them write adefinition for the speed of a moving object.

● With the whole class, refine the statement so all agreewith it. Make sure it includes distance and time taken.



Pupils draw diagrams toshow situations in whichthe forces are unbalanced.

Pupils compare theirpredictions with whathappened in Activity K4a.

Pupils write down whatthey have learnt from thelesson and share this witha partner, and then withanother pair.

Check progress using atrue/false quiz on work sofar in the unit.

Pupils discuss a definitionfor the speed of a movingobject.

SituationsGetting a motionless football/ice puck tomove.A crane picking up a load from the floor.A car that is travelling faster and faster.

➔ Teacher sheet


Word gameRead out the statements below and ask pupils to answer true or false.

1 You need friction to help you stop on skis. [True]

2 Friction is always helpful. [False]

3 When an object is still, there are no forces acting on it. [False]

4 Gravity only exists on Earth, not other planets. [False]

5 Gravity is a force of attraction. [True]

6 Mass describes the amount of stuff in something. [True]

7 Your mass will remain constant regardless of where in theuniverse you are. [True]

K4 PlenariesUnbalanced forces

K5


PlenariesSlow down!

Sheet 1 of 1

Review learning● Pupils match each set of distance–time data on the Pupil

sheet with a situation described there.

● Ask individual pupils to share their answers and justifythem.

Sharing responses● Pupils use their answers to Activity K5a to write a

description of the school journey.

● They share this in pairs/groups and check anysimilarities and differences.

● Ask pupils to discuss why the graph is drawn throughthe origin and if all distance–time graphs pass throughthe origin.

Group feedback● Ask pupils to think about what scientific ideas and

vocabulary they need to use to communicate aboutstopping distances to the driving school students.

● Ask them to consider what are the key messages to putin the poster.

● They draw their posters and compare them and see ifthey have all included the same key messages.

Word game● Pupils write a short poem about speed using a

writing frame.

● Examples of similar poems about friction are given as a guide.

Looking back● Pupils revise and consolidate knowledge from the unit.

They can use the Unit map, Pupil check list, or the Testyourself questions.

Review learning Sharing responses Group feedback Word game Looking back


Pupils match sets ofdistance-time data tosuitable situations.

Pupils share descriptionsof their distance-timegraphs from Activity K5a.

Pupils make a poster toexplain to driving schoolstudents what stoppingdistance is.

Pupils write a short poemabout speed using keywords.

Pupils revise andconsolidate knowledge fromthe unit.

➔ Pupil sheet

➔ Pupil sheet

➔ Unit map➔ Pupil check list➔ Test yourself


Review learningMatch these distance–time graphs with the situations they describe.

K5 PlenariesSlow down!

A

30

30

Distancein metres

Time in minutes60 90 120

C 6

Distancein metres

Time in seconds200

B

0 1 2 3 4 5 6

180

Distancein metres

Time in hours

A child sliding

down a

playground

slide

A capsule onthe ‘London Eye’big wheel overseveral hours

A cyclist on

one stage of the

‘Tour de France’

race


K5 Plenaries


K5 Plenaries

�

Word gameHere is a short poem about friction:

Write a similar poem about speed. Use the writing frame to help you.

Slow down!

FrictionRubbing surfacesSlows you downUseful when driving carsMakes you stop when braking

Line 1 Write one word to name the concept. Speed

Line 2 Write two words to describe speed.

Line 3 Write three words to explain what speed does.

Line 4 Write four words to describe how you feel about speed.

Line 5 Write five words to describe an everyday use of speed.

Word gameHere is a short poem about friction:

Write a similar poem about speed. Use the writing frame to help you.

Slow down!

FrictionRubbing surfacesSlows you downUseful when driving carsMakes you stop when braking

Line 1 Write one word to name the concept. Speed

Line 2 Write two words to describe speed.

Line 3 Write three words to explain what speed does.

Line 4 Write four words to describe how you feel about speed.

Line 5 Write five words to describe an everyday use of speed.

K6


PlenariesArchimedes’ story – Thinkabout

Sheet 1 of 1

Group feedback● Pupils discuss how they might have tackled the King’s

problem with the crown and worked out if he had beencheated.

● Ask pupils what examples in everyday life they canthink of that are similar to the King’s problem. Whatstrategies would they use?

● Explain that they need to use a combination of theireveryday experience and what they know about scienceto solve problems like this, as scientists do.

Bridging to other topics● Pupils will have further chances to think about how

scientists work in other units.

Group feedback Bridging to other topics

Pupils discuss how they might have Pupils will have other opportunities totackled the King’s problem. see how scientists work in other units.


Examples7G The particle model8I Density in heating and cooling9J The way gravity holds the solar system

together

K1


SpecialsForces and gravity

1 Look at these forcemeters (newtonmeters). Each is measuring a different force in newtons (N).

a Fill in the force each forcemeter is measuring.

b Which of these forces is the biggest? ......................... N

c Which of these forces is the smallest? ......................... N

2 Match the words to the descriptions.

Sheet 1 of 2

Force � .............. N Force � .............. N Force � .............. N Force � .............. N

A0

1

2

3

4

5

B0

1

2

3

4

5

C0

5

10

15

20

25

D0

5

10

15

20

25

force

weight

mass

gravity

newtons (N)

kilograms (kg)

The pull of the Earth’s gravity on something.

A push or a pull.

Weight is measured in these.

The units of mass.

The force that makes something fall to the ground.

How much stuffsomething is made of.

K1


SpecialsForces and gravity (continued)

3 Look at this table. It contains information about the weight and mass of some items.

Write true or false for each sentence.

a Mass is measured in kilograms. .........................

b Weight is measured in kilograms. .........................

c Weight is caused by gravity pulling down on a mass. .........................

d There are 10 Newtons in 1 kilogram. .........................

Look at the table.

e Which item has a mass of 10 kg? ...........................................................................

f Which item has a weight of 100 N? ...........................................................................

g Which item has the smallest mass? ...........................................................................

h Which item has the smallest weight? ...........................................................................

i Which item has the largest weight? ...........................................................................

j Which item has the largest mass? ...........................................................................

k James has a smaller / larger mass than Janine.

l Janine weighs more than / less than James.

Sheet 2 of 2

Underlinethe right words.

Cross out thewrong words.

Item Mass Weight in kg in N

James 47 470

large book 1 10

bag of sugar 2 20

bag of potatoes 10 100

Janine 53 530

K2


SpecialsFriction

1 Match the words to the descriptions.

Sheet 1 of 1

2 a Draw a circle around the shoes or boots you think would be best for walking on icy pavements.

b Write one or two sentences about what kind of shoes or boots wouldbe best. Use some of these words to help you.

The best shoes for walking on icy pavements have .................................................................

because ..................................................................................................................................................................................

slipbrightly coloured

smooth soles

bumpy soles good grip

lots of friction

little friction

friction

rough surface

lubricant

smooth surface

Has lots of friction.

A force that happens when things rub against each other. It stops things moving easily.

Lets moving parts slideeasily past each other.

Has little friction.

K3


SpecialsBalanced forces

1 Use these words to fill the gaps.

a If the forces are ...................................... an object will not move.

b Balanced forces are the same size and pull in

...................................... directions.

c When you put an object in water, the ......................................

pushes upwards on the object. This push is called

.......................................

d If the upthrust on an object is the same size as its

weight, the object will ...................................... .

