Temperature and Kinetic Energy Web Quest 8th Grade PSI...

www.njctl.org 8th Grade PSI Thermal Energy

Temperature and Kinetic Energy Web Quest

8th Grade PSI Science

Classwork 1 Name ____________________________________

Part I- Review how the molecules for a solid, liquid and gas differ at a constant

temperature.

1. Follow this link:

http://www.middleschoolchemistry.com/multimedia/chapter1/lesson5 . Scroll down

and click on the “Comparing Solids, Liquids and Gases” applet. Use the applet to

describe the characteristics of each state in the following table.

2. Based on your table. Label whether each statement describes a Solid (S), Liquid (L)

or Gas (G)

______There is a lot of free space between molecules as they are spread out all over

the place.

______It retains a fixed volume and shape.

______Molecules are not attracted to each other much at all.

______Molecules can move/slide past one another, yet still remain close together due

to their attraction to each other.

______Molecules are strongly attracted to one another.

State Attraction

between

molecules

Movement

between

molecules

Volume Shape

Solid

Liquid

Gas

http://www.middleschoolchemistry.com/multimedia/chapter1/lesson5


______Does not have a definite shape or volume.

______It has a definite volume but can change its shape to fit the container that it is

held in.

______Particles stay in fixed positions and vibrate in place.

Part II- Describe how the motion of molecules in various states compare when

substances are heated and cooled.

3. Let’s start by looking at a GAS. On the same webpage

(http://www.middleschoolchemistry.com/multimedia/chapter1/lesson5), scroll down

and click on “Heating Molecules of a Gas”. Use the applet to describe what

happens to the balloon when the air inside is heated and cooled. Use pictures and

words.

Why does this happen?

Heated (word description)

Heated (picture)

Cooled (word description)

Cooled (picture)



4. Now let’s look at a LIQUID.

Go to http://www.middleschoolchemistry.com/multimedia/chapter1/lesson2 . Scroll

down and click on “Heating and Cooling a Liquid”. Use the applet to describe what

happens to the water molecules when heated in pictures and words.


Heated (picture)


Cooled (picture)

Describe differences between what you saw in the liquid molecules compared to the gas

molecules:



5. Go to http://www.middleschoolchemistry.com/multimedia/chapter1/lesson4 . Scroll

down and click on “Heating and Cooling a Solid”. Use the applet to describe what

happens to the solid particles when heated in pictures and words.


Heated (picture)


Cooled (picture)

Describe how the motion of the solid molecules differs from the motion of the

gas molecules (from #2) and the liquid molecules (from #3) when heated.

6. Circle the correct word or phrase in parentheses that will make the statement true.

a. The molecular motion will (increase, decrease) when a substance is heated.

b. The molecular motion will (increase, decrease) when a substance is cooled.

c. When a substance is cooled, the kinetic energy of its molecules will

(increase,decrease).



d. The space between molecules gets (smaller, bigger) when a substance is

heated.

e. If the kinetic energy of a substance’s molecules decreases, then the substance is

being (heated, cooled) and the space between molecules gets (smaller, bigger).

f. Though molecules in a solid and a liquid will both experience a(n)

(increase,decrease) in kinetic energy when heated, the molecules in a (solid,

liquid) will always be (closer to, further from) one another when compared to

the molecules in a (solid, liquid) due to their strong attraction for one another.

Part III- Getting a “feel” for different temperature scales

7. Go to http://funphysics.jpl.nasa.gov/adventures/temperature-game.html

Read the instructions and then start by clicking on “Fahrenheit”. When you get a

match, fill in the temperature in Fahrenheit in the table below.

Once you’ve solved the puzzle, “close” the popup box. Click on Celsius and write

down the corresponding temperatures in the table below. Do the same thing for

Kelvin.

