Chapter 5: Heat and Heat Transfer

But who cares?- Your body must stay close to 37.0 degrees Celsius. If your

body gets too hot, your internal organs may be harmed or you will get sick. If your body is too cold, you risk hypothermia. Is this why Canadians have more kinds of clothes than anyone else in the world?

Name: __________________________________________

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Unit 3: Energy Transfer Technologies

What you will learn:- Where heat comes from

- How heat transfers from one

object to another

- The way climate is controlled

by heat transfer

- Methods of heat transfer used

by various technologies

Date: ___________________________________________

I want to see what you know about hot and cold temperatures. You can use your cell phones to help you with this task. MATCH the correct temperature to the appropriate description found on the right. Have fun!

1. -273 C ____ Boiling temperature of water (at sea level)

2. -218 C ____ Body temperature of a healthy human

3. -138 C ____ Hot chocolate or coffee

4. -89 C ____ Comfortable room temperature

5. -5 C ____ Soft ice cream

6. 0 C ____ Coldest temperature possible

7. 1 C ____ Melting point of aluminum

8. 7 C ____ Temperature of oven to bake cookies

9. 20 C ____ World record coldest air temperature

10. 37 C ____ World record hottest air temperature

11. 40 C ____ Air in a refrigerator

12. 58 C ____ Surface of the sun

13. 80 C ____ Lava from Hawaiian volcanoes

14. 92 C ____ Melting point of oxygen

15. 100 C ____ Ocean currents off Canada’s East coast

16. 180 C ____ Body temperature of a budgie bird

17. 357 C ____ Where the Space Shuttle flies in orbit

18. 660 C ____ Boiling point of mercury

19. 1150 C ____ Comfortable for heat-loving bacteria

20. 5550 C ____ A slush of pure water and ice

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Boiling Hot or Freezing Cold?

I want you to rub your hands together really fast press as hard as you can. What is happening? Why is this happening?________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Robert Brown was the first to _____________________________ ____________________________. He discovered that when particles got hotter, they moved ____________ and when they cooled, they moved more _______________.

Kinetic energy is _______________________________________________________________________________________________________________________________________________________________________.

Temperature is ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Heat (or thermal energy) is ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Examples:3

Friction

Random Movement

o Imagine you have a spoonful of water at 25oC and a spoonful of water at 45oC. Which has more heat or thermal energy? Why?

__________________________________________________________________________________________

o You have a cup of water at 25oC and a bucket of water at 25oC. Which has more heat or thermal energy? Why?

__________________________________________________________________________________________

o There is a huge iceberg at -10oC and a small pot of boiling water (100oC). Which has more heat or thermal energy? Why?

__________________________________________________________________________________________

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45oC

25oC 25oC

Conduction,

Radiati

Remember, heat transfers from where there is ________________ to where there is __________________.

CONDUCTION Occurs only in _______________ The particles __________________________________________ ____________________ and

begin to ______________________ _____________. This makes them _________________________ __________________, giving _______________ to these particles, making them _______________________.

CONVECTION Occurs only in _________________________. Particles must be _______________________________________ ________________ with one

another. When the particles ______________ the heat source _________________________, they

____________________ from one another and become ______________________. These __________________________. As they rise, __________ ________________________.

These particles eventually become hot and rise too. As the particles get to the top, they begin to __________________________.

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Conduction,

Radiati

RADIATION Unlike conduction and convection, radiation can _________________ _______________

(where there are __________________ at all). Heat travels in ___________ called _______________________. Radiation moves in waves ________________________________. Think about a stove…

you can stand _____________________ and feel the ____________________. Energy also travels in waves from the ________________________.

Does being near a large body of water, such as an

ocean or large lake, affect climate?

Look at the chart on page 96 of climate patterns of Calgary, Quebec, Regina, Vancouver and Winnipeg

and answer the analysis questions.

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How Ocean

s Affect Clima

te

Topic 5.5 –Heat Transfer and Technologies

Begin on page 98 of your textbook to help you find the answers to the following questions. You will have to read the “Did You Know” boxes and the captions under the pictures to help you find all of the answers.