2 This balloon is floating in the air. Look carefully at the diagram.

Which arrow shows the upthrust? Circle the arrow.

Sheet 1 of 2

weight

balancedwater oppositefloat

upthrust

K3


SpecialsBalanced forces (continued)

3 Look at these diagrams. The arrows show the size anddirection of the forces.

a In which diagrams are the forces balanced? ......................................

b Will the boat float or sink? ......................................

c The jug is standing on a table. The weight of the jugis the same size as the reaction force of the table.Label the forces in diagram D.

Sheet 2 of 2

A B

C D

K4


SpecialsUnbalanced forces

2 Use these words to fill the gaps.

a If one force on an object is bigger than another, the

forces are ................................................. .

b When unbalanced forces act on an object it starts to

...................................... in the direction of the ......................................

force. It gets ...................................... .

c If the bigger force is in the same direction as the object

is moving, the object .............................................................................

d If the bigger force is opposite to the direction the object

is moving, the object ............................................................................ .

Sheet 1 of 2

1 Match the words to the sentences.

move faster

bigger

gets faster

slows down unbalanced

friction

air resistance

unbalanced

These forces make somethingmove faster or slower.

This force slows things down when they move through the air.

This force acts when two things rub together.

K4


SpecialsUnbalanced forces (continued)

3 Look at these diagrams. The arrows show the forces acting on the cars.

Use words from the diagrams to fill in the gaps.

a ............................................................................ is a type of friction force,

caused by the car moving through the air.

b The force of the ...................................... is in the opposite direction

to the .............................................................................

c ...................................... is the force acting when the driver applies

the brake.

Use A, B or C to answer these questions.

d In which car are the forces balanced? .......................

e Which car is travelling at a steady speed? .......................

f In which car is the engine force bigger than the friction? .......................

g Which car is getting faster? .......................

h Which car is slowing down? .......................

Sheet 2 of 2

A B

C

airresistance

forceof engine

airresistance

forceof engine

frictionand airresistance

forceof engine

The distance a cartravels while the car slows

down and stops.

K5


SpecialsSlow down!

1 Use high or low to fill in the gaps.

a If you travel a long distance ina short time then your speed is ........................ .

b If you travel a short distance ina long time then your speed is ........................ .

2 Look at these words and units.

a Draw lines to match the words to the units.

b Colour the words and units used to measure speed.

3 a Match the words to the descriptions.

b As a car moves faster, the stopping distancegets smaller / stays the same / gets bigger.

Sheet 1 of 2

Circle theright words.Cross out thewrong words.

thinking distance braking distance stopping distance� �

km

s

m/s

km/h

m


down and stops.

The distance a car travelswhile

the car slows down andstops.

The total distance a cartravels while the driver

thinks, brakes and bringsthe car to a stop.


down and stops.

The distance a car travels while

the driver decides to brake.

kilometres per hour

metres per second

kilometres

seconds

metres

K5


SpecialsSlow down! (continued)

4 Look at the speeds of these different things. Use themto answer the questions.

a What is a cheetah’s speed? ......................... m/s

b What has a speed of 45 m/s? ......................................

c What is the slowest thing? ......................................

d What is the fastest thing? ......................................

e If you were a top sprinter and were being chased by

a T. rex, could you out run it? .........................

Why do you think that?

Because .............................................................................................................................

.......................................................................................................................................................

Sheet 2 of 2

top sprinter10 m/s

T. rex15 m/s

fast car45 m/s

airplane200 m/s

cheetah27 m/s

K6


SpecialsArchimedes’ story

Gareth and Lisa are arguing about which object has the biggest volume.

Gareth thinks the cube is biggest.Lisa thinks the cylinder is bigger.

1 They do an experiment to find out which objecthas the biggest volume. This is what they do.

a The instructions are all mixed up! Match the instructions to the pictures.

b What is used to measure the volume of water?

.......................................................................................................................................................

2 Look at the results in the table.

a Which object hasthe largest volume? ..........................

b Which object hasthe smallest volume? ..........................

c The best way of finding the volume of an object is by measuring / guessing.

Sheet 1 of 1

cube

sphere cylinder

rock

A B C

Volume ismeasured

in cm3

Object Volume in cm3

cube 125

sphere 100

rock 149

cylinder 136

Fill the can withwater and wait

until it stopsdripping.

Put a measuringcylinder under

the spout.

Slowly put the object intothe can. Collect all the

water that comes out inthe measuring cylinder.

K1 Forces and gravity1 a 3N, 2N, 12N, 13N

b 13Nc 2N

2 force – A push or a pull.weight – The pull of the Earth’s gravity onsomething.mass – How much stuff something is made of.gravity – The force that makes something fall tothe ground.newtons (N) – Weight is measured in these.kilograms (kg) – The units of mass.

3 a true b false c true d truee bag of potatoes f bag of potatoesg large book h large booki Janine j Janinek smaller l more than

K2 Friction1 friction – A force that happens when things rub

against each other. It stops things movingeasily.rough surface – Has lots of friction.lubricant – Lets moving parts slide easily pasteach other.smooth surface – Has little friction.

2 a A circle should be drawn around the walkingboot.

b Correctly reasoned sentence.

K3 Balanced forces1 a balanced b opposite

c water, upthrust d float2 The arrow at the very top of the balloon should

be circled.3 a B, C, D b float

c Arrow pointing up is reaction force, arrowpointing down is the weight.

K4 Unbalanced forces1 air resistance – This force slows things down

when they move through the air.friction – This force acts when two things rubtogether.unbalanced – These forces make somethingmove faster or slower.

2 a unbalanced b move, bigger, fasterc gets faster d slows down

3 a air resistanceb engine, air resistance (or air resistance,

engine) or friction, engine (or engine, friction)c friction d C e Cf A g A h B

K5 Slow down!1 a high b low2 a kilometres per hour – km/h

metres per second – m/skilometres – kmmetres – mseconds – sb Kilometres per hour, metres per second,

km/h and m/s coloured.3 a thinking distance – The distance a car travels

while the driver decides to brake.braking distance – The distance a car travelswhile the car slows down and stops.stopping distance – The total distance a cartravels while the driver thinks, brakes andbrings the car to a stop.

b gets bigger4 a 27 m/s

b fast carc top sprinterd airplanee nof the T. rex can run faster than the top

sprinter

K6 Archimedes’ story1 a A – Fill the can with water and wait until it

stops dripping.B – Put a measuring cylinder under the spout.C – Slowly put the object into the can.Collect all the water that comes out in themeasuring cylinder.

b measuring cylinder2 a rock b sphere c measuring

K Specials answersForces and their effects


Sheet 1 of 2

K1


Homework

HELP1 The sentences below all have mistakes in them. Rewrite them,

correcting the mistakes.

a Sally stood on some bathroom scales and measured her mass innewtons.

b A tennis ball always comes back to Earth because gravity ispushing up on it.

c Weight is the force of gravity acting on an object and ismeasured in kilograms.

2

Use this information to help you copy and complete the table.