Icon Temperature

(Fahrenheit)

Temperature

(Celsius)

Temperature

(Kelvin)

Saturn

Death Valley

Freezing

Boiling Point

Space

Mars

Antarctica

Superfluid Helium

Room Temperature

Human Body

http://funphysics.jpl.nasa.gov/adventures/temperature-game.html


a. Which temperature scale gives the largest measurement for each

icon?____________________________ The

least?_______________________

b. What is the coldest item on your

table?_______________________________________

c. What is the hottest item on your

table?_______________________________________

8. On the same webpage, click on “More About Temperature” at the bottom. Read the

popup text and answer the following.

a. Which scale of temperature is used primarily in the United States?

b. Where is the Celsius temperature scale used?

c. What temperature scale do scientists use?

d. What is the international standard for scientific measurement of temperature?

e. Define absolute zero:

f. Define triple point:

g. What is the triple point in Kelvins?

h. Are divisions on the Kelvin scale referred to as “degrees”?

i. How many divisions are there on the Celsius scale?

j. What is the triple point in Celsius?

k. How do you convert from Celsius to Kelvin?

l. How do you convert from Kelvin to Celsius?

m. At what temperature does water boil in Celsius? In Kelvins? In Fahrenheit?

n. At what temperature does water at sea level freeze in Celsius? In Kelvins? In

Fahrenheit?

o. Write down the equation for converting Fahrenheit to Celsius:

p. Use the equation to convert 10°F to Celsius (show your mathematical work!). Use

the “automatic calculator” to check your answer:

q. Write down the equation for converting Celsius to Fahrenheit:

r. Use the equation to convert 27°C to Fahrenheit (show your mathematical work!).

Use the “automatic calculator” to check your answer.

s. Convert 90° C to Kelvins (show your mathematical work!). Use the “automatic

calculator” to check your answer.


Temperature and Kinetic Energy Review


Homework 1 Name ____________________________________

Fill in the blanks.

1. ____________________________________________ is directly proportional to

the average kinetic energy of molecules in matter.

2. If a substance is heated, its molecules __________________ up. Whereas if it is

cooled its molecules will ____________________ down.

3. Hot water molecules have ________________ kinetic energy than cold water

molecules.

4. Molecules in a solid ___________________ faster in position when heated.

5. The spacing between molecules in matter ___________________ when the

matter is heated.

6. Materials _________________________ when their temperatures increase and

______________________ when their temperatures decrease.

7. The Celsius scale has _____________divisions.

8. On the Celsius scale, the freezing point is _____________ and the boiling point is

____________.

9. On the Fahrenheit scale, the freezing point is __________________ and the

boiling point is __________.

10. The temperature scale that will always give the largest value when a substance’s

temperature is measured is _______________________.

Answer the following in complete sentences.

11. Describe the differences in the attraction between molecules for a solid, liquid and

a gas.

12. How will the motion of water molecules in hot soup differ from the motion of

water molecules in iced water?

13. If a substance has a temperature of absolute zero, what can you say about the

kinetic energy of the substance’s particles?

14. What are the differences between a thermometer that measures temperature on the

Kelvin scale and one that measures temperature on the Celsius scale?

15. Describe how a thermometer uses thermal expansion/contraction to measure

temperature.

16. Explain how the liquid level of an alcohol-based thermometer will be different

than the liquid level of a mercury based thermometer when heated. Why do the

liquid levels differ?


Show your work for the following conversions.

17. A person’s body temperature is measured at 38°C. Convert this temperature to

Fahrenheit.

18. The average temperature of a certain location is 286 Kelvin. Convert this

temperature to Celsius.

19. A piece of dry ice has a temperature of -78°C. What is its temperature in

a. Kelvin

b. Fahrenheit

20. Convert the following temperatures to the same temperature scale and order them

from coldest to warmest: 180 Kelvin, 75°C ,45°F.


Thermal Energy versus Temperature


Classwork 2 Name ____________________________________

Directions: For each pair of substances, state whether the kinetic energy (of molecules),

potential energy (of molecules) and temperature for substance A is greater than (>), less

than (<), or equal (=) to that for substance B. If there is not enough info to determine,

state “can not be determined”. Provide justification for each of your answer.

1. A: 2g piece of ice at -1°C

B: 2g piece of ice at -28° C

Kinetic Energy Temperature Potential Energy Thermal Energy

Justification:

Justification:

Justification:

Justification:

2. A: liquid water at 25 C

B: liquid water at 77 F


Justification:

Justification:

Justification:

Justification:


3. A: 8g of nitrogen gas at -150C

B: 2g of nitrogen gas at -150C


Justification:

Justification:

Justification:

Justification:

4. A: 1g of liquid water at 25C

B: 4g of liquid water at 30C


Justification:

Justification:

Justification:

Justification:

Summary questions:

5. Define kinetic energy.

6. What does temperature indicate about the motion of molecules or particles in a

substance?

