Science 7 Unit C

Heat and Temperatur

eTopics 4&5

1

Pg. 210 - 225

2

Name:

In this module we will explore:• The link between different heating technologies and human needs; • The reaction of different materials and devices when temperature changes; • The regulation of the transfer of energy for electronic devices • The particle model of matter and the explanation it gives of the effect of temperature

and heat on solids, liquids and gases; • The advantages and disadvantages related to the use and regulation of energy;• Personal and collective choices related to the use and conservation of energy.

By the end of this module, you should be able to define each of the following terms in your own words.

Advice:

- Write the definition for the term after you see it. - It’s worth it to write it in your own words. This way you’re more likely to remember it.

Topic 1/2

- Thermometer- Scales- Sensor- Signal- Responder- Celsius scale- Fahrenheit scale- Kelvin scale

Topic 3

- Particle model of matter

- Temperature- Energy- Thermal energy

Topic 4- Expand- Contract

Topic 5

- Solid- Liquid- Gas- Fusion- Melt- Freeze- Solidification- Evaporation- Boiling- Condensation- Sublimation

Topic 6

- Source of energy- Radiation- Thermal

conduction- Insulation

- Fluid- convection

Topic 7

- Chemical energy- Electrical energy- force- Geothermal

energy- Solar energy- Passive solar

heating- Active solar

heating- Wind energy- Energy resources- Fossil fuels- Non-renewable

resources- Renewable

resources

3

Topic 4: Expansion and ContractionObjective:

I can describe the effect of temperature on the movement of particles I can distinguish between heat and temperature I can describe the effects of increasing and decreasing the temperature on the volume of

different materials

Read the “Did You Know?” on pg. 210 and answer the following questions: What two things do not have the same properties as matter?

Are these forms of energy?

Expansion and Contraction

The Particle Model of Matter tells us that as materials ______________ their particles move _________ and _______________. • This causes the material to _____________.

• Expand: _____________________________________

As materials _________________ the particle model of matter says that their particles move ____________ and _______________________. • This causes the material to ________________.

• Contract: _____________________________________

States of Matter• There are 3 common states of matter

____________: The material keeps both their _________ and _________. Solids ____________ be compressed.

____________: The material has a __________________ (size), but no _____________. Liquids ____________ be compressed significantly.

4

____________: The material has ________________________ ________________. Gases can ___________ be compressed into a smaller space because there is a ____________________ __________ between the particles.

How do particles move in a…

1. Solido With _______________

2. Liquido By _______________

3. Gaso ____________ all over the place

5

Expansion and Contraction of Solids

All solids contract and expand at ________________________ .• They have a defined __________ and ______________.• They cannot be __________________________________________.

• Civil engineers have to think about _________________________________ when planning roadways, sidewalks, and bridges.

• The expansion of solids is very ___________ compared to ___________ and _________ due to the ________________________ between particles

Expansion and Contraction of Liquids

• They have a defined ______________ but not a defined form• They cannot be _______________ • When the temperature of a liquid ___________, the particles

___________• _______________________, causing the substance to expand.

• Different liquids expand and contract at _______________________.

• A common example of the expansion and contraction of liquids is the ____________________________.

6

Expansion and Contraction of Gases • Most gases are __________________, so they are difficult to

observe.• Because gases always take the

________________________________ it is difficult to observe their expansion and contraction.

• If you put gases in a ______________________ such as a balloon, however, you can see that they expand and contract __________________________.

Plasma• There is a fourth state of matter called plasma.• For a material to change into the plasma state requires

________________ _______________________, like those inside the sun.

• In plasma, individual particles that make up the material start to _________ __________ into tinier pieces called _______________________.

Topic 4 Review pg. 217

1). Name the three states of matter. Give examples of three substances that are each in a different state at room temperature.

2). From your observations in this topic, write a general description of what happens to solids, liquids and gases as they are

a. warmed

7

b. cooled

3). Which state of matter shows the largest change in volume when warmed or cooled?

Which state shows the smallest change? 4). The graphs to the side show the volume of mercury in a thermometer.

a. Which graph could be called a warming graph? Explain why.

b. Which graph could be called a cooling curve? Explain why.

c. Which graph shows what happens as soon as a thermometer is placed in hot soup? Why?

d. Which graph shows what happens as soon as a thermometer is placed in ice cream? Why?

5). Bridges are made from materials that expand and contract as the temperature changes. The photographs below show an expansion joint between components of a bridge in winter and in summer.

a. Which season is shown in each picture? Explain how you know.

b. Why do you suppose concrete roadways and sidewalks are laid in sections with small gaps

8

between them?

Science Focus 7Topic 4 SOLIDS, LIQUIDS & GASES

CONCEPT: Solids, liquids and gases expand when their temperature increases and contract when their temperature decreases.