CORE3 Here are three words about forces. Write a sentence for each one,

using the word with its correct, scientific meaning.

a weight b gravity c mass

4 Solve these problems. Show how you worked out the answers.

a Joe is standing on some normal bathroom scales and the dialreads 86 kg. What is his weight in newtons?

b Sukinder is standing on some special scales and the dial reads540 N. What is Sukinder’s mass?

Forces and gravity

Anita has a mass of 50 kg. To find her weight (on Earth) you multiply her mass �10. So Anita weighs 50 � 10 � 500 N.

Rashid weighs 660 N. To find his mass you divide his weight � 10. So Rashid’s mass is 600 � 10 � 66 kg.

Object Mass in kilograms Weight in newtons

a bag of shopping 8

a full suitcase 17

an estate car 12 100

K1


HomeworkForces and gravity (continued)

EXTENSION5 a A well-travelled, intergalactic space car has a mass of 900 kg.

The table shows its weight on the Earth and its weight on theMoon.

Write two or three sentences explaining why its mass is thesame in both places, but its weight is different.

b The space car lands on some other planets. Copy and completethis table.

Sheet 2 of 2

Earth Moon

Mass in kg Weight in N Mass in kg Weight in N

900 9000 900 1500

Planet Size of gravity Mass of car Weight of car compared to Earth in kg in N

Earth 1 900 9000

Jupiter 2.5 900

Venus 0.9 8100

Mercury 900 3600

Deep Space 0 0

K2


HomeworkFriction

HELP1 Copy and complete these sentences using the words below.

a When John rides his bike he stops it by applying the ...................................... .

These press onto the front ...................................... . The force that stops the

bike is called ...................................... .

b On John’s skateboard there are no brakes. The only friction is

between the ...................................... and the ...................................... .

2 There is friction between a moving object and the air. Gravity isthe force that pulls an object down to the Earth.

On each of these diagrams, one arrow (A or B) representsfriction and the other arrow represents gravity.

Copy and complete the table, using A or B. The first one has been done for you.

Sheet 1 of 3

ground wheel brakes friction wheels

A

AA

B

B

B

Object Friction Gravity

falling tennis ball B A

horse pulling a cart

rocket leaving the launch pad

K2


HomeworkFriction (continued)

CORE3 There is friction between a moving rocket and the air. Think about

the type of energy given out where there is friction.

What will happen to the temperature of the rocket nose cone as itmoves through the air? Explain your answer.

4 Sandy’s car is in the garage for a service.

a Name one feature of the car that is designed to increasefriction.

b Would wider tyres increase or reduce friction? Explain youranswer.

c A mechanic is putting oil into the engine. What is its purposeand how does it work?

d If Sandy drove her car home with the boot lid open, why wouldfriction be higher than usual?

Sheet 2 of 3

K2


HomeworkFriction (continued)

EXTENSION5 Captain Calamity has run his yacht aground on a sandbank near

the harbour. He tries to pull it off with a winch and finds that theforce needed to move it changes as the tide comes in.

The table shows the force needed to just move the yacht whenthe water is at different depths.

a Plot a graph of the data. Put the depth of water along thebottom, and the force needed to just move the yacht up theside. Choose the type of graph you think is best. You can use aspreadsheet if you wish. Do not forget the labels.

b Use the graph to describe how the force needed to just movethe yacht changes as the tide comes in.

c Why do you think the graph is not a straight line?(Hint: think about the shape of the underneath of a yacht.)

Sheet 3 of 3

Geniusbonus

question!

Depth of water Force needed to justin cm move the yacht, in N

0 20 000

5 19 800

10 19 500

15 19 000

20 18 600

25 17 900

30 17 000

35 15 800

40 14 000

45 11 000

50 4 000

K3


HomeworkBalanced forces

HELP1 Look at diagrams A to E. Each has two force arrows, drawn in

opposite directions.

For three of the objects the forces are balanced. Write down theletters of the three objects.

2 Carly’s dog always pulls hard on its lead when she takes it for awalk. On one walk, the dog pulled on the lead with a force of250 N. Carly pulled on the lead with a force of 250 N.

a Draw a diagram of Carly and her dog. Add the two pullingforce arrows to your diagram.

b Explain why neither the dog nor Carly began to move.

Sheet 1 of 2

A

C

D

E

B

K3


HomeworkBalanced forces (continued)

CORE3 Here are diagrams of the same sailing boat floating in three

different types of water.

a In which kind of water is the upthrust greatest?

b Explain how you can tell this from the diagrams.

c When the boat in diagram B has several people in it, it looksmore like the boat in diagram C. Explain why this is so.

d What will happen to the boat in diagram A if a passengerjumps over the side?

EXTENSION4 The diagram shows a firework rocket, just after it has left the

ground on bonfire night. Three seconds after lift-off it is movingupwards at a steady speed.

a Copy the diagram, then add the following force arrows:i weight ii friction iii upthrust.

b What will happen to the upthrust, as the chemicals inside therocket begin to run out?

c What can you say about the upthrust and the total downwardforces, when the rocket is travelling at a steady speed?

At the end of its upward flight the rocket stops going up andbegins to fall.

d Draw the diagram again to show the directions and sizes of theweight and friction force arrows, when it is falling at a steadyspeed. Label both arrows.

Sheet 2 of 2

A B C

normal sea water Dead Seasea water

fresh water

K4


HomeworkUnbalanced forces

HELP1 These three sentences have been cut in half and mixed up. Match

the start of each sentence (on the left) to its ending (on the right).Then write down the three correct sentences.

2 Ben tries to push a large box along the floor. The diagram showsthe forces acting on the box. The length of each arrow shows thesize of the force. 1 cm represents 10 N.

a Copy the box. Label the box A.Ben pushes box A with a 20 N force. The friction force is 20 N. Draw force arrows of the correct length on your diagram.

b Draw another box. Label this box B. Add force arrows for a push of 40 N and friction of 30 N.

c Which of the boxes will move, A or B? Explain why.

Sheet 1 of 3

2 cm

friction20 N

pushingforce 10 N

1 cm

To make an object begin to move …

… the pushing force and the friction force are balanced.

To move an object to the right …

… the forces acting on it must be unbalanced.

Once an object is moving at a steady speed …

… you must push it to the right.

K4


HomeworkUnbalanced forces (continued)

CORE3 A skydiver jumps from a plane. She is falling towards the Earth.

The diagram shows her falling.

a What do we call force A?

b What do we call force B?

c Copy and complete these sentences.

At first, the skydiver speeds up as she falls towards the Earth. This

is because force A is ...................................... than force B.

Eventually, the skydiver stops accelerating. This happens when

force A and force B are .......................................

d When the parachute opens, the skydiver falls at a steady speed.Draw a diagram to show this. Include arrows for the twoimportant forces that control her speed.

e Are the two force arrows you have just drawn the same size ordifferent sizes? Explain your answer.

Sheet 2 of 3

A

B

K4


HomeworkUnbalanced forces (continued)

EXTENSION4 a Calculate the size of the resultant force for each of the following

situations. Show all your working.i The force produced by a car engine is 1500 N and the air

resistance is 55 N.ii Your school’s tug-of-war team pulls with a maximum force

of 800 N. Your teachers’ team can only pull with amaximum force of 675 N.

iii The weight of a container is 15 000 N. A crane tries to pull itupward with a force of 12 400 N.

b In one of the situations above there will be no movement. Saywhich it is and explain why there will be no movement.

