force, motion and energy year 9 extension science

GZ Science Resources 2014 1

Force, Motion and EnergyYear 9 Extension Science

2GZ Science Resources 2014

The different types of motion

Objects that move from one point of space to another over time are said to have motion. Examples include a tortoise slowly moving across the ground or a bullet moving fast after it has been fired from a gun. Objects that remain at the same point of space over a period of time are called stationary. Examples include a person sitting still on a chair or a parked car.

1a


Speed is a measure of motion

Speed is a measure of the distance travelled over the time taken. The more distance covered by an object during a given time, the faster the speed it is moving.Constant speed occurs when the object travels the same amount of distance at each even time period. When we travel on an object moving at a constant speed we do not feel movement for example travelling in an airplane . Only when we observe other objectsmoving at a different speed to us dowe notice that we are moving.

1a

NOTE: in this unit we also use the symbol V to stand for speed


The relationships between distance, time and speed

Triangles can be used to calculate speed, distance or time.Cover the part of the triangle you wish to calculate and multiply or divide the remaining two values.

The unit for speed depends upon the units for time and distance but the most common unit in the lab is metres per second (ms-1)

1a


1b

Measuring Motion in Science

Quantity Unit Symbol Equipment used

Distance Kilometre km odometer

Metre m Metre ruler

millimetre mm Hand ruler

Time Hour hr clock

minute min watch

second s Stop watch

1b

GZ Science Resources 20146

Converting measurements

Quantities are often measured in different scales depending upon what is most appropriate for the original size. In Science (and Mathematics) we use common prefixes to indicate the scale used. We sometimes want to convert scales from one to another to compare data or to place the measurements into equations.

Prefix ScaleKilo = 1000Centi = 1/100th Milli = 1/1000th

So 1 kilometre = 1000 metres1 metre contains 100 centimetres1 metre contains 1000 millimetres

To convert from metres to kilometres divide by 1000

To convert from kilometres to metres multiply by 1000

1b

Time is measured in “imperial units” 1 hour has 60 minutes and 1 minute has 60 seconds therefore 1 hour has 3600 seconds


Errors may occur in measurements may be reduced by taking the average of a number of readings

When collecting and measuring data in investigations, such as that for calculating speed, errors can occur. This may be due to the measuring instrument and the way it is used. Data can also be recorded incorrectly.Repeating the investigation a number of times and averaging out the measurements can help reduce random errors. This value is called the mean.

The mean is the most common measure of average. To calculate the mean add the numbers together and divide the total by the amount of numbers: Mean = sum of numbers ÷ amount of numbers

Distance walked in 1 minute

Trial 1 Trial 2 Trial 3

Distance (m)

113 121 119

Mean = (113 + 121 + 119 ) ÷ 3 = 117.7 m

1b

GZ Science Resources 2014 8Year 10 Science 2012 8

Acceleration is a change in velocity

Objects that have a change in velocity are said to have acceleration.

An increase in velocity or a decrease in velocity (deceleration) are both types of acceleration. A change in direction while travelling a constant speed is also acceleration. We notice when we are travelling on an object that is accelerating by experiencing a change in gravity or G-force.

1c


Speed and acceleration

acceleration = change of velocity time taken

The units for Acceleration depend on what velocity and time are measured in.

If time is measured in seconds (s) and velocity is measured in metres per second (ms-1) then the units for acceleration with be metres per second per second (ms-

2)

aaverage = Δv Δt

1c

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Factors effecting stopping distance1d

The Stopping distance of a vehicle is the total distance travelled from the time the driver registers they have to stop to the actual stopping point. The reaction time (1.5seconds) is the average time a driver takes to apply the brakes. The main factor affecting the stopping distance is the speed the vehicle is travelling at before the brakes are applied.


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Factors effecting stopping distance1d

Other factors that increase stopping distance include a wet road, low tread on a tyre and worn brakes. These factors decrease friction and therefore the kinetic energy of the car (making it move) is transformed into heat energy at a slower rate.



Speed and Velocity

Velocity measures the speed of an object and the direction it travels. Two objects can have the same speed but different velocities if they are not travelling the same direction. An object can have a constant speed but its velocity can change if it does not travel in a straight line.

This car has a change in velocity because it is traveling around a corner even though it has constant speed.

1e

extension 12


Motion can be represented graphically - Distance vs Time

Distance (y axis) and time (x axis) data can be plotted on a graph to show patterns and compare speeds. The steeper line on the left shows student A has a faster speed than student B.