7. How is potential energy related to molecules in matter?

8. Explain the difference between thermal energy and temperature.


Temperature and Thermal Energy


Homework 2 Name ____________________________________

Answer the following in complete sentences.

1. What is the difference between temperature and thermal energy?

2. How are temperature and thermal energy related?

3. Suppose there are two cups holding the same amount of water except one cup has

hot water and the other has cold water. They have different temperatures, but how

do they differ in the amount of thermal energy they possess?

4. Describe a scenario when two substances might have the same temperature, but

not the same amount of thermal energy.

5. If hot pizza sauce touches your cooler tongue, in which direction does the heat

flow? From your tongue to the sauce OR from the sauce to your tongue. Explain

why.

6. In which case will there be more energy transferred as heat:

a. 1 kg of water at 10°C in a freezer at -15°C

b. 1 kg of water at 60°C in an oven at 65°C

7. Why doesn’t thermal energy transfer between two substances with the same

temperature?

8. Describe the difference between a conductor and an insulator in terms of thermal

energy transfer and provide an example of each.

9. If you touch a metal spoon and then a wooden spoon that have the exact same

temperature, which is going to feel warmer to the touch and why? Hint, your hand

is warmer than both spoons.

10. Define the following methods of thermal energy transfer (heat):

a. Conduction

b. Convection

c. Radiation

11. How does radiation differ from conduction and radiation?

12. Which method of thermal energy transfer occurs best in solids and why?

13. Describe which methods of thermal energy transfer are involved when you sit by

a campfire roasting marshmallows.

14. Which method of energy transfer would occur if two objects of differing

temperatures were placed in a vacuum but were not touching each other?


Methods of Thermal Energy Transfer


Classwork 3 Name ____________________________________

Objective: Explore the three methods of heat transfer: conduction, radiation and

convection using online simulations and be able to identify examples of each.

1. Go to http://www.teachersdomain.org/asset/lsps07_int_heattransfer/ .

2. Read the introduction and then proceed to click on each type of heat transfer. For

each type of heat transfer, read the accompanying text and go through the

animation to see an example in action. Don’t forget to also click and view the

“Examples” tab. Complete the information in the attached table for each type of

heat transfer as you go.

3. Apply heat transfer methods to cooking by going here

http://www.scienceapplets.com/2012/10/summary-of-conduction-convection-

and.html. Scroll down until you see the “Summary of Conduction, Convection

and Radiation (with quiz)”. Click on the expand button on the bottom right hand

corner of the applet in order to expand the applet and take the quiz.

Describe the three examples in the quiz:

Radiation-

Convection-

Conduction-

http://www.teachersdomain.org/asset/lsps07_int_heattransfer/

http://www.scienceapplets.com/2012/10/summary-of-conduction-convection-and.html

http://www.scienceapplets.com/2012/10/summary-of-conduction-convection-and.html


4. Test your knowledge by completing the activity here

http://www.classzone.com/books/ml_science_share/vis_sim/mem05_pg119_heat/

mem05_pg119_heat.html

Write down your results in the table.

Conduction Examples Convection Examples Radiation Examples

Choose one example that you got incorrect on the first try and explain why it

actually belongs in the heat transfer category it is in.

http://www.classzone.com/books/ml_science_share/vis_sim/mem05_pg119_heat/mem05_pg119_heat.html

http://www.classzone.com/books/ml_science_share/vis_sim/mem05_pg119_heat/mem05_pg119_heat.html


Method of Heat

Transfer

Description Describe the animation Other examples

Radiation

Conduction

Convection


Thermal Energy Transfer Activity


Homework 3 Name ____________________________________

You have been learning about the three different ways that energy is transferred as heat:

conduction, radiation, and convection. This thermal energy transfer only occurs for two

substances or between two locations when there is a temperature difference. A mug of

hot cocoa that is left sitting out in a room exhibits all three methods of thermal energy

transfer: the cocoa loses heat by conduction through the cup’s sides (by direct contact

with cooler molecules), the cup’s surface loses heat by radiation as electromagnetic

waves are emitted and the air near the cup heats by convection as the air by the cocoa

warms, rises, cools and then sinks creating a small convection current.

Directions:

1. For one day, document and describe examples of conduction, radiation and

convection that you directly observed throughout the day.

2. Record your observations and descriptions on the attached sheets.

3. For each real life example, make sure to also identify which direction the heat

flowed.