5 Each of these diagrams says whether the object was stationary ormoving before the forces were applied.

Work out what will happen to each object and explain why.

Sheet 3 of 3

A100 N 150 N

10 000 N

15 N

100 N85 N

The car was travelling at 50 km/h.

50 N 100 N

The crate was stationary.

The yacht was moving slowly up the beach.

The diver was falling10 m every second.

The arrow was stationary.

B

D

E

C

10 000 N

1000 N

K5


HomeworkSlow down!

HELP1 This bar chart shows the maximum speeds of various things that

move.

a What is the maximum speed of the thing powered with petrol?

b Which is the slowest thing and how fast does it travel?

c Which thing is twice as fast as a cyclist?

2 John and James walk to school together every day. The distancefrom home to school is 2 km. They decide to have a race. John canrun at 5 m/s and James can run at 4 m/s.

a Who will get to school first?

b Explain how you know this.

Sheet 1 of 3

snail

0.01

human

10

110

0.3

220

340

cyclist sloth cheetah car

Things that move

0

50

100

150

200

250

300

350

400

Max

imum

sp

eeds

in m

/s

K5


HomeworkSlow down! (continued)

CORE3 This question is about stopping a car. Remember that a car travels

some way before the driver manages to put on the brakes. This iscalled the thinking distance. The car then goes even furtherwhile the brakes bring the car to a halt. This is called the brakingdistance.

The table gives some information about the thinking and brakingdistances for the same car at different speeds.

a What is the total stopping distance of a car travelling at 45 km/h?

b A child runs into the road 45 m in front of a car travelling at80 km/h. Will the car hit the child? Explain how you know.

c The driver is very tired. How and why will this affect thestopping distance?

d Name one problem, other than speed, that will affect thebraking distance and say why it will affect it.

e Give one thing, other than speed or tiredness, that will increasea driver’s thinking distance.

Sheet 2 of 3

Speed in kilometres Thinking distance Braking distanceper hour (km/h) in metres (m) in metres (m)

45 (about 30 mph) 9 14

80 (about 50 mph) 16 35

105 (about 70 mph) 21 75

K5


HomeworkSlow down! (continued)

EXTENSION4 Remember the formula for speed. Use this formula to calculate the

speed of the following moving objects. Don’t forget to include theunit of speed in your answer.

a A dog that runs 50 metres in 5 seconds.

b A ship that travels 100 kilometres in 5 hours.

5 Here is a distance-time graph for Sally’s walk to the local shop.

Section D of the graph shows when Sally just reached the shop.

a During which section (A to D) did Sally stop to chat with somefriends?

b How far is it from Sally’s house to the shop?

c Calculate Sally’s average speed during section A of her journey.

Sheet 3 of 3

D

C

B

A

50 100 150 200 250 300 350 400 450 500 550 6000

Time in seconds

0

50

100

150

200

250

300

350

400

450

500

550

Distancein metres

K1


Homeworkmark schemeForces and gravity

Sheet 1 of 5

Question Answer Mark

1 a Underscores show answers; other text copied by pupils.Sally stood on some bathroom scales and measured her mass in kilograms; or Sally stood on some bathroom scales and measured her weight in newtons. 1

b A tennis ball always comes back to Earth because gravity is pulling down on it. 1

c Weight is the force of gravity acting on an object and is measured in newtons. 1

2 Bag of shopping 80 N 1Full suitcase 170 N 1Estate car 1210 kg 1

Total for Help 6

HELP


3 Accept any sentence using the correct scientific meanings of:

a ● weight 1

b ● gravity 1

c ● mass. 1

4 a 86 � 10 � 860 N 1

b 540 � 10 � 54 kg 1

Total for Core 5

CORE


5 a Accept sentences that convey these ideas:Mass is the amount of material in the car and is not affected by gravity, so is constant. 1Weight is the effect of gravity on the car’s mass; lower gravity on the Moon pulls down with less force, so the car has less weight. 1

b Pupils copy the table and insert the missing data:Weight of car on Jupiter � 2250 N 1Mass of car on Venus � 900 kg 1Size of gravity compared to Earth on Mercury � 0.4 1Mass of car in Deep Space � 900 kg 1

Total for Extension 6

EXTENSION

K2


Homeworkmark schemeFriction

Sheet 2 of 5


1 a Underscores show answers; other text copied by pupils.When John rides his bike he stops it by applying the brakes. These press onto 1the front wheel. The force that stops the bike is called friction. 1, 1

b Underscores show answers; other text copied by pupils.On John’s skateboard there are no brakes. The only friction is between the ground and the wheels (or vice versa). 1, 1

2 Pupils copy the table and insert the missing data:Horse … friction B; gravity A 1Rocket… friction A, gravity B 1

Total for Help 7

HELP


3 The temperature gets higher / goes up. 1There is friction between the nose cone and the air, so heat energy is given out. 1Accept equivalent answers.

4 a Tyres or brakes 1

b Wider tyres would increase friction, because a larger surface would be in contact with the road. 1

c The oil reduces friction in the engine by lubricating the moving parts orstopping the metal from rubbing. 1Accept equivalent answers.

d Air would push against the raised boot lid. 1

Total for Core 6

CORE


5 a The pupils graph should show:the points correctly plotted; 1the axes correctly labelled; 1the best fit curve drawn. 1

b The force needed to just move the yacht gets less as the tide comes in. 1Accept equivalent answers.

c The bottom of the boat is curved / has a keel, so as the tide comes in and theboat floats, there is less boat in contact with the sand so there is even less friction. 1* (star)Accept equivalent answers.

Total for Extension 5* (star)

EXTENSION

K3


Homeworkmark schemeBalanced forces

Sheet 3 of 5


1 A, C and DOne mark for each correct answer. 3

2 a Drawing should show an arrow from the dog to Carly, and an arrow of equal length from Carly to the dog.One mark for arrows in opposite directions; one mark for arrows of equal length. 2

b The forces were balanced. 1Accept equivalent answers.

Total for Help 6

HELP


3 a Dead Sea water 1

b The boat floats higher in the water. 1Accept equivalent answers.

c There is more weight so the downwards force is bigger, 1making the boat float lower so it pushes more water aside. 1Accept equivalent answers.

d The boat will float higher in the water / rise. 1

Total for Core 5

CORE


4 a The diagram should show:i ● the weight arrow pointing downwards 1ii ● the friction arrow pointing downwards 1iii ● the upthrust arrow pointing upwards and of a length equal to the other two combined 1

b The upthrust will get smaller. 1

c They will be equal. 1

d The diagram should show the weight arrow pointing downwards, the friction arrow pointing upwards, and arrows of equal length. 1


EXTENSION

K4


Homeworkmark schemeUnbalanced forces

Sheet 4 of 5


1 To make an object begin to move the forces acting on it must be unbalanced. 1To move an object to the right you must push it to the right. 1Once an object is moving at a steady speed the pushing force and the friction force are balanced. 1

2 The diagram should show:a ● both arrows 2 cm long (20 N) 1b ● pushing force arrow 4 cm long (40 N), friction force arrow 3 cm long (30 N) 1c Box B will move (to the right) 1

because the forces are not balanced. 1Accept equivalent answers.

Total for Help 7

HELP


3 a Air resistance / friction 1b Gravity 1c Underscores show answers; other text copied by pupils.