A straight diagonal line indicates constant speed. A straight horizontal line indicates the object is stationary .

Distance verses Time graph

2a


Motion can be represented graphically – Distance vs Time

A distance time graph can also show acceleration with a curved line (blue) because at each time interval the distance travelled becomes larger and larger. Changes in speed are also shown with a combination of diagonal and horizontal lines (red).


2a



Velocity (speed) can be calculated from a Distance-time graph

2a

Time (seconds)

Dist

ance

(m

etre

s)

A distance - time graph can be used to calculate speed (velocity). The co-ordinates of a straight line in the graph are taken (for example from A to B) by projecting back to the x and y axis.

To calculate the value for time find the difference between t1 and t2 by subtracting the smallest value from the largest value. This will be your time.Repeat to find distance on the y axis. This will be your distance.

Place both values into your formula to calculate speed (velocity) v = d/ t


Velocity verses Time graph

Motion can be represented graphically – Velocity vs Time

A velocity time graph can show acceleration with a diagonal line.Constant velocity is shown with a straight horizontal line.Values can be taken from the graphs and used to calculate acceleration. The blue line shows a velocity of 10ms-1

travelled in 2 seconds.The acceleration would therefore be:

a = ∆v/ t = 10/2a = 5ms-2

2b


Graphs may be used to display motion/time relationships

2b


Distances travelled can be calculated from the area under a velocity-time graph

Velocity verses Time graphvelocity

The total distance can be calculated from a velocity time graph by calculating the area under the graph. Work out the area of each triangle (1/2 height x width) and add to the area of the rectangle (height x width)

For example:d = (½ 8 x 6) + (1/2 8 x 4) + (8 x 12)d = 24 + 16 + 96d = 136seconds

2c

extension


Force can cause an object to change its velocity or to deform.

Forces push, pull, tug, heave, squeeze, stretch, twist or press.Forces change:

The shape of an objectThe movement of an objectThe velocity of an object

Not all forces can be seen but the effects can be measured.

3a


Force is measured in Newtons

Isaac Newton was born in 1642 in England. He created laws of motion and gravity.Isaac Newton used three laws to explain the way objects move and how force acts upon them. They are often called Newton’s Laws.The units of force are named after this scientist and are called Newtons.

3a


First Law

If the forces acting on an object are balanced, then the object will remain stationary or carry on at the same speed in the same direction.

Force one Force twoSTATIONARY

Wind resistance

Road frictionEngine force

Constant speed Gaze

SJ

Balanced forces

Newton’s Laws3a


Second LawIf unbalanced forces act on an object, then the object will accelerate in the direction that the net force acts.

Force one

Force two

Un-Balanced forces

Direction of acceleration

Gaze

SJ

Newtons Laws3a


Third LawWhen a force acts on an object, an equal and opposite reaction force occurs. This is called action-reaction.

Action force

Reaction force

Gaze

SJ

Newtons Laws3a


1b

Units of Force, Motion and Energy in Science

Quantity Unit Symbol Equipment used

Force (weight) Newton N Spring balance

Mass Kilogram kg scales

Motion Kilometres per hour (velocity)

khr-1 odometer

Metres per second (velocity)

ms-1 Ticker timer

Metres per second per second (acceleration)

ms-2 Ticker timer

Energy Joule j

3b


The effects of balanced and unbalanced forces

Gaze

SJ

Support force (reaction force)

Friction force Thrust (resultant force)

Weight force (gravity)

If all four forces acting on an object are equal they are said to be balanced.

3c


In the absence of an unbalanced force an object will either remain at rest or travel with a constant velocity

When sky divers reach terminal velocity they are traveling at a constant speed. The forces of gravity accelerating the skydiver towards earth are matched exactly by the force of friction from the air particles pushing against the skydiver. If the person wears a more aerodynamic suit or points their body downwards so there is less surface area to act against the air which reduces friction then the terminal velocity will be faster.

3c


Unbalanced forces change motion

Balanced forces cause no change in speed or direction, since they exert equal, but opposite, push/pull effects on an object. Unbalanced forces can change the speed and/or direction of an object

Direction of flight

3c


Unbalanced forces change motion

Force two = 120NForce one = 30N

An object experiencing unbalanced force will accelerate in the direction of the largest force. The net force can be calculated by subtracting the smaller force from the larger force.