1) Explain why many metal cooking pots have hard plastic or wooden handles. Be sure to use the word CONDUCTION in your answer!____________________________________________________________________________________________________________________________________

2) Using the words conduction and convection, explain how a pot of soup on the stove will heat up. Begin with how the heat transfers from the burner to the pot. You may use a labeled diagram if you wish.____________________________________________________________________________________________________________________________________

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3) Some cooking pots do have a metal handle. You must wear an oven mitt in order to lift the pot off of the stove. How does an oven mitt prevent you from being burnt? Do you think it is preventing conduction, convection or radiation of heat from the handle to your hand?____________________________________________________________________________________________________________________________________

4) Describe all the different methods of heat transfer occurring in an oven to bake a cake. Be sure to include conduction, convection and radiation in your answer. You may write it out or use a labeled diagram.______________________________________________________________________________________________________________________________________________________________________________________________________

5) Why do people in hot countries tend to wear mostly white or light coloured clothing?________________________________________________________________________________________________________

6) Engines create a great deal of heat when they are running. This heat must be removed so that the engine does not overheat and get damaged. The process to cool an engine is

a. The engine’s cooling system contains a __________________. Heat is ______________ from the engine to the ________________.

b. The coolant is pumped through the engine block to the _________________. A radiator is a honeycomb made of a metal alloy (two different metals combined). The metal alloy is a good ___________________. Heat from the coolant is _______________ through this alloy to the ________.

c. Either a fan or the motion of the vehicle forces this _______ through the radiator. __________ is transferred to the air that rushes through the radiator.

7) An air cooled engine (like that in Fig. 5.19) has no radiator to cool it. How do you suppose it keeps from overheating?____________________________________________________________________________________________________________________________________

8) One hot July day you and your friends go to the beach. You decide you are way to warm, so you go for a swim. When you come back out of the water, despite the fact that it is really hot, you feel quite cold as you begin to dry under the sun. Why do you feel cold until you are dry? Hint – read page 101.

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_____________________________________________________________________________________________________________________________________________________________________________________________________

9) CHALLENGE QUESTION!!Suppose you are given two cups of hot chocolate. One cup is made of shiny metal, and the other cup is made of a metal that has been painted black. Which cup do you think will keep your hot chocolate warm longer? Why did you chose that one?______________________________________________________________________________________________________________________________________________________________________________________________________

Chapter 6: Controlling Heat Transfer

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Chapter 6 – Controlling Heat TransferFire Walkers

Fire walkers have learned to reduce the transfer of thermal energy from the coals to their feet. How can they do this?

_______________________________________________________________________________________

_______________________________________________________________________________________

6.1 Absorbing and Losing Heat Different materials absorb heat at different rates – this is called

______________________________________.

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What you will learn:

- How buildings keep heat in

- How firefighters are protected

from extreme temperatures

- How heat loss is measured

- How different materials

absorb heat at different rates

Some objects or substances are better at absorbing heat than others. Sometimes we can speed up the process of heat absorption.

Specific Heat Capacity

Is a measure of how well a substance can absorb ________________.

If a substance is __________ at absorbing heat it will take a very long time to heat up.

In the case of our ice cubes, we had to heat them up in order to melt them. Is water good at absorbing heat?

Can you think of any substances that take a long time to heat up? What about a short time?

_____________________________________________________________________________________

_____________________________________________________________________________________

Specific Heat Capacity

Specific heat capacity is measured in Joules per gram degrees Celsius. The specific heat capacity of water is ___________ J/g x ºC

This means it takes 4.19 Joules of energy to raise the ___________________ of water by 1 degree Celsius.

Specific Heat Capacity of sand is 0.66J/g x ºC

Compare this to water – which one will heat up faster? Why?

______________________________________________________________________________________

______________________________________________________________________________________11

6.2 Keeping Heat at Home Remember – Heat moves from __________ to __________!

If we heat our houses, the heat will try and move from ______________ to __________________ (where it’s cold!)

How can we keep heat inside our homes?

INSULATION!

Proper insulation ________________ heat transfer.

What about in the summer? How can insulation help us?

Insulation not only keeps ______________________ in but it keeps ___________________ out! Hot air will try and move ___________ your house on a hot day – insulation prevents it from doing so!