4. You may supplement your work with diagrams and pictures.


Con

du

ctio

n

Con

vec

tion

R

ad

iati

on


Conductors versus Insulators

8th grade PSI Science

Classwork 4 Name ____________________________________

Objective: Use simulations to explore examples of conductors and insulators as they

relate to thermal energy transfer.

1. Go to http://www.sciencekids.co.nz/gamesactivities/keepingwarm.html and scroll

down until you see the simulation.

2. Insulate the beaker by choosing what you think is the best thermal insulator until

you are correct.

3. Now you will complete an online experiment in which you determine how

conductive (or how insulating) different materials are.

a. First, you are going to see how the liquid temperature changes with time

when the beaker is not wrapped with material.

b. Click the start button. At 10 minutes hit pause. It’s okay if you can’t hit

pause exactly at 10 minutes. Close to 10 minutes should be okay.

c. Remember the temperature of the liquid and then click on the “Table”

button at the bottom to record this temperature in the table.

d. Go back to the simulation by clicking on the “Activity” button.

e. Click the start button again. Hit pause at 20 minutes and record the

temperature again.

f. Repeat this until you have a temperature reading for 0,10,20,30,40,50,an

60 minutes in your table

g. Click on the “Reset” button below and repeat the entire experiment but

this time cover the beaker with “Polystrene”. Next you will repeat the

experiment with “Cardboard” and then “Metal Foil” so that your data table

is complete. Note, you will have to click “Reset” before experimenting

with each new material.

4. Click the button “Check” on the bottom to see if your data is correct. If you have

any incorrect data, the box will be red and you should redo that part of the

experiment to get the correct data.

5. Once your data is correct and completed, print it out or copy it on another sheet of

paper.

6. Using your data, rank the three materials tested from most conductive (closer to

the conductor end) to least conductive (closer to the insulators end).

http://www.sciencekids.co.nz/gamesactivities/keepingwarm.html


7. Now, let’s check out some other materials. Go here

http://www.scienceapplets.com/2012/06/conductors-and-insulators-game.html.

Scroll down until you see the “Conductors and Insulators” Game and then click

on the expand button in the bottom right hand corner of the game box

in order to expand and play the game. When you finish, the game, copy down the

correct answers.

http://www.scienceapplets.com/2012/06/conductors-and-insulators-game.html


Specific Heat (Math Skills)


Classwork 5 Name ____________________________________

Directions: Read each problem carefully. Work out the practice problems and show your

work clearly. Use the table of specific heats to help you.

Substance Specific Heat

(J/kg °C)

Aluminum 897

Apples 3,300

Bricks 800

Carbon 709

Copper 385

Gold 129

Iron 449

Mercury 140

Steam 1,870

Tin 230

Water 4,186

Wood 1,700

1. A 0.550 kg piece of copper is heated from 24°C to 45°C. How much thermal

energy does the copper absorb?

2. A 2kg piece of iron is heated and gains 6,620J of thermal energy. What is the

change in temperature of the piece of iron?

3. Determine the initial temperature of a 0.220 kg sample of tin when it is placed in

a container of water. The water gains 3700J of energy and the final temperature of

the tin is 19°C.

4. The specific heat of the human body is about 3300J/kg°C. How much thermal

energy is required to raise your temperature by 2°C? Assume an average body

mass of about 65kg.

5. A park bench made of iron has a mass of 135kg. On a warm day, its temperature

changes from 25°C to 35°C. How much thermal energy does the bench absorb?

6. The water in a small pond radiates 1 x 1010J of thermal energy during the night. If

the water’s temperature decreases by 5°C, what is the mass of the water in the

pond? HINT: Use the specific heat equation to solve for (m x c) and then divide

that answer by water’s specific heat capacity.

7. In order to cool a bowl of soup, you place several stainless steel spoons that have

been stored in the freezer in the bowl of hot soup. As a result, the soup’s

temperature changes from 82°C to 48°C. The mass of each spoon is 0.035kg and

the mass of the soup in 0.15kg. How much thermal energy is removed from the

soup? Since the soup is primarily made of water, use the specific heat of water

when you solve this problem.


8. What is the initial temperature of a 0.755kg piece of iron that absorbs 40,679J of

energy and if it’s final temperature is 403K?

9. A hot fluid is poured into a 0.40 kg drinking glass. 7,000J of thermal energy is

transferred from the fluid to the glass increasing the glass temperature by 22°C.

