Temperature and KE Classwork
Classwork #1
Name: _______________________________
8th Grade PSI
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.
State
Attraction
between
molecules
Movement
between
molecules
Volume
Shape
Solid
Liquid
Gas
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.
______
Does not have a definite shape or volume.
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8th Grade PSI
Thermal Energy
______
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.
Heated (word description)
Heated (picture)
Cooled (word description)
Cooled (picture)
Why does this happen?
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8th Grade PSI
Thermal Energy
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 (word description)
Heated (picture)
Cooled (word description)
Cooled (picture)
Describe differences between what you saw in the liquid molecules compared to the
gas molecules:
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Thermal Energy
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 (word description)
Heated (picture)
Cooled (word description)
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.
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8th Grade PSI
Thermal Energy
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
Temperature
Temperature
(Fahrenheit)
(Celsius)
(Kelvin)
Saturn
Death Valley
Freezing
Boiling Point
Space
Mars
Antarctica
Superfluid Helium
Room
Temperature
Human Body
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8th Grade PSI
Thermal Energy
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.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
l.
m.
n.
o.
p.
q.
r.
s.
Which scale of temperature is used primarily in the United States?
Where is the Celsius temperature scale used?
What temperature scale do scientists use?
What is the international standard for scientific measurement of temperature?
Define absolute zero:
Define triple point:
What is the triple point in Kelvins?
Are divisions on the Kelvin scale referred to as “degrees”?
How many divisions are there on the Celsius scale?
What is the triple point in Celsius?
How do you convert from Celsius to Kelvin?
How do you convert from Kelvin to Celsius?
At what temperature does water boil in Celsius? In Kelvins? In Fahrenheit?
At what temperature does water at sea level freeze in Celsius? In Kelvins? In
Fahrenheit?
Write down the equation for converting Fahrenheit to Celsius:
Use the equation to convert 10°F to Celsius (show your mathematical work!). Use
the “automatic calculator” to check your answer:
Write down the equation for converting Celsius to Fahrenheit:
Use the equation to convert 27°C to Fahrenheit (show your mathematical work!).
Use the “automatic calculator” to check your answer.
Convert 90° C to Kelvins (show your mathematical work!). Use the “automatic
calculator” to check your answer.
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8th Grade PSI
Thermal Energy
Temperature and KE Homework
Homework #1
Name: __________________________
8th Grade PSI
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
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8th Grade PSI
Thermal Energy
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.
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8th Grade PSI
Thermal Energy
Thermal Energy vs Temp Classwork
Classwork #2
Name: __________________________
8th Grade PSI
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
Kinetic Energy
Temperature
Potential Energy
Thermal Energy
Justification:
Justification:
Justification:
Justification:
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8th Grade PSI
Thermal Energy
3. A: 8g of nitrogen gas at -150C
B: 2g of nitrogen gas at -150C
Kinetic Energy
Temperature
Potential Energy
Thermal Energy
Justification:
Justification:
Justification:
Justification:
4. A: 1g of liquid water at 25C
B: 4g of liquid water at 30C
Kinetic Energy
Temperature
Potential Energy
Thermal Energy
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.
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8th Grade PSI
Thermal Energy
Temp. and Thermal Energy Homework
Homework #2
Name: ________________________
8th Grade PSI
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?
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8th Grade PSI
Thermal Energy
Methods of Thermal Energy Transfer Classwork
Classwork #3
Name: ____________________
8th Grade PSI
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-convectionand.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-
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8th Grade PSI
Thermal Energy
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.
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8th Grade PSI
Thermal Energy
Method of Heat
Transfer
Description
Describe the animation
Radiation
Conduction
Convection
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8th Grade PSI
Thermal Energy
Other examples
Thermal Energy Transfer Homework
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.
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8th Grade PSI
Thermal Energy
Conduction
Convection
Radiation
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8th Grade PSI
Thermal Energy
Conductors vs Insulators Classwork
Classwork #4
Name: __________________________
8th Grade PSI
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).
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Thermal Energy
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.
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8th Grade PSI
Thermal Energy
Specific Heat Classwork
Classwork #5
Name: ____________________________
8th Grade PSI
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
Aluminum
Apples
Bricks
Carbon
Copper
Gold
Iron
Mercury
Steam
Tin
Water
Wood
Specific Heat
(J/kg °C)
897
3,300
800
709
385
129
449
140
1,870
230
4,186
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.
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8th Grade PSI
Thermal Energy
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?
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8th Grade PSI
Thermal Energy
Specific Heat Homework
Homework #4
Name: _____________________________
8th Grade PSI
Answer the following in complete sentences and/or show your mathematical work. Use
the following specific heat table if necessary.
Substance
Aluminum
Apples
Bricks
Carbon
Copper
Gold
Iron
Mercury
Steam
Tin
Water
Wood
Specific Heat
(J/kg °C)
897
3,300
800
709
385
129
449
140
1,870
230
4,186
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.