R value

R value is a ______________ of how well an insulating material slows heat transfer. Materials with ___________ r-values are better insulators than those with

______________ r-values. An insulation of R-12 loses heat faster than one with R-16. When insulators are used together, the total R-value is all of the R-values added

together.

Examples:

Insulating Material R Value25mm Air space in a wall cavity 2.0425mm Air space with reflective surface in wall cavity 5.5425mm Expanded polystyrene 3.9625mm Rigid urethane foam 7.5025mm Fibreglass 4.2525mm Solid wood 1.2525mm Wood shavings 2.4225mm Clay brick 0.1125mm Concrete 0.1925mm Glass 1.0025mm Thermal glass 1.8

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Look at the table of R-values above and answer the following questions.Calculate the R-values of the following:

• Insulating with wood shavings and concrete

• Insulating with thermal glass and fiberglass

• Insulating with solid wood and rigid urethane foam

• 50mm solid wood

• Which one is most effective?

Other Ways to Keep Heat in the House

1. Windows and Doors that keep heat inAs you saw from the table, glass is not the greatest insulator – heat will escape

______________________ through glass and if you have lots of windows in your house this means lots of _______________ lost!

Today we use ____________________________________ – this provides a space of still air which keeps heat better than regular glass.

We make doors with __________________ that can be filled with insulation in order to trap heat.

Controlling Heat Transfer

How else can we keep heat from escaping?Think of your pizza delivery man – how is pizza delivered to your house?

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_____________________________________________________________________________________

What about in the kitchen? How do we keep from burning ourselves on hot objects?

____________________________________________________________________________________

Thermos

A thermos blocks each of the three methods of heat transfer in order to keep drinks hot all day!

Inside is a __________________ glass jar – one jar inside the other (similar to double pane windows)

Some air is removed between the two jars – this space is a ______________________________________

Jars are painted with a silver ______________________ coating.

Rubber or plastic keeps glass away from _______________________.

Cap is ____________________.

6.3 Keeping Yourself Warm

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How can we keep ourselves warm on cold days? Everyone (other than Casey) must dress for the weather.

Good ideas: wear several _____________ – air that gets trapped in material serves as insulation.Wear a ________________________ outer

layer – this keeps warm air from escaping!

DownMany warm winter clothes, comforters and

jackets contain _______________. Down are the fluffy feathers that are found

________________ the feathers that you see – when down is fluffed, it holds air in place.

In a jacket, this keeps air from blowing through the down and ________________________ cold air for warm air.

Keeping Yourself Warm

Remember: a _____________ body is a _________________ body!

When you work hard, you sweat – when _______________ leaves your body, it cools you down.

When you’re _____________________, you want to keep yourself dry so you don’t lose body heat – if you start to sweat, __________________ layers until you stop moving.

People of the North

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Traditional Inuit clothing is made from ____________ hides – an inner layer is worn with fur next to the skin, which ________________ body moisture through the fur and leather skin.

The outer layer is worn with the fur on the ________________ – the hood traps air in front of the face – cold air is _______________ up before it’s breathed in, which protects the lungs.

When it’s very cold, water ______________ from the lungs can freeze on people’s faces and clothes.

Inuit hoods are designed to prevent this – fur on the hood is made from ____________________, wolf or dog fur. __________ won’t stick to these kinds of furs!

____________ layers are worn on the feet in winter – seal skin is preferred because it’s __________________________.

Dressing for Intense Heat

Firefighters go into blazing infernos dressed in many layers – why?

_______________________________________________________________________________________

Their suits are made of a special material, which contain ______________________________ chemicals. This means the fabric will ____________ but it will not burn – this charred material produces a layer of ___________________________ that protects the firefighter from too much heat.

Material on the inside of their fire suit ______________________ body moisture and helps

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keep the firefighter cool.

Dressing for intense cold

Even in hot climates, deep water can have very _________ temperatures.

Scuba divers wear tight suits that prevent cold water from causing cooling by _____________________________.

If cold ocean water moved in and out of the suit, a diver would be very cold. Water would

pick up ____________ from the skin and carry it into the ____________________.