Net force = 120N – 30N = 90N pushing the object from right to left

Net force

3d

GZ Science Resources 2014 29 Gaze

SJ

Close-up

Friction often provides opposing force acting on moving bodies

Friction occurs when one surface moves against another. Friction always opposes force.When friction occurs, kinetic energy from movement is changed into heat energy.Smooth surfaces create less friction than rough surfaces. Friction that occurs between air or water and a solid body is called resistance.

3e


Sometimes friction is useful, at other times it is unhelpful.

situation Increased by

walking Having grip on the soles of your shoes

cycling Wider tyres with tread

driving Good tread on tyres. Brake pads

Situations where Friction is useful

situation decreased by

Friction in bearings

Oil around bearings

Drag on car Aerodynamic design to reduce drag

Drag on snowboard

Smooth laquered surface

Situations where Friction is unhelpful

3e


The relationship between force, mass and acceleration given by the equation F = ma

The Force experienced by an object can be calculated by multiplying the mass of the object by its acceleration.

Force = Mass x Acceleration

If more force is applied to an object then it will accelerate faster

3f

extension


Acceleration of a body depends both on its mass and on the size of the unbalanced force acting on it

Force = Mass x Acceleration

If the same amount of force is applied to two similar objects that have different mass then then smaller object will accelerate faster.

3f

extension


All objects have Mass. Mass refers to the amount of atoms in an object.The formula symbol for mass is m.Mass is measured in grams (g) or kilograms (kg). 1kg = 1000gThe mass of the object remains the same regardless of its location.

Mass and weight

The weight of an object depends on its location and the gravity pulling down on it.The weight of an object can change depending on where it is located. Astronauts weigh less on the moon because the force of gravity is less, but their mass is the same in both locations.

4a


Mass and weight4a


Gravity is a force which acts between bodies even though they are not in contact

Objects create a gravitational field around them

>the bigger the object; the stronger the field

>the further away from the object, the less gravitational pull

Any other object within the field is pulled to the center of the mass:

>accelerating

>feeling weight

Weakest pull

Strong pull

Not so strong pull

acceleration

Gaze

SJ

4b


The Earth is the source of a gravitational field

Isaac Newton was also famous for his work on gravity. His law of universal gravitation states that objects with mass attract each other with a force that varies directly as the product of their masses and decreases as the distance between them increases. This gravitation force causes objects to accelerate towards the centre of the Earth (remember F = m x a). Once they reach solid ground the support force prevents them falling any further. Because we also have mass the Earth feels a gravitational attraction and accelerates towards us but our mass is so tiny compared to the Earth and the effect is not noticed.

4c

extension


The mass of the Earth creates an acceleration of 9.82 ms-2 for objects falling towards it. Regardless of the size of the object, they all fall with the same acceleration - only the shape, which causes changes in air resistance, causes some objects to experience more opposing force and accelerate slower.

To calculate our weight, which is a force on an object in a gravitational field, we multiply our mass by the gravitational acceleration of Earth (9.82ms-2)

The Earth is the source of a gravitational field

Force = mass x acceleration

Weight = mass x gravity

4c

extension


The links between forces and energy

When a force is applied to an object of mass and moves it over a distance then work has been done.Work is measured in joules.To do 1 joule of work you need 1 joule of energy.

Work = force x distanceW= f x d

extension

5a


The links between forces and energy

Power is a measure of work done over time. Power is measured in units called watts. Power = work/time

P = w/t

Force = 20N

Distance = 5 metres

Time = 25seconds

A car is pushed with a force of 20N and travels 5 metres. The work done is w = f x d w = 20 x 5 = 100 joulesThe power used to push the car is p = w/t p = 100/25 = 4 watts

5b

extension


Kinetic energy

An object has kinetic energy when it is moving. Kinetic energy that an object contains depends upon both its mass and the velocity that it is moving.An object with more mass will possess greater kinetic energy than an object with less mass that is traveling at the same velocity.

Kinetic energy = 0.5 x mass x velocity2

KE = (0.5) x (m) x (v)2

extension

5c


Kinetic energy

Kinetic energy = 0.5 x mass x velocity2

KE = (0.5) x (m) x (v)2

An object that has the same mass as another but is travelling at a greater velocity will contain far more kinetic energy.This can be demonstrated by two similar vehicles hitting a stationary object. A vehicle travelling at 100km per hour will release a much greater amount of kinetic energy on impact compared to a vehicle only travelling at 50km per hour.