Determine the specific heat of the drinking glass. HINT: Use the specific heat

equation to solve for (m x c) and then divide that answer by the mass of the

drinking glass.

10. Water is cooled in a refrigerator by transferring 28,256 J of energy to the

refrigerator environment. If the mass of water is 0.225 kg, by how much does the

water change its temperature?


Specific Heat


Homework 4 Name ____________________________________

Answer the following in complete sentences and/or show your mathematical work. Use

the following specific heat table if necessary.

Substance Specific Heat

(J/kg °C)

Aluminum 897

Apples 3,300

Bricks 800

Carbon 709

Copper 385

Gold 129

Iron 449

Mercury 140

Steam 1,870

Tin 230

Water 4,186

Wood 1,700

1. Define specific heat.

2. What are the three variables that determine the amount of heat lost or gained

when a substance undergoes changes in temperature?

3. Suppose you have 0.10kg of cooked apples on an aluminum pan with the same

mass. Both the apples and the aluminum pan have the same temperature. Which is

most likely to burn your hand and why?

4. Why does the sand on a beach cool down more in the evening than the ocean

water?

5. Which of the following two objects will provide the most thermal energy: 2kg of

wood at 70°C or 2kg of bricks at 70°C? Explain.

6. a. What is the final temperature of 25kg of steam if it absorbs 800,000J of

energy. The initial temperature of the steam was 393K.

b. Repeat the above problem for 50kg of steam. Why is this answer different from

that in part a?

7. a. How much thermal energy is transferred if a 100kg container of water changes

its temperature from 25°C to 10°C.

b. How much thermal energy needs to transfer in order to cool that same

container of water from 25°C to 0°C? Why is this answer different from that in

part a?

8. A sample of copper and a sample of gold are heated in the same oven. Both

samples are identical in size and shape. After 10 minutes, which sample has the

higher temperature? Explain.


9. Your friend wants to see who can warm up a container a water over a campfire

first. Both waters are the same starting temperature but you have twice as much

water as your friend. Why does your friend have an advantage?

10. The temperature change of an object is:

a. _________________________ proportional to the object’s specific heat.

b. _________________________ proportional to the amount of energy

transferred to or away from the object.

c. _________________________proportional to the object’s mass.


Thermodynamics


Homework 5 Name ____________________________________

11. Define the following:

a. Thermodynamics

b. 1st law of thermodynamics

c. 2nd law of thermodynamics

d. entropy

e. heat engines

12. Provide an example of the 1st law of thermodynamics.

13. Draw a schematic diagram explaining how an internal combustion engine works.

14. Choose ONE of the following examples of a heat engine and research how it

works online. Create a diagram of your chosen heat engine that explains how it

works.

Refrigerator

Heat Pump

Air Conditioners

Diesel Engine

Steam Engine

Hurricanes as Heat Engines


Classwork 6 Name ____________________________________

Teacher notes: This activity is a pre-written activity by NASA where students see a real

life application of heat engines as well as develop reading, data analysis and research

skills. All instructions and links can be found here:

http://mynasadata.larc.nasa.gov/lesson-plans/lesson-plans-middle-school-

educators/?page_id=615?&passid=50

A brief summary of what students will do:

1. Examine path of Hurricane Rita (Sept 18-24, 2005, Category 5 hurricane)

2. Create daily data maps and time series plots of the sea surface temperature (SST)

for the Gulf of Mexico DURING and AFTER the passage of Hurricane Rita using

a Live Access Server.

http://mynasadata.larc.nasa.gov/lesson-plans/lesson-plans-middle-school-educators/?page_id=615?&passid=50

http://mynasadata.larc.nasa.gov/lesson-plans/lesson-plans-middle-school-educators/?page_id=615?&passid=50


Temperature and Kinetic Energy Web Quest Answer Key

1. Answers may vary slightly

2. G, S, G, L, S, G, L, S



Balloon expands

Heated (picture)


Balloon shrinks

Cooled (picture)

This happens because when the molecules of the gas (air) are heated, they move

faster, spread out and thus push out on the balloon. When the air is cooled, the

molecules move slower, aren’t spread out and don’t push out on the balloon as

much so it shrinks.