At first, the skydiver speeds up as she falls towards the Earth. This is because force A is smaller than force B. 1Eventually, the skydiver stops accelerating. This happens when force A and force B are equal / the same. 1

d The diagram should show:● an upwards arrow (air resistance and upthrust) 1● a downwards arrow (gravity) 1● both arrows the same length 1

e The same size / length, because the forces are equal / balanced. 1

Total for Core 8

CORE


4 a i 1500 – 55 � 1445 N 1ii 800 – 675 � 125 N 1iii 15 000 – 12 400 � 2600 N 1

b No movement in example iii 1because the lifting force is not large enough to overcome the weight of the container. 1

5 A: The car slows down 1because the friction force / braking force is greater than the force of the engine. 1

B: The crate moves to the left 1because the pushing force to the left is greater than the pushing force to the right. 1

C: The yacht keeps on moving at the same speed 1because the two forces are equal and in opposite directions / balanced. 1

D: The diver slows down 1because the upthrust from the water is greater than the downward force of the diver’s weight. 1

E: The arrow flies to the right 1because the pushing force from the bowstring is greater than the air resistance. 1


EXTENSION

K5


Homeworkmark schemeSlow down!

Sheet 5 of 5


1 a The car’s speed is 340 m/s 1

b The snail is slowest; it moves at 0.01 m/s 1

c The cheetah is twice as fast as the cyclist. 1

2 a John 1

b John runs faster / has a greater speed than James. 1

Total for Help 5

HELP


3 a 9 + 14 = 23 m 1

b The car will hit the child 1because the total stopping distance at 80 km/h (16 + 35 = 51 m) is greater than 45 m. 1

c Tiredness will increase the stopping distance 1because the thinking distance is increased / gets longer. 1

d Any one problem that could affect braking distance, for example:ice on road, water on road, worn tyres, faulty brakes. 1Accept equivalent answers.

e One additional factor that affects thinking distance, for example:The driver drinking alcohol, taking drugs. 1Accept equivalent answers.

Total for Core 7

CORE


4 a 10 m/s (must include unit) 1

b 20 km/h (or kph) (must include unit) 1

5 a Section B 1

b 500 m (must include unit) 1

c 250 � 150 � 1.67 m/s (must include unit) 1Accept 1.6 and 1.7


EXTENSION

Sheet 1 of 1

K


Transition quiz

1 Name the different forces in each of the pictures. Choose fromthe words below.

2 Decide if the box in each of the diagrams would be moving.

Write underneath if it is moving/not moving. If it is moving,show the direction it is going in.

The first one has been done for you.

3 Forces are measured in newtons using a forcemeter. What forcedoes each forcemeter show?

Forces and their effects

................................

................................

................................ ................................

.........................

.........................

Force � .............. N

0 N

10

20

Force � .............. N

0

5

10

15

20

Force � .............. N

0

1

2

3

Force � .............. N

0

0.1

0.2

0.3

0.4

N N N

upthrustair resistance water resistance gravity

........................................

........................................ ........................................

........................................not moving

Sheet 1 of 1

K


Transitionworksheet

1 Forces are pushes or pulls. Forces can make things happen. They can:

A start an object movingB slow down a moving objectC make an object change shape.

Statement A, B or C describes what the force is doing in each picture. Put the correct letter in the box beneath each picture.

2 We show forces acting on objects by using arrows. The arrows show thedirection in which the forces act.

Write the name of the correct force against each arrow. Choose from the listbelow.

3 Look at the pictures opposite. Compare the forces shown on the force meters.

a What do you notice about the size of the force as the block of wood is lowered into the water?

.........................................................................................................

.........................................................................................................

b Can you think why this might happen?

...........................................................................................................................................................

...........................................................................................................................................................


upthrust

air resistance water resistance

gravity weight friction

8

642

8

642

K


Test yourselfForces and their effects

1 a Draw an arrow on the diagram to show the force of friction on the car. Label it friction.

b Draw an arrow to show the weight of the car. Label it weight.

c Draw an arrow to show the driving force of the car. Label it driving force.

d Draw an upwards arrow equal and opposite to the weight. Label it reaction force.

e What would happen if the reaction force was less than the weight?

........................................................................................................................................................................

f Is it possible for the reaction force to be more than the weight? ..............

2 Draw lines to match the descriptions to the diagrams.

3 Write true or false for each statement about mass, weight and gravity.

a Mass is a measure of how much stuff something is made of.

................................

b Gravity is a measure of how much something weighs.

................................

c Gravity and mass are forces, weight is not. ................................

d The weight of something on Earth (in N) � mass (in kg) �10.

................................

Sheet 1 of 3

car goingfaster

car slowingdown

car travellingat steady speed

K


Test yourselfForces and their effects (continued)

4 Complete the sentences by choosing from this list.

a Mark has a mass of 50 kg. His weight is ...................................... .

b His motorbike weighs 5000 N. It has a mass of ...................................... .

c His helmet has a mass of 5 kg. It weighs ...................................... .

5 Write balanced or unbalanced to describe the forces in each of these situations.

a A sprinter as she leaves the starting block ..................................................

b A lorry cruising along the motorway at 60 mph ..................................................

c A car stopping at a traffic light ..................................................

d A duck floating on a pond ..................................................

6 a Label the force arrows on the owl and the pussy cat’s boat with the names of the forces.

b If the owl flew away, how would the forces on the boat change?

..................................................................................................................................................................

c Would the boat be higher or lower in the water without the owl?

..................................................................................................................................................................

d If the boat started to leak, how would the forces change?

..................................................................................................................................................................

e What would happen when the boat was filled with water?

..................................................................................................................................................................

Sheet 2 of 3

...................................... ......................................

500 N50 N 5000 N 50 kg

500 kg 5000 kg

K


Test yourselfForces and their effects (continued)

7 Look at this forcemeter. It measures the weight of different masses.

a What is the weight of the bag hanging on the forcemeter?

................................ N

b What is the mass of the bag hanging on the forcemeter?

................................ kg

c What mass would the bag be if the forcemeter read 25 N?

......................................

8 Fill in the answers to find out the name of the car that went faster than the speed of sound.

1 The unit of force

2 What happens to an elastic material when a weight is hung on to it

3 A force that slows things down

4 A force that makes things float

5 How fast an object moves

6 The force of gravity on your mass

7 How many hours it takes to drive 100 miles at 50 mph

9 Circle the things where very little or no friction is wanted.Underline the things where high friction is needed.

Sheet 3 of 3

0

5

10

15

20

25

30

35 N

1

2

3

4

5

6

7

The name of the car is

......................................

car brake pads ice skates inside of a frying pan

match and matchbox car tyres ski slope

playground slide inside an engine football boots

K


Test yourselfAnswersForces and their effects

1 a Draw an arrow on the diagram to show the force of friction on the car. Label it friction.

b Draw an arrow to show the weight of the car. Label it weight.

c Draw an arrow to show the driving force of the car. Label it driving force.

d Draw an upwards arrow equal and opposite to the weight. Label it reaction force.

e What would happen if the reaction force was less than the weight?

........................................................................................................................................................................

f Is it possible for the reaction force to be more than the weight? ..............