5c

extension


Energy makes things happen

Energy is not a substance or an object that you can touch or hold, but substances and objects can possess energyEnergy is something that is required to make things changeEnergy is needed to make objects move or change their state

6a


Energy makes things happen

Any change in speed, size, shape or temperature in an object requires energy. Energy is the ability to do work.Work is applying force to an object and making it move in distance.

6a


Energy is measured in a unit called a joule (J).

A Joule, unit of work or energy, is equal to the work done by a force of one Newton acting through one metre. This unit is named in honour of the English physicist James Prescott Joule.W (work) = F (force) x d (distance)

6a

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Power is a measure of energy use. Power is how quickly energy is being used which is called the rate ofenergy use. Power is the amount of energy used in a period of time and the units are called watts.1 joule of energy for 1 second = 1 watt of power1 watt of power for 1 second = 1 joule of energy

Power is measured in a unit called a watt (w).6a


Energy can exist as Chemical potential, Gravitational potential, Elastic potential, Kinetic, Sound, Electrical,

Light, Heat

Energy can be classified into two types; kinetic energy (KE) and potential energy (PE)Kinetic energy is seen when particles, waves or objects moveAll forms of stored energy are called potential energy – this can not be seen until it is transformed (changed) into active energy

6b

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Light (radiant)Energy

Energy traveling in waves, with wavelengths that can be seen by humans.

SoundEnergy

Sound travels in waves of different pressure. This causes movement of particles. Sound cannot travel in a vacuum.

Mechanical kinetic Energy

Movement energy. This can be seen when matter changes its position in space

Heat (thermal)

EnergyThe kinetic energy that atoms contain. The more they move the more heat they contain. Measured by temperature

ElectricalEnergy

Energy contained in electrons. This can either be static like lightning or current electricity that moves in a circuit.

Kinetic energy is seen when particles, waves or objects move


6b

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GravitationalEnergy

This is the energy contained by an object which pulls it back to Earth. The further up from the ground the more it contains.

Elastic Energy

Found in springs, rubber bands etc. The more they are compressed the more energy they contain to make them change back to their original shape

NuclearEnergy

The energy contained by the nucleus of an atom which holds the neutrons and protons together. A lot of energy is released when these are separated in a nuclear reaction

ChemicalEnergy

The energy contained in the bonds of chemical molecules – i.e.food or battery acid. When these bonds are broken in a chemical reaction then their energy is released

GeothermalEnergy

Energy produced by geological processes of the Earth which causes heat and pressure to rise to the surface.

MagneticEnergy

Energy contained by a magnet to either attract or repel other magnetic objects. It can also cause electrical currents.

All forms of stored energy are called potential energy


6b


Energy is always conserved.

Energy can not be created or destroyed, it can only be changed from one form to another.

The total amount of energy never changes. Energy is able to transform from one type to another. All types of potential energy must be transformed into kinetic energy in order for work to be done.

7a


Energy can be transformed from one type to another

Energy can be transferred from one object to another. e.g. heat energy from the rocks cooking the food in a hangi. The type of energy does not change

Energy can be transformed from one type into another. e.g. electrical energy changed into heat and sound energy when boiling a jug.

One type of energy can be transformed into many different types.

7b



Any object lifted upwards gains in gravitational potential energy. This gravitational energy transforms back into kinetic energy when it is released or no longer supported. Hydroelectric power stations use the gravitation potential energy of water to flow downwards through a spillway and move turbines.

All bonds that hold atoms, ions and molecules together contain chemical potential energy. When these bonds are broken or the atoms form molecules of lower energy then heat energy is released. Respiration in our cells involves releasing energy that is contained within the bonds of glucose molecules.

7b

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Batteries contain energy in the form of chemical potential energy. When a complete circuit is connected to the terminals then chemical reactions take place and the potential energy is transformed into electrical energy.

Sunlight produces radiant energy in the form of thermal heat and light energy. Only light energy is used by plants and it is transformed into chemical potential energy through the process of photosynthesis. Chloroplasts in the leaves contain a chemical called chlorophyll that captures the light.

7b

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Renewable and Non-Renewable Energy

Energy types can also be divided into renewable and non renewable energy. Renewable energy sources can be used continuously with out running out. Renewable energy is available in unlimited amounts and technology has developed so we can convert it into electricity, heat and fuel for human use.Non-renewable energy resources have often taken many millions of years to form and they are in limited supplies. Once they have been used up they can not be replaced.