A. SOLIDS1. Why is it important to place gaps at regular intervals in sidewalks?

2. Concrete and steel expand at almost the same rate. Explain why this is important in the construction of tall buildings.

B. GASES3. Explain how a hot air balloon is lifted from the ground.

4. Draw a diagram of the balloon rising into the air. Include arrows to show how the gas particles are moving in and around the balloon.

5. When the balloon is up in the air, the burner is turned off and the balloon drifts along with the wind. What will eventually happen to the air inside the balloon?

9

C. LIQUIDS6. A bowl of hot soup was left on the table to cool. After a few minutes, the

amount of soup in the bowl appeared to have decreased. Why?

7. When manufacturers pack liquids into bottles and jars, they leave a small space at the top before putting on the lids. Why?

8. Mercury expands and contracts faster than alcohol. Which liquid would be better in a thermometer. Why?

10

EXPANSION AND CONTRACTIONComplete the word search by finding all the words listed below. Circle each word you find.

ATTRACTION MASS SOLIDSCHANGES MATTER STATESCONTRACT MOVE STRETCHEXPAND PARTICLES TEMPERATUREFASTER PHASES VOLUMEGASES SHRINKLIQUIDS SLOWER

11

Heat and Temperature Practice Quiz Topic 4 — Expansion and Contraction

1. When a substance is heated the particles gain energy and spread out, creating more volume (spaces between the particles. So what about the mass of the substance? What happens to the mass of a substance when it is heated?

A. Mass increases B. Mass decreases C. Mass remains the same D. Mass is lost

2. Solids made of different metals were all heated to 100°C to determine how their volume and length would be affected. Which statement describes the most likely outcome of this experiment?

A. All the volumes changed the same amount and the lengths remained constant. B. All the volumes changed, but each substance was the same length. C. Only some of the volumes changed with their length being increased. D. All of the volumes changed and so did their lengths.

3. Some students performed an experiment testing the affect of heat on different liquids. Which of the following variables would have been the manipulated variable?

A. The amount of heat used B. The size and type of glass tubing each liquid would rise C. The different types of liquids D. The different levels each of the liquids reached in the glass tubing

4. Look at the experiment that the students set up to determine if a gas expands when heated. The experiment didn’t work because the students were missing an important element to get the results they predicted. What was missing?

A. Proper safety equipment

B. A larger balloon

C. A larger flask was needed

D. A heat source

5. A balloon filled with helium was put into a freezer to determine what the effect the lowering of the temperature would have on a gas. The responding variable in this experiment was the

A. amount of gas in the balloon before and after B. the volume of the balloon before and after C. the temperature variation of the freezer D. the amount of time needed to change the balloon

12

Topic 5: The Particle Model and Changes of State

Objectives:

I can compare the transmission of heat to different materials. I can explain changes in states using the Particle Model of Matter.

We learned that different materials expand by ___________________ as they warm up.

- Another difference in the way materials respond when they are heated is the ____________________________ when a certain amount of ________ _____________ is added.

- Some materials warm and cool ___________ while others warm and cool _____________.

Heat Capacity vs. Specific Heat Capacity

Definition

Describes

Depends on

• Material with a low specific heat capacity will have ____________________ _________________ when heated or cooled.

13

• Material with a high specific heat capacity will have ____________________ ___________________ when heated or cooled.

Activity: Hot Stuff! pg. 219

Part 1Questions 1 & 2

Substance Rate of temperature change

Specific heat capacity

Sand from the beach

Water from a lake

Questions 3 & 4Substance Rate of temperature

changeSpecific heat

capacityThe bottom of a pan

Ice pack that is used to treat athletes

The dried glue from a glue gun

Part 2

5.

6.

14

7. Changes of State

• A change of state requires the input of energy in one direction and a release of energy in another.

• _________ _________ __________ (energy is used)

• _________ _________ __________ (energy is released)

Melting (fusion): Freezing (solidification):

Note: _________________ and _________________ of a material are the _______________________. The difference is whether energy is being ________ (__________) or whether it is being _____________ (__________________).Evaporation: Condensation:

Note: ________________ and __________________ occur at the ________________________. The difference is whether energy is being ___________ (___________________) or whether it is being _____________ (_________________).Sublimation: The process in which a ______________________________________ _________________ without passing through the liquid stage.

15

What is happening to the particles during a change in state? • The _______________ of the particles changes • When the energy ___________, the particles become

_____________• The ________ energy of a substance

__________________________ (diagonal lines on a graph) • The ____________ energy of the particles does not

change therefore the ________________ does not change (horizontal lines on a graph)

Melting and Boiling Points

• Why is it important to know the melting and boiling points for different substances?• To ____________________ • To know ___________a change in state will occur

Do all substances have the same melting and boiling point?

Evaporative Cooling• In a liquid, particles are moving at

_________________________________.• Some of the faster-moving particles at the _______________

are able to ____________________________.• The absence of these faster-

moving particles _________________________ of the water, and the _____________________________.