Molecules move faster and spread slightly

apart

Heated (picture)


Cooled (picture)

State Attraction

between

molecules

Movement

between

molecules

Volume Shape

Solid

Very strong

attraction

Molecules stay

in fixed position

but vibrate

Definite volume Definite shape

Liquid

Attracted, but

less than solid

molecules

Molecules can

slip and flow

past each other

Definite volume Takes on shape

of container

Gas

Molecules are

not attracted to

each other much

(the least of all 3

states)

Molecules can

easily move past

each other

No definite

volume

No definite

shape


Balloon shrinks

Molecules don’t move as fast and are

therefore closer together.

Liquid molecules, being more attracted to each other than gas molecules, do not

spread out as much when heated.



Particles vibrate faster and move slightly

apart

Heated (picture)


Particles vibrate less and are closer together

Cooled (picture)

Solid molecules, being the most attracted to each other than either liquid or gas

molecules, do not spread out nearly as much as gas/liquid molecules when heated.

The molecules are not free to move and thus tend to vibrate more when heated

rather than slip past each other.

6. a. increase

b. decrease

c. decrease

d. bigger

e. cooled, smaller

f. increase, solid, closer to, liquid

7.

Icon Temperature

(Fahrenheit)

Temperature

(Celsius)

Temperature

(Kelvin)

Saturn -229

-145 128

Death Valley 134

56 324

Freezing 32

0 273

Boiling Point 212

100 373

Space -454.54

-270 2.70

Mars -81

-63 210


Antarctica -128

-89 183

Superfluid Helium -455.76

-271 2.17

Room Temperature 68 20 293

Human Body 98.6

37 310

a. Kelvin, Fahrenheit

b. Superfluid Helium

c. Boiling Point

8. a. Fahrenheit

b. everywhere else but US

c. Kelvins

d. Kelvin Scale

e. absolute zero: the theoretical coldest temperature there could possibly be

f. triple point: the point at which water co-exists as a solid, liquid and a gas in

equilibrium

g. 273.16 Kelvin

h. no

i. 100

j. 0.01 °C

k. add 273.15

l. subtract 273.15

m. 100°C, 373.15 Kelvin, 212°F

n. 0°C, 273.15 Kelvin, 32°F

o. C=5/9(F-32)

p. -12.22 °C

q. F= (9/5C)x 32

r. 80.6 °F

s. 363 Kelvin


Temperature and Kinetic Energy Review

Answer Key

1. temperature

2. speed, slow

3. more (or higher)

4. vibrate

5. increases

6. expand, contract

7. 100

8. 0 degrees Celsisus, 100 degrees Celsius

9. 32 degrees Fahrenheit, 212 degrees Fahrenheit

10. Kelvins

11. In a solid, molecules are the most attracted to each other which means

molecules are more or less in a fixed position. Molecular attraction in a

liquid is less than that of a solid but more than that of a gas allowing

molecules to slide and flow past each other. Gases have the weakest

molecular attraction and gas molecules move easily and freely past each

other.

12. Hot soup water molecules move faster than cold water.

13. The kinetic energy of a substance with a temperature of absolute zero is

near zero. There is little to no motion.

14. They differ by 273degrees. For example, 0 degrees Celsius corresponds to

273 Kelvin, the freezing point of water.

15. When the liquid inside a thermometer is heated, it will expand. Since the

liquid in a thermometer is encased in a narrow tube, the amount of

expansion is easily visible and can be measured. The same principle works

when the liquid inside the thermometer is cooled. In this case the liquid

will contract and the liquid level will go down reflecting a decrease in

temperature.

16. The alcohol level will be higher than the mercury level because the alcohol

molecules are not as attracted to each other as the mercury molecules.

When heated, this allows for the alcohol to experience more thermal

expansion.

17. 100.4 degrees Fahrenheit

18. 13 degrees Celsius

19. a) 195 Kelvin b) -108.4 degrees Fahrenheit

20. In degrees Celsius: -93, 75, 7.22 (in order -93, 7.22, 75)

In degrees Fahrenheit:-135.4, 167, 45 (in order -135.4, 45, 167)

In Kelvins: 180, 348, 280 (in order 180, 280, 348)


Thermal Energy versus Temperature

Answer Key

1. A: 2g piece of ice at -1° C

B: 2g piece of ice at -28°C


>

Justification:

Higher temp

>

Justification:

Higher temp

>

Justification:

Molecules are

farther apart

because the

temperature is

more

>

Justification:

KE is more AND

PE is more, so TE

is more

2. A: liquid water at 25 C

B: liquid water at 77 F


=

Justification:

They actually have

the same

temperature (have

to convert)

=

Justification:

They actually have

the same

temperature (have

to convert)

=

Justification:

Same temperature,

same state.