Diver suits have _________ trapped in the fabric, which provides lots of ________________________.

Test Your Understanding Page 126-127

#2a) _______________________________________________________________________________

#2b) _______________________________________________________________________________

#3. ______________________________________________________________________________________

____________________________________________________________________________________________________________________________________________________________________________________

#5. ______________________________________________________________________________________

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____________________________________________________________________________________________________________________________________________________________________________________

#7. ______________________________________________________________________________________

____________________________________________________________________________________________________________________________________________________________________________________

#8. ______________________________________________________________________________________

____________________________________________________________________________________________________________________________________________________________________________________

#11. _____________________________________________________________________________________

____________________________________________________________________________________________________________________________________________________________________________________

Chapter 7 – Simple Machines and Energy Transfer

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Keeping things in balance:In this activity you will investigate factors that balance or bring a teeter-totter into equilibrium.

What you will need:19

What you will learn….

- How work and energy are related

- How simple machines operate

- Why it is necessary to develop

more energy-efficient machines

- How to analyze the output of

simple machines.

But who cares?......- Both your personal budget and the global environment demand

that machines be energy efficient. As you shift from non-renewable to renewable energy sources, you protect both. When you understand how simple machines work, you will have the wisdom of the ancients to hel you make energy-efficient decisions.

Metre Stick

Retort stand and clamp

Box of hanging masses

String

What to do:

1. Tie a metre stick so that it hangs, balanced, from a clamp on a retort stand. See the illustration of page 129.

2. Attach a 50 g mass 40 cm from the balance point of the stick

3. Hang a 50 g counterweight at the other end of the stick. Move the 50 g mass until the stick is in balance.

4. Record the distance from the center of the metre stick to the position where the 50 g mass balances the meter stick

5. Remove the hanging counterweight. Repeat steps 3 and 4 using a 100 g mass, a 200 g mass and a 500 g mass. Record your observations.

Type of Weight Distance from center (fulcrum)50 g

100 g

200 g

500 g

All kinds of energy

1. A bungee jumper has _________________________________

2. A moving baseball has ______________________________

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3. A light bulb has __________________________________

4. An outlet has _____________________________________

5. A stove element has __________________________________

6. A speaker has _______________________________________

Work, work, work…

Write down what you think “work” means…what does it include? How do you know if you are working?

__________________________________________________________________________________________

__________________________________________________________________________________________

In science, work happens when __________________________________

_____________________________________________.

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In order for work to have occurred, you must exert some ____________ (force) and the object must

_____________.

Is work done in the following situations? Why or why not?

A person walks up the stairs._______________________________

____________________________________________________

A bike rider coasts down a hill. _____________________________

____________________________________________________

The amount of work that is done can be calculated using a simple formula:

Work = Force x Distance

Example:

a. A person uses 5N of effort to lift an object 2m. How much work was done?

b. A person pushes against a wall using 50N of force. They want to move the wall 1m, but it does not

even budge. How much work was done?

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Work worksheet

Review of Terms:

1) Scientifically, work means that a _______________ has been applied and caused an object to

_______________. Work is measured in __________ (__).

2) Force means ________________________________ and is measured in _________________ (__).

3) Distance is measured in __________ (__).

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Calculations

4) A student is rearranging her bedroom. She decides to move her desk across the room. She exerts 200 N of force and moves the desk a total distance of 3.0 m. Calculate the amount of work done.

5) In one investigation, a student pulled a heavy block a total of 4.5 m along a wooden floor. She exerted 3.5 N of force to move the block. Calculate the amount of work done.

6) In a second investigation, a student pulled the same heavy block a total of 4.5 m over a carpeted floor. This time, it required 6.0 N of force to pull the block. Calculate the amount of work done.

Why did it take more effort to pull the same block across the carpet as compared to the wooden floor?

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7) In a third investigation, a student pulled the same heavy block a total of 4.5 m. This time, it was over a tiled floor. In this investigation, the force required to move the block was 4.5 N. Calculate the amount of work done.

Simple Machines

Simple machines are used to make work either ____________ or _____________. They cannot make work both ________________

and _____________.