8a

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Renewable Energy

Energy is generated by the sun, and is stored in a variety of forms. It is locked into biomass through the process of photosynthesis. Burning biomass releases energy, as does decomposing biomass. Energy is stored in the oceans and fresh water where the movement of the earth and gravity release it through tides and flowing rivers. The earth’s spin generate waves and wind. Heat created from the center of the Earth is released through geothermal activity. All of these energy sources can be used by humans.


8a


Non-Renewable Energy

Non renewable energy is energy that comes from the ground and is able to be not replaced within a useful period of time. Fossil fuels are the main category of non renewable energy. Fossil fuels include; coal, oil and natural gas. These resources come from animals and plants that have died millions of years ago and then decomposed to create a useable source of energy for humans. Mined minerals such as uranium used for nuclear power are also non renewable sources of energy.

8a

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Fossil Fuels - Coal

Coal was formed millions of years ago when plants fell into peat swamps and were buried by heavy earth and rocks. Over millions of years, the weight of the rocks and heat in the ground turned the plants into coal.Most of the world’s coal was formed 300–350 million years ago during the Carboniferous period that was warm and damp, ideal for plant growth. New Zealand coals are much younger – they were made 30–70 million years ago and they are a less energy rich fuel. Coal is mined either underground or in large open cast mines.

8a

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Fossil Fuels – Oil and Gas

Oil and gas were formedmany millions of years ago fromdead sea organisms falling to the sea floorand being covered by sediment. Over time thesediment that covered these dead creatures was compressed and formed rock. The carbon and hydrogen atoms that used to be part of the dead organisms bodies reformed into fuel – the liquid form called oil and the gas form. Oil and gas are mined by drilling deep into the ground from oil rigs.

8a

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The limits of fossil fuels and the unlimited energy of the sun

Fossil fuels

Renewable energy


Fossil fuels are a limited resource. Extraction and mining can be expensive and can damage the surrounding area. Carbon dioxide gas that is released upon burning the fuels are contributing to the warming of the climate. Human society has a dependence on fossil fuels for energy but needs to consider alternative renewable energy sources to replace decreasing coal, gas and oil supply. Renewable energy is sustainable and in many cases produces little or no harm to the environment. As new technology develops to collect the energy it will become cheaper.

8b

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Hydroelectric power makes electricity by using the energy from falling water. The water comes from big dams across rivers, and flows down great tubes to drive electricity generators. New Zealand is fortunate to have many rivers, such as the Waikato river, which are suitable to make use of this type of energy source.

Hydroelectric energy8c


Wind power can drive a turbine with a propeller and generate electricity. Wind power is becoming more popular in New Zealand and a number of “farms” have been created such as along the hills in Manawatu and the new site between Hamilton and Raglan.

Wind energy8c


Solar power can make electricity by using panels called photovoltaic cells which converts sunlight into direct current electricity. An inverter changes the direct current into alternating current which can then be used by households and industry to power machines and appliances.

Solar energy8c

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Biomass energy

Biomass relies on the photosynthetic ability of plants to convert solar energy into chemical energy. The chemical energy stored in plants is then broken down by enzymes and useful bacteria into biofuels to be used in machinery. This type of fuel is renewable as long as the same amount of trees are planted to replace those cut down. The carbon dioxide released when burning the fuels will also be reabsorbed by the plants as they grow.

8c


Geothermal energy

Geothermal energy can be used to heat water pumped underground into hock rocks and the steam created then powers turbines to create electricity. Hot steam that comes from naturally occurring vents can also be used.

8c


Energy efficiency – how sources of energy are transformed into useful energy and wasted energy

When energy is transferred, some of the energy turns into forms we don't want.This energy is called wasted energy.

Wasted energy takes the form of heat and sometimes sound or light.During any energy transfer, some energy is changed into heat.The heat becomes spread out into the environment.This dispersed energy becomes increasingly difficult to use in future energy transfers.

In the end, all energy is transferred into heat and eventually lost out into space.