Can not be

determined

Justification:

Do not know how

much liquid there

is so do not know

how much total

molecular energy.

3. A: 8g of nitrogen gas at -150C

B: 2g of nitrogen gas at -150C


=

Justification:

Same temperature

=

Justification:

Same temperature

=

Justification:

Same temp, same

state

>

Justification:

There are more

nitrogen gas

molecules due to

the larger mass so

more total


molecular energy.

4. A: 1g of liquid water at 25C

B: 4g of liquid water at 30C


<

Justification:

Has a lower

temperature

<

Justification:

Has a lower

temperature

<

Justification:

Has a lower temp,

so molecules are

closer and therefore

the liquid has less

PE

<

Justification:

There is less liquid

water in case “A”

as well as less

kinetic energy so

there is less total

molecular energy

overall.

Summary questions:

5. Define kinetic energy.

Energy of motion

6. What does temperature indicate about the motion of molecules or particles in a

substance?

The higher the temperature, the faster the molecules and vice versa.

7. How is potential energy related to molecules in matter?

It is related to the attractive forces between molecules in matter. The further away

molecules are from being where they want to be (i.e. close together in a solid),

then the more potential energy there is.

8. Explain the difference between thermal energy and temperature.

Temperature is the average kinetic energy of molecules whereas thermal energy is the

TOTAL molecular energy of a substance.


Temperature and Thermal Energy

Answer Key

1. Temperature is proportional to the average molecular kinetic energy. Thermal

energy is the total molecular kinetic and potential energy.

2. Temperature and thermal energy are directly proportional IF the amount of

substance in question is the same.

3. The hotter water will have more thermal energy because it has more kinetic

energy (due to its higher temperature) and it has more potential energy, as the

spacing between water molecules is slightly greater.

4. A big bowl of soup and a small cup of soup may have the exact same

temperature or average molecular kinetic energy. But the bowl has more soup

molecules overall, so it has more thermal energy than the small cup of soup.

5. Heat flows from the sauce to the tongue because heat flows from hot to cold

and the sauce is hotter than the tongue.

6. Case ‘a’ will have more energy transfer because there is a larger temperature

difference between the water and the environment.

7. Two objects at the same temperature do not exchange heat because they are in

thermal equilibrium.

8. A conductor is a material that easily allows for thermal energy transfer while

an insulator is a material that does not. An example of a conductor is

aluminum while an example of an insulator is cloth.

9. The wooden spoon will feel warmer because it is not as good a conductor as

the metal spoon. In fact wood is an insulator. This means, energy is

transferred less efficiently from your hand to the wooden spoon compared to

when you touch the metal spoon. This means your hand cools less efficiently

when you touch the wooden spoon, so the metal spoon feels cooler.

10. a. Heat transfer through direct contact

b. Heat transfer from the movement or circulation of fluids or gases of

different temperature.

c. Heat transfer via electromagnetic radiation.

11. It does not require a medium for thermal energy transfer.

12. Conductors because molecules are closer together allowing thermal energy to

transfer from molecule to molecule easily.

13. Radiation- from the warmth of the fire

Conduction- marshmallows touch the fire

Convection- air above fire experiences convection currents (sparks)

14. Radiation


Methods of Thermal Energy Transfer

Answer Key

2. answer key for table is attached

3. Radiation- when the grill gets hot, it emits infrared radiation that travels through the

air and is then absorbed by the bacon.

Convection- water molecules near the bottom heat, rise, cool down at the top and then

sink starting the cycle over and creating a convection current until all the water is heated.

Conduction- As the pan heats, its molecules heat and start to vibrate. These vibrating

molecules transfer their energy through the pan to the food. The food molecules in

contact with the pan therefore start vibrating (heat up).

4.

Choose one example that you got incorrect on the first try and explain why it actually

belongs in the heat transfer category it is in.

Answers will vary


Method of Heat

Transfer

Description Describe the animation Other examples

Radiation

Answers may vary some:

Transfer of energy along electromagnetic waves

When the wave comes into contact with an

object, the energy is transferred

Radiation is the only heat transfer method that

can travel through empty space.