Evaporative Cooling Summary:16

The “Plateau Problem”

Why doesn’t the temperature change during a _________________ (change of state)?• During a phase change the ___________________________

(temperature) stays _______________.• What does change is the _________________ of the particles.

Particles become ________ organized as their energy _____________, so substances change from _______ to _________ to _________.

Particles become _________ organized as their energy ____________, so substances change from ______ to __________ to __________.

During a phase change energy is being used to _____________________ between particles, not ________________________. • This energy change is ______________________ (no temperature

change) so it is called “hidden heat” or “_________________”.17

Activity: Learn the Lingo

1. Label the diagram below using the terms for the six different changes of state.

2. Read each statement below. Then write a description of each statement, using a technical term, as in the example.

Example: Wet clothes dry in the sunshine.Description: evaporation of liquid water

(a)Melted wax in a candle hardens when the candle is blown out.Description: ________________________________________________________

(b)A warm wind make snow on the ground disappear, but no puddles of water form.Description: ________________________________________________________

(c) In the winter, invisible moisture in the air sometimes forms frost on car windshields. Description: ________________________________________________________

(d)On a cold day, you can “see your breath”. Description: ________________________________________________________

3. Classify the six changes of state according to the change of thermal energy they involve. Arrange your answers in a table, with the headings “receiving thermal energy” and “releasing thermal energy”.

Receiving Thermal Energy

Releasing Thermal Energy

18

EXPANSION AND CONTRACTIONComplete the word search by finding all the words listed below. Circle each word you find.

ATTRACTION MASS SOLIDSCHANGES MATTER STATESCONTRACT MOVE STRETCHEXPAND PARTICLES TEMPERATUREFASTER PHASES VOLUMEGASES SHRINKLIQUIDS SLOWER

19

Activity: Hidden Heat

“Hidden heat” is a term used to describe the quantity of energy that slows into a substance as its state changes, without changing its temperature. The graph below is called a heating curve. It shows the temperature change that occurred when a block of ice was heated in an experiment.

Use the graph to answer the following questions about this experiment.

1. (a) At what time did the ice begin to melt?

(b) How long did the ice take to melt completely?

(c) What does a plateau in the graph indicate about the temperature?

20

(d) Describe the temperature change during the plateau. Where has all the added energy gone?

2. (a) Once the ice melted into water, what happened for the next 5 minutes?

(b) What occurred 8 minutes into the experiment?

(c) What does the second plateau in the graph represent?

3. Suppose the vapour was cooled in a freezing compartment where the internal temperature was -10˚C. In the space below, sketch and label what the cooling curve might look like.

21

Heat and Temperature Practice Quiz Topic 5 — The Particle Model and Changes of State

1. The sun shines down on the banks of a river (and the river itself). The thermal energy absorbed will be

A. more in the water B. more in the soil C. almost the same in both D. dependant on the mass of each

2. When a substance undergoes a change of state, energy is involved. Which change of state involves a release of energy?

A. Melting B. Sublimation C. Evaporation D. Fusion

3. As high-energy particles escape from the surface of a liquid, by evaporation, the remaining liquid cools. This surface cooling phenomenon is described by scientists as

A. evaporative cooling B. subliminal cooling C. fusion D. condensive evaporation

4. During a phase change, the temperature remains the same, so the particles have

A. less average energy B. more average energy C. the same average energy D. a faster speed

5. The water droplets that form on a bathroom mirror have undergone a phase change. Prior to the droplets forming, the water was in a state of

A. absolute flux B. suspended animation C. liquid D. gas

22

Topic 4 & 5 Practice Test/15

1. From the following list of words, choose the BEST word to go in the blanks (1 mark each).

moreless

sublimation

condensation

expandgainsfusion

contract

gasliquidsolid

plateauloses

evaporation

a) When we add energy to solids, they __________________ in size.

b) The state of matter that shows the largest change in volume when warmed and cooled is __________________.

c) When liquids are cooled, they __________________ in size.

d) The flat, horizontal line on a graph is called a __________________.

e) When a substance changes from a gas to a liquid, it is going through ________________.

f) When a substance changes from a solid to a liquid, it is going through _______________.

g) When a substance changes from a solid to a gas, it is going through _________________.

h) Particles become __________________ organized when a substance changes from a liquid to a gas.

i) Particles become __________________ organized when a substance change from a liquid to a solid.

j) A substance __________________ energy when it changes from a solid to a liquid.

2. True/False (1 mark each)

a) _____ All liquids expand at the same rate.

b) _____ Water has a very high specific heat capacity

c) _____ When a substance changes from a gas to a solid, it is going 23

through solidification.

d) _____ Evaporation cools a liquid because the slower moving particles escape from the surface

e) _____ When water changes states, its temperature remains the same.

24