2 Draw lines to match the descriptions to the diagrams.

3 Write true or false for each statement about mass, weight and gravity.

a Mass is a measure of how much stuff something is made of.

................................

b Gravity is a measure of how much something weighs.

................................

c Gravity and mass are forces, weight is not. ................................

d The weight of something on Earth (in N) = mass (in kg) �10.

................................

Sheet 1 of 3

car goingfaster

car slowingdown

car travellingat steady speed

drivingforce

reactionforce

weight

friction

The car would sink.

No

true

true

false

false

K


Test yourselfAnswersForces and their effects (continued)

4 Complete the sentences by choosing from this list.

a Mark has a mass of 50 kg. His weight is ...................................... .

b His motorbike weighs 5000 N. It has a mass of ...................................... .

c His helmet has a mass of 5 kg. It weighs ...................................... .

5 Write balanced or unbalanced to describe the forces in each of these situations.

a A sprinter as she leaves the starting block ..................................................

b A lorry cruising along the motorway at 60 mph ..................................................

c A car stopping at a traffic light ..................................................

d A duck floating on a pond ..................................................

6 a Label the force arrows on the owl and the pussy cat’s boat with the names of the forces.

b If the owl flew away, how would the forces on the boat change?

..................................................................................................................................................................

c Would the boat be higher or lower in the water without the owl?

..................................................................................................................................................................

d If the boat started to leak, how would the forces change?

..................................................................................................................................................................

e What would happen when the boat was filled with water?

..................................................................................................................................................................

Sheet 2 of 3

weightupthrust ............................................................................

500 N50 N 5000 N 50 kg

500 kg 5000 kg

500 N

500 kg

50 N

unbalanced

unbalanced

balanced

balanced

The weight and the upthrust would be smaller.

higher

They would get bigger.

It would sink.

K


Test yourselfAnswersForces and their effects (continued)

7 Look at this forcemeter. It measures the weight of different masses.

a What is the weight of the bag hanging on the forcemeter?

................................ N

b What is the mass of the bag hanging on the forcemeter?

................................ kg

c What mass would the bag be if the forcemeter read 25 N?

......................................

8 Fill in the answers to find out the name of the car that went faster than the speed of sound.

1 The unit of force

2 What happens to an elastic material when a weight is hung on to it

3 A force that slows things down

4 A force that makes things float

5 How fast an object moves

6 The force of gravity on your mass

7 How many hours it takes to drive 100 miles at 50 mph

9 Circle the things where very little or no friction is wanted.Underline the things where high friction is needed.

Sheet 3 of 3

0

5

10

15

20

25

30

35 N

1

2

3

4

5

6

7

N

S T R E T C H E S

F R I C T I O N

U P T H R U S T

S P E E D

W E I G H T

2

E W T O N

The name of the car is

......................................

car brake pads ice skates inside of a frying pan

match and matchbox car tyres ski slope

playground slide inside an engine football boots

10

1

2.5 kg

Thrust 2

K


End of unit testGreenForces and their effects

1 Some pupils are doing an experiment to see which surface has the best grip. They pull a trainer across different surfaces with a forcemeter. When the shoe starts to move, they record the reading of the forcemeter in a results table.

a What is the name of the unit that force is measured in? 1 mark

b Name the force that stops the trainer from sliding. 1 mark

c How will the pupils decide from the results which is the best surface to stop sliding? 1 mark

d Which surface offers the lowest grip? 1 mark

e What do you think would happen to the readings if these materials were spread on the surface:i water? ii sand? 2 marks

2 A container ship is waiting to be loaded.

a Which of diagrams A to C shows what happens when the container is loaded onto the ship? 1 mark

b What will happen if the weight of the container is greater than the upward force on the boat? 1 mark

Sheet 1 of 3

0 1 2 3 4 5 6 7 8 9 10

N

A B C

Surface Force (N)

wood 2

metal 2

plastic floor tiles 3

teflon 1

K


End of unit testGreenForces and their effects (continued)

...continued

The crew lower the anchor into the water.

c What is the name of the downward force of the anchor on the boat? 1 mark

d What happens to this force when the anchor is lowered? 1 mark

e What is the name of the upward force on the boat? 1 mark

f What happens to this force when the anchor is lowered? 1 mark

g Explain your answer to f. 1 mark

3 This bar graph shows how long it takes for different toys to cross from one side of a hall to the other.

a How many seconds did the car take to cross the hall? 1 mark

b Which of the toys is the fastest? 1 mark

c Explain how you chose the fastest toy. 1 mark

d Copy and complete this formula for calculating the speed: 1 mark

The car didn’t go as fast as expected. It was making a squeaking noise.

e How might you be able to make it go faster? 1 mark

Sheet 2 of 3

10

20

30

40

45

5

spider

15

25

35

car beetle fire engine train truck

Toy

Tim

e in

sec

on

ds

0

Average speed = ................................. ...... time

K


End of unit testGreenForces and their effects (continued)

4 a When a car moves, there is friction between the car and the air. What is this force called? 1 mark

b The engine of a car makes it move. What is this force called? 1 mark

5 a What is the b What is theweight of weight of thethe apple? apple now?

1 mark 1 mark

Andrew says that what happens with the apple would be true for all objects lowered into water.

c What type of statement has Andrew made? 1 mark

d What should Andrew do to check his statement? 1 mark

e What should Andrew do to make sure his results are reliable? 1 mark

Sheet 3 of 3

0N

2

4

6

8

10

12

14

16

18

20

0N

2

4

6

8

10

12

14

16

18

20

K


End of unit testRedForces and their effects

1 Some children are playing on a garden slide. They run water down the slide from a hosepipe, and have a plastic sheet at the bottom. They squirt soap on the slide before sliding down.

Apart from the amount of soap, name two other things which might affect how far each child travels along the plastic sheet. 2 marks

2 A container ship is waiting to be loaded.

a Which of diagrams A to C shows what happens when the container is loaded onto the ship? 1 mark

b What will happen to the boat if the weight of the container is greater than the upward force on the boat? 1 mark

The crew lower the anchor into the water.

c What happens to the downward force on the ship when the anchor is lowered? 1 mark

d What happens to the upthrust on the ship when the anchor is lowered? 1 mark

e Explain your answer to d. 1 mark

Sheet 1 of 3

It’s not fair!You didn’t put enoughsoap on for my turn –that’s why you went

further.

That’snot true.

Lots of things affecthow far you go.

A B C

K


End of unit testRedForces and their effects (continued)

3 This parachutist weighs 700 N. After jumping from an aeroplane the parachutist falls faster and faster.

a Which of these statements is true?A The air resistance is greater than 700 N.B The air resistance equals 700 N.C The air resistance is less than 700 N.