Electromagnetic waves from the

sun travel through the air and

reach the house. The house

absorbs this thermal energy and

the temperature inside the house

increases.

Camp fire

Microwave oven

Light bulb

Human body

Conduction


Transfer of thermal energy between things that

are in direct physical contact

Heat flows when molecules in one object that

are vibrating cause molecules in a neighboring

object to vibrate

Works best in solids because particles are close

together

Doesn’t work as well in liquids and less so in

gases due to the spacing of particles

The molecules in the burner heat

up and vibrate causing the

molecules in the bottom of the pot

to vibrate because they are

touching. These vibrations

(thermal energy) go through the

entire pot. When the person

reaches to touch it, the energy

from the vibrations of the

molecules in the pot handle are

transferred to the molecules in the

hand. Ouch!

Metals are good

conductors (get hot and

cold quickly because

thermal energy propagates

through them quickly)

Air and gases are not good

conductors because

thermal energy does not

transfer easily from

molecule to molecule as

they are spaced apart.

Convection


Transfer of heat by movement through a medium

such as air or liquid

Primary heat transfer method for gases and

liquids

When a gas or liquid is heated, the liquid

expands and rises because it is less dense.

When the medium cools, it sinks because it is

The stove is lit warming the air

around in. This air rises because it

less dense but then cools as it gets

farther away from the stove. This

cool air then sinks close to the

stove where it is warmed again and

rises creating a convection current.

Water boiling

Hot air balloon

A building (attic is warmer

than a basement)


denser.

The cycling of a hot medium rising and a cold

medium sinking creates a convection current.

Thermal Energy Transfer Activity

Answer Key

Answers will vary from student to student.

Conductors versus Insulators

Answer Key

5.

6. Metal foil, cardboard, polystyrene

7.


Specific Heat (Math Skills)

Answer Key

1. 4446.75 J

2. 7.37 °C

3. 54 °C

4. 4.29 x 105J

5. 6.06 x 105J

6. 4.78 x 105kg

7. 21,349J

8. 283K

9. 795 J/kg °C

10. 30°C

Specific Heat

Answer Key

1. The amount of energy needed to raise the temperature of 1kg of a substance by 1

degree Celsius.

2. Mass, specific heat capacity, and the change in temperature

3. The apples. Since the apples have a larger specific heat capacity, it required more

thermal energy to bring the apples to the same temperature as the aluminum. This

larger amount of thermal energy will transfer to your hand if you touch it since

your hand is cooler.

4. Sand has a lower specific heat than water. It gains more thermal energy during the

day and loses more at night.

5. Wood because it has a higher specific heat than bricks.

6. a. 410 Kelvin

b. 401 Kelvin. It is less because there is more mass to heat.

7. a. 6.3 x 106J

b. 1.0 x 107J More thermal energy is required because the temperature change is

greater.

8. Gold will have a higher temperature because it has a lower heat capacity meaning

it requires less energy to change its temperature than copper.


9. Mass is inversely proportional to temperature change. More water yields a lower

change in temperature.

10. a. inversely

b. directly

c. inversely

Thermodynamics

Answer Key

1. a. the branch of science that studies how heat and work are related

b. the law of conservation of energy- energy can not be created or destroyed

c. heat flows from warmer to colder and all systems increase their disorder

d. a measure of the amount of disorder in a system

e. something that converts heat to mechanical energy

2. Answers will vary

3. Answers should reflect animated gif from SMART notebook slide 95: air and fuel

are drawn in, piston moves and compress air-fuel mix, fuel combusts and expands

and pushes down on piston, exhaust is driven out.

4. Answers will vary. Sample outcome:

Image from http://researchthetopic.wikispaces.com/


Hurricanes as Heat Engines

Examples of output you should expect to see when your students do this activity.

Possible SST maps for DURING Rita


Possible SST maps for AFTER


SST Time Series

Analysis

Students should see that there is large drop in sea surface temperatures after the hurricane

has passed. This is because the hurricane draws in warm moist ocean surface/air and uses

it almost like fuel. This “fuel” is converted to heat energy in the thunderstorms that form

around the hurricane eye. This heat refuels the hurricane. SSTs drop because the

hurricane “uses” up the warm surface waters to fuel itself. Often, water from deeper in

the ocean upwells to replace the surface waters.

Temperature and Kinetic Energy Web Quest 8th Grade PSI...

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