Examples of simple machines:

o Ramps Makes the _________________ farther, but you have to use __________ force so the

work is easier, but takes _____________. If you were to lift the object straight up, you would use ___________ force and would

lift it a short distance. So, work is ____________, but faster. Diagram:

o Levers 25

Class 1 levers _____________ the direction of your force. That is, when you push _______________ on the lever, the load moves ___________.

Diagram:

]

Class 2 levers are used to make work ______________. You can move a very _____________ load using a fairly ____________ effort.

Diagram:

Class 3 levers are used to make work ______________. You usually move a very ___________ load with a ____________ effort force. This makes the load move very ______________.

Diagram:

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o Pulleys A pulley is a ______________ with a rope threaded around it. A fixed pulley __________ in one spot and simply changes the direction of your force. Diagram of a fixed pulley:

A moveable pulley actually _____________ with the load and allows you to lift a load using a __________ force. However, you have to pull _________ of rope to make the load move a ___________ distance.

Diagram of a moveable pulley:

o Wheel and axle If you turn the _____________ work is much easier. However, you have to turn a

__________ distance to do a small amount of work. Consider the steering wheel on a big transport truck…These trucks have very

__________ steering wheels that you have to turn a great distance to make the truck turn. Imagine if the steering wheel wasn’t there and you had to turn the axle…you would only have to turn a ____________ distance, but you would have to use a ___________ amount of force.

_________________________________________________________________ are all examples of wheel and axle.

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RUBE GOLDBERG PUZZLE ASSIGNMENT

PROBLEM: To catch a mouse in a mousetrap using all the different objects and machines that we have looked at in the Mechanical Systems unit.

PROCEDURE:1. Carefully cut out the 24 squares2. Working with your partner, solve the puzzle. Make sure the puzzle fits together in a logical

order to make sure the trap will fall on the mouse.3. When you think you have the puzzle figured out, ask the teacher to check it. You will be told

that it is either correct or that you need to make some changes.4. Once the puzzle is correct, glue your pieces down.5. Proceed to answer the questions on the back of your puzzle sheet.

ANALYSIS:1. Describe the entire process and how each item is used in catching the mouse.

2. What type of simple machine is a fan in #8?

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3. What type of simple machine is square #4?

4. What type of simple machine is square #20?

5. What type of simple machine is the cart on in #14?

6. What two types of simple machine are in square #11?

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Unit B Final Exam Review31

Unit B – Energy Transfer Technologies

Chapter 5

1) Explain what happens to particles when they are heated. Think about how they move.

2) When two materials are rubbed together, they heat up because of ______________.

3) Describe (using words or pictures) each of the following methods of heat transfer.a. Conduction

b. Convection

c. Radiation

3) Draw and explain a land breeze and a sea breeze.

Land Breeze Sea Breeze

4) Imagine you have the following two containers of water. Which container has more heat energy? Why?

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1L20oC

10L20oC

Chapter 6

5) Specific heat capacitya. What does this term mean?

b. If a substance has a high specific heat capacity, it heats and cools ________________.

c. If a substance has a low specific heat capacity, it heats and cools ________________.

d. Sand has a specific heat capacity of 2.5, while water has a specific heat capacity of 4.19. Which of the following will heat up 10oC the fastest?

i. 100mL sandii. 100mL wateriii. 500mL sandiv. 500mL water

6) What does the R-value of a substance tell you?

7) Calculate the total R-value of 25mm of air (R-value = 2.04) and 50mm of fibreglass (R-value = 4.25).

8) Explain the properties of a good insulator. In other words, what makes a material a good insulator?

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9) You are baking potatoes and are told that if you wrap them in tin foil they will bake faster…but you’re not sure if you should put the shiny side of the foil in or out. Which will make the potatoes bake faster? Why?

Chapter 7

10) Calculate, using the formula W=Fxd, to calculate how much work is done when you lift a 50N object 3m.

11) You push as hard as you can on a stuck car, but it doesn’t move. Even though you’re sweating and tired, you’re friend says you didn’t do any work. Is your friend correct? Why or why not?

12) Draw and give examples of different levers.a. First class

b. Second class

c. Third class

13) Energy is defined as ___________________________.

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