9a


Efficiency is a measure of how well an energy user (i.e, bulb or appliance) transfers energy into the form we want.

efficiency (%) = (useful energy out ÷ total energy in) x 100.orefficiency (%) = (useful power out ÷ total power in) x 100

Energy efficiency – how sources of energy are transformed into useful energy and wasted energy9a


Energy efficiency – comparing types of light bulbs

Incandescent Compact Florescent LED

Life Span (average) 1,200 hours

8,000 hours 50,000 hours

Watts of electricity used (equivalent to 60

watt bulb). 60 watts 13-15 watts 6 - 8 watts

Each of these types of bulbs produces the same amount of useful energy but require different amounts of input energy

9b


Transformation losses and inefficient use increase the amount of energy required

A large amount of energy use in a home is spent on heating. If a home is poorly insulated (with materials that do not conduct heat) then the heat will easily escape and more energy will be required to maintain the temperature to a suitable level. Leaving lights on when not being used, using standard incandescent light bulbs instead of the CFL or LED bulbs and leaving appliances switched on at the wall when not in use are all inefficient uses of energy.

9d


It is important to reduce the loss of heat from our homes. This is done by increasing the insulation of our homes using the methods shown in the diagram below.

Reducing energy loss from our homes9d


9d


Becoming more energy efficient

Light bulbs

Televisions

Refrigerators

OLD NEW

Appliances for use around the house are being designed to be more energy efficient. This means that they require less input energy to produce the same amount of useful energy output. Less waste energy is produced in the form of heat and sound.

9d


Energy can be transferred by conduction, convection or radiation

Methods

of heat

transfer

Conductionof heat alonga solid object

Convection currents in liquids or

gases

Radiation of heat

waves from hot objects

10a


Liquids and Gases transfer heat energy by Convection

Convection occurs when free moving particles found in liquids and gases have heat energy added to them. This causes an increase in kinetic energy of the particles and as they collide into each other they push apart more. The hotter area of liquid or gas becomes less dense or lighter and rises. As the particles lose energy they slow down and become closer to each other which makes them denser and they fall back down. This movement creates convection currents where the particles circulate.

10a


When you heat the air in the balloon your increase the kinetic energy of the air particles. The air particles absorb the heat energy and move faster. This makes them move faster. Air particles are pushed out of the balloon, as they take up more space.A hot air balloon rises because it is filled with hot, less dense air and is surrounded by colder, more dense air.

Hot air balloons rise due to Convection

10a


Solids transfer heat energy by Conduction

When heat is transferred by conduction – the atoms remain in fixed solid position – and the heat energy is transferred from one atom to another by being carried by moving electrons surrounding the atoms. The more heat energy an electron has the faster it moves.Some materials conduct better than others. They are called conductors and include metals which have electrons that are free to move. Those materials that cannot conduct heat are known as insulators. They have no free electrons to carry the heat energy.

10a


white

silver

black

absorbed

reflected

Temp. down

Temp. same

Temp. up

Radiation source

Vacuums transfer heat energy by Radiation

Heat Energy can transferred in waves – it does not need atoms or electrons to travel. Our greatest source of radiation waves comes from the sun.White and silver objects reflect radiation and very little heat energy is transferred to them. Black objects absorb radiation and a large proportion of the heat energy is transferred to them.

10b


The method of heat transfer is linked to the state of matter

HeatTransfer type

What does it travel in?

Does it require matter to travel?

Description example

convection LiquidAndgas

yes Heat energy contained by particles that move and carry it.

Hot air balloon rising when burner is going

conduction solids yes Heat energy is passed from particle to particle.

A metal spoon heating up in a hot drink

Radiation In a vacuum

no Heat energy travelling in infra-red waves at the speed of light

Skin warming up while sitting in the sun


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The method of heat transfer is linked to the state of matter

Convection requires particles to move around such as in liquid and gas and carry around the heat energy like a rugby player carrying the ball and running.

Conduction passes the heat energy from particle to particle and occurs in solids when the particles are fixed in place. This is like the rugby players passing the ball from one to another.

Radiation does not require particles to move the heat energy. This is like a rugby ball kicked which then moves by itself down the field without any players required.


LawEnergy can not be

created or destroyed it can only change

from one form into another

transformations

light

soundnuclearelectrical chemical

kineticpotential

Activeheat

geothermalelastic

gravitational magnetic

energy

Heattransfer

radiationconduction convection

No matter solidsLiquids

Andgases

Waveselectromagnetic Energy

moves

Particlesmove

expansion contraction

Hotter colder

particles

Black

Whitesilver

absorb

reflect

conducters

Non-conductersmetals

Plastics

insulators

Air(non solids)

MoreSurface

AreaMoreHeatloss

Energy efficiency=Useful energy x 100

Energy used

force, motion and energy year 9 extension science

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