1 mark

The parachutist opens the parachute and begins to slow down.

b What happens to the weight of the parachutist? 1 mark

c What happens to the air resistance? 1 mark

This graph shows what happens to the speed of the parachutist after the parachute is opened.

d Explain why the line is horizontal between 25 s and 125 s in terms of the forces on the parachutist. 1 mark

e What happens at time X? 1 mark

The crew on the aeroplane drop a heavy crate of supplies by parachute. It weighs 1500 N and hits the ground so fast the contents are damaged.

f If the crate and parachutist leave the plane together, which will reach the ground first? 1 mark

g How could the parachute on the crate be changed to give more air resistance? 1 mark

Sheet 2 of 3

Spee

d i

n m

/s

Time in seconds

0

10

20

5

25 50 75 100 125

X

15

25

30parachute opened

K


End of unit testRedForces and their effects (continued)

4 a When a car moves, there is friction between the car and the air. What is this force called? 1 mark

b Car A is waiting to move off. Are the forces on it balanced or unbalanced? 1 mark

c How would you describe the movement of car B? 1 mark

d Is car C speeding up or slowing down? 1 mark

e Is car D speeding up or slowing down? 1 mark

f What other effect might an unbalanced force have on the car? 1 mark

5 Look at these diagrams of Andrew’s experiment.

Andrew says that what happens with the apple would be true for all objects lowered into water.

a What type of statement has Andrew made? 1 mark

b What should Andrew do to check his statement? 1 mark

c What should Andrew do to make sure his results are reliable? 1 mark

Andrew compares the weights of different objects in air and in water.

d What pattern would Andrew see in his results? 1 mark

e What explanation could Andrew give for his observations? 1 mark

Sheet 3 of 3

A B

C

D

0N

2

4

6

8

10

12

14

16

18

20

0N

2

4

6

8

10

12

14

16

18

20

K


End of unit testmark schemeForces and their effect

Sheet 1 of 1

Green (NC Tier 2–5)

Scores in the range of: NC Level

4–7 2

8–13 3

14–17 4

18–25 5

Question Answer Mark Level

1 a Newton 1 2

b Friction 1 2

c The one which takes the most force to make the trainer slide 1 4

d Teflon 1 3

e i Readings would all be less. 1 3ii Readings would all be more. 1 3

2 a A 1 3

b The ship will sink. 1 4

c Weight (accept gravity) 1 3

d It gets less/smaller. 1 3

e Upthrust 1 4

f It gets less/smaller. 1 5

g The upthrust (accept force) needed to balance weight of ship is less. 1 5

3 a 23 seconds (allow 22 s–24 s) 1 4

b Beetle 1 4

c The toy that took the shortest time to cover the distance/the lowest bar on the graph 1 4

d Average speed � distance � time 1 4

e Oil/lubrication to reduce friction 1 4

4 a Air resistance 1 4

b Driving force 1 4

5 a 2 N 1 3

b 0 N 1 3

c Prediction 1 4

d Repeat the experiment with a range of other materials that float and sink. 1 4

e Repeat for each material. 1 4

K


End of unit testmark schemeForces and their effect

Sheet 1 of 1

Red (NC Tier 3–6)

Scores in the range of: NC Level

4–8 3

9–14 4

15–18 5

19–25 6

Question Answer Mark Level

1 Weight of child 1 4Size of child/amount of water/swimsuit material 1 4

2 a A 1 3

b The ship will sink. 1 4

c It gets less/smaller. 1 3

d It gets less/smaller. 1 5

e The upthrust (accept force) needed to balance weight of ship is less. 1 5

3 a C 1 4

b Nothing/weight doesn’t change 1 5

c Increases 1 5

d The parachutist is travelling at constant speed because the air resistance is the same as his/her weight/forces on him/her are balanced/air resistance � 700 N. Must mention operation of forces in some form to gain the mark. 1 6

e Parachutist lands 1 5

f Crate lands first 1 4

g Larger canopy/parachute 1 4

4 a Air resistance 1 4

b Balanced 1 4

c Steady speed 1 5

d Slowing down 1 5

e Speeding up 1 5

f Make it change direction/shape 1 6

5 a Prediction 1 4

b Repeat the experiment with a range of other materials that float and sink. 1 4

c Repeat for each material. 1 4

d Objects weigh less in water. 1 5

e Upward force/upthrust of water ‘cancels out’ some of the downward force/weight of the objects. 1 5

Sheet 1 of 1

K


Pupil check listForces and their effects

Learning outcomes I can do I can do I need tothis very this quite do more well well work on this

I can explain the difference between mass and weight.

I can use a forcemeter accurately.

I can name and describe examples of forces.

I can use arrows to show how forces are acting on an object.

I can explain how friction occurs.

I can identify advantages and disadvantages of friction.

I can describe how to reduce the effect of friction.

I can identify balanced forces.

I can explain why things float.

I can describe the relationship between weight on a spring and how far it stretches.

I can identify unbalanced forces.

I can use my ideas of forces to predict the effect of an unbalanced force on a moving or stationary object.

I can explain what speed is and how it is measured.

I can explain how speed and friction affect stopping distance.

I can describe how evidence and ideas are needed to develop theories in science.

Sheet 1 of 2

K


Glossary

Word

air resistance

balanced forces

braking distance

dense

density R

displaces

extension

float

force arrows

friction

gravitational attraction(gravity)

kg

kilograms

kilometres per hour

km/h

lubricant

m/s

mass

matter

metres per second

N

newtons

reaction force

resultant force R

sink R

speed

stopping distance

Definition

Force is measured in newtons.

The short way of writing newtons.

The force of gravitational attraction on an object, thatmakes it feel heavy.

Anything that has mass is made up of matter. Mattercontains particles.

A measure of how much matter an object has.

Mass is measured in kilograms.

The short way of writing kilograms.

The force that is made when things rub together.

A substance that reduces friction by making surfacesrun smoothly against each other.

Arrows we draw that point in the direction of a force.The length shows the size of the force.

Two forces of the same size pulling in oppositedirections.

The amount a spring stretches when you hang aweight on it.

A force that stops things falling through solid objects.When you sit on a chair, your weight is balanced bythe reaction force from the chair.

The force caused by water pushing up against anobject.

An object floats when the upthrust is equal to itsweight. It stays on the top of the water.

An object sinks if its weight is bigger than theupthrust. It moves down in the water. R

Forces pushing in different directions when one force isbigger than the other. An unbalanced force makes theobject move or speed up or slow down.

The size of an unbalanced force, which makes theobject move or speed up or slow down. R


Sheet 2 of 2

K


Glossary

Word

thinking distance

unbalanced forces

upthrust

volume R

weight

Definition

How fast something is moving.

Speed may be measured in metres per second.

The short way of writing metres per second.

Speed may be measured in kilometres per hour.

The short way of writing kilometres per hour.

The distance a car travels after the driver decides tostop but before he or she puts the brakes on.

The distance a car travels after the driver puts thebrakes on but before it stops completely.

The distance a car travels after the driver decides tostop but before it stops completely. Stopping distance= thinking distance + braking distance.

How much space something takes up. R

How heavy a material is for its size. R

The force that pulls everything towards the centre ofthe Earth. The other planets, the Moon and the Sunalso pull things because of gravitational attraction.

Pushes out or replaces.

A dense material has a lot of particles in a smallvolume.

The friction a moving object makes with air.

Forces and their effects (continued)

Sheet 1 of 1

K


Key wordsForces and their effects

air resistance

balanced forces

braking distance

dense

density R

displaces

extension

float

force arrows

friction

gravitational attraction

gravity

kg

kilograms

kilometres per hour

km/h

lubricant

m/s

mass

matter

metres per second

N

newtons

reaction force

resultant force R

sink R

speed

stopping distance

thinking distance

unbalanced forces

upthrust

volume R

weight

K Key words

�



air resistance

balanced forces

braking distance

dense

density R

displaces

extension

float

force arrows

friction

gravitational attraction

gravity

kg

kilograms

kilometres per hour

km/h

lubricant

m/s

mass

matter

metres per second

N

newtons

reaction force

resultant force R

sink R

speed

stopping distance

thinking distance

unbalanced forces

upthrust

volume R

weight

K1 Forces and gravityGreena Newtonsb Towards the centre of the Earth.c She is pulled by gravity towards the Earth.d 450 Ne 100 N1 Weight is the force of gravitational

attraction on an object. We measure weightin newtons. Mass is a measure of how muchmatter an object is made of. Mass is measuredin kilograms.

2 a 700 Nb 550 Nc 880 N

3 Gravitational attraction is the force that pulls an object and the Earth towards eachother.

Reda She is pulled by gravitational attraction towards

the Earth.b Sharon 660 N. Shirley 450 N.c The force of gravitational attraction is less on

the Moon than on the Earth.1 a Weight is the force of gravitational

attraction on an object.b Mass is a measure of how much matter an

object is made of.c Gravitational attraction is the force that

pulls an object and Earth towards eachother.

2 a 700 Nb 550 Nc 880 N

3 a 60 Nb 10 N

4 The more mass an object has, the bigger thegravitational force it has.

K2 FrictionGreena Rough surfaces.b Smooth surfaces.c Our shoes have friction with the pavement,

ships have friction with water, etc.d Put grease/oil on it.1 Friction is made whenever two surfaces rub

together. Where there is friction, heat energy isgiven out. Friction can be reduced by usinglubricants such as oil and grease.

2 Individual answers.3 His invention was a cup that sent oil

automatically to lubricate the engine while itwas moving so that the train didn’t have tostop for it to be done.

Reda Rough surfaces.b Smooth surfaces.c Our shoes have friction with the pavement, etc.d In cold weather the lubricant gets thick and

isn’t so effective as when it’s warm.1 a Friction is useful to help moving things to

stop, like bikes and cars.b By coating the surfaces with a lubricant.

2 Individual answers.3 You can feel the heat/warmth.4 Trains had to stop to oil their engines. His

invention was a cup which sent the oilautomatically to the engine while it wasmoving so that it didn’t have to stop forlubrication.

5 Adequate description of measuring the time ittakes for oils at different temperatures to bepoured via a funnel into measuring cylinders upto a given level.

K3 Balanced forcesGreena If the forces are the same size and pull in

opposite directions, the object will not move.b Arrow downwards labelled ‘my weight’ and

arrow upwards from seat of chair labelled‘reaction force’.

c upthrustd gravity1 When two forces are equal and in opposite

directions, they are called balanced forces. Theforce from the plank when a decorator standson it is called a reaction force. If a man pulls adog with a force of 10 N, and the dog pulls theman with a force of 10 N the forces arebalanced. The forces of gravitationalattraction and upthrust are balanced whena hot-air balloon floats.

2 Appropriate diagram to show balanced forceson dog not moving.

3 The upthrust force of the water on the boat isbalanced by the weight or gravitational force onthe boat into the water.

Reda Ab Cc Weight (or gravitational force) and reaction

force. Appropriate diagram showing arrowalongside person pointing downwards labelled‘my weight’ and arrow pointing upwards fromseat of chair labelled ‘reaction force’.

K Book answersForces and their effects


d Sketches:of book on table, with equal length arrows, onefrom book pointing downwards and a secondfrom the table top pointing upwards;magnet with arrow pointing upwards to it andanother equally sized arrow from paperclippointing downwards;arrows of equal length on each of the puppet’sstrings, one pointing upwards and anotherpointing downwards.

e Appropriate diagram showing boat floating inwater. An arrow alongside the boat is labelled‘weight’ (or ‘gravitational force’) and pointsdownwards. In the water is an arrow of thesame length pointing upwards under the boatand labelled ‘upthrust’.

1 a balancedb unbalancedc balanced

2 Reaction force.3 50 N4 Appropriate diagram showing:

aeroplanewind resistance force of engine

K4 Unbalanced forcesGreena The pull of the rope.b Upwardsc Box A will move to the left and box B will move

upwards.d The mattress will bend.1 When there are unbalanced forces acting on an

object, the object starts to move. It moves inthe direction of the bigger force. When thebigger force is in the same direction as amoving object, the object speeds up. Whenthe bigger force is in the opposite direction to amoving object, the object slows down.

2 a Arrow drawn of 1 cm length.b Arrow drawn of 5 cm length.c Arrow drawn of 10 cm length.d Arrow drawn of 4 cm length.

Reda The pull of the rope.b Upwardsc Frictiond Mattress, plastic foam, plastic ruler, etc.e 950 N1 It might become bent, twisted or even break.2 The moving object speeds up.3 The moving object slows down.4 The foam cushion bends.5 6 N

K5 Slow down!Greena cheetahb About 96 km/hc 15 m1 The speed of an object is usually measured in

metres per second or kilometres per hour. Tofind the speed of an object you must find thedistance the object travels and the time takenfor it to travel that distance.

2 Measure out and mark on the ground a fixeddistance. Use a stopwatch to time all the racersand find who travels that length in the shortesttime.

3 The water on the road causes less frictionbetween the tyre and the road surface.

Reda Danny 5 km/h; Susan 5 m/s; Yin 100 km/h.b 2.5 kmc 10 minutes.d When she was on the bus. The graph is steepest

during that time.1 a For example, ‘Speed like a jet’, etc.

b For example, ‘Fast as a cheetah’, etc.c For example, ‘Slow as a snail’, etc.

2 We add the thinking distance to the brakingdistance.

3 The faster a car is travelling the longer it takesto stop and the further the car has travelled.

4 60 km/h5 Any two of: rain, ice, snow, liquid spill on road,

amount of tread on tyres, etc.

K6 Archimedes’ storyGreena Silverb His body displaced some of the water which

then overflowed onto the floor.c The king thought there would be a difference in

weight if the crown was not all gold.d The relationship between the mass, weight and

volume of an object.1 Silver is lighter than gold. So to make the

crown the same mass, more silver was needed.The crown took up more space and pushed outmore water than the lump of gold becausemore silver was needed to replace the gold hetook out.

2 As he got into the bath, he realised that thevolume of water that he had displaced onto thefloor was the same as the volume of his body.This helped Archimedes to solve the problem offinding out how much space the crown took up.

K Book answers


Reda I would do the same thing that Archimedes did.b His body displaced some of the water which

then overflowed onto the floor.c Yesd No1 The king thought there would be a difference in

weight if the crown was not all gold.2 Probably not. The idea of an object displacing

its own volume of water was essential to hissolution to the problem.

3 The crown had some silver in it. Since silver isless dense than gold, a greater volume of silverhad to be used to replace the stolen gold. Thismade the crown have a larger volume, overall,than a block of pure gold of the same weight.

4 The relationship between the mass, weight andvolume of an object.

5 a He would have measured the volume of alump of gold that had the same weight asthe crown.

b If the volume of the crown was more thanthe volume of the gold then he would haveproved that the crown had some lightermetal in it.

6 As he got into the bath, he realised that thevolume of water that he had displaced onto thefloor was the same as the volume of his body.This helped Archimedes to solve the problem of finding out how much space the crown took up.

K Book answers


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