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8th Grade PSI
Thermal Energy
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.
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8th Grade PSI
Thermal Energy
Thermodynamics Homework
Homework #5
Name: ____________________________
8th Grade PSI
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.





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Refrigerator
Heat Pump
Air Conditioners
Diesel Engine
Steam Engine
8th Grade PSI
Thermal Energy
Hurricanes as Heat Engines Classwork
Classwork #6
Name: ___________________________
8th Grade PSI
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-schooleducators/?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.
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8th Grade PSI
Thermal Energy
Answer Key
Temperature and KE CW #1
Answer Key
1. Answers may vary slightly
State
Attraction
between
molecules
Very strong
attraction
Solid
Attracted, but
less than solid
Liquid
molecules
Molecules are
not attracted to
Gas
each other
much (the least
of all 3 states)
2. G, S, G, L, S, G, L, S
Movement
between
molecules
Molecules stay
in fixed position
but vibrate
Molecules can
slip and flow
past each other
Molecules can
easily move
past each other
3. Answers may vary slightly
Heated (word description)
Volume
Shape
Definite volume Definite shape
Definite volume Takes on
shape of
container
No definite
No definite
volume
shape
Heated (picture)
Balloon expands
Cooled (word description)
Cooled (picture)
Balloon shrinks
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.
4. Answers may vary slightly
Heated (word description)
Heated (picture)
Molecules move faster and spread
slightly apart
Cooled (word description)
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Cooled (picture)
8th Grade PSI
Thermal Energy
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.
5. Answers may vary slightly
Heated (word description)
Heated (picture)
Particles vibrate faster and move
slightly apart
Cooled (word description)
Cooled (picture)
Particles vibrate less and are closer
together
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
Saturn
Temperature
(Fahrenheit)
-229
Temperature
(Celsius)
-145
Temperature
(Kelvin)
128
Death Valley
134
56
324
Freezing
32
0
273
Boiling Point
212
100
373
Space
-454.54
-270
2.70
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8th Grade PSI
Thermal Energy
Mars
-81
-63
210
Antarctica
-128
-89
183
Superfluid
Helium
Room
Temperature
Human Body
-455.76
-271
2.17
68
20
293
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
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8th Grade PSI
Thermal Energy
Temperature and KE HW #1
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)
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8th Grade PSI
Thermal Energy
Thermal Energy versus Temperature CW #2
Answer Key
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:
Higher temp
Justification:
Higher temp
Justification:
Same state
Justification:
KE is more, so TE
is more
Thermal Energy
Can not be
determined
2. A: liquid water at 25 C
B: liquid water at 77 F
Kinetic Energy
=
Temperature
=
Potential Energy
=
Justification:
Justification:
Justification:
They actually
have the same
temperature (have
to convert)
They actually
have the same
temperature (have
to convert)
Same
temperature,
same state.
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
Kinetic Energy
Temperature
Potential Energy
Thermal Energy
=
Justification:
=
Justification:
=
Justification:
>
Justification:
Same temperature Same temperature Same temp, same
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8th Grade PSI
There are more
Thermal Energy
state
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
Kinetic Energy
Temperature
Potential Energy
Thermal Energy
<
Justification:
Has a lower
temperature
<
Justification:
Has a lower
temperature
=
Justification:
Same state
<
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 each other (i.e. close together in a solid), then the less
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.
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8th Grade PSI
Thermal Energy
Temperature and Thermal Energy HW #2
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).
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
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8th Grade PSI
Thermal Energy
Methods of Thermal Energy Transfer CW#3
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
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8th Grade PSI
Thermal Energy
Method of Heat
Transfer
Radiation
Conduction
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Description
Describe the animation
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.
Answers may vary some:
 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!
8th Grade PSI
Other examples
Camp fire
Microwave oven
Light bulb
Human body
Thermal Energy
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.
Water boiling
Convection
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Answers may vary some:
 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 denser.
 The cycling of a hot medium rising and a
cold medium sinking creates a convection
current.
8th Grade PSI
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.
Thermal Energy
Hot air balloon
A building (attic is
warmer than a
basement)
Thermal Energy Transfer HW#3
Answer Key
Answers will vary from student to student.
Conductors versus Insulators CW#4
Answer Key
5.
6. Metal foil, cardboard, polystyrene
7.
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8th Grade PSI
Thermal Energy
Specific Heat CW#5
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 HW#4
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 HW#5
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
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8th Grade PSI
Thermal 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 CW#6
Examples of output you should expect to see when your students do this
activity.
Possible SST maps for DURING Rita
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8th Grade PSI
Thermal Energy
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8th Grade PSI
Thermal Energy
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8th Grade PSI
Thermal Energy
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8th Grade PSI
Thermal Energy
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8th Grade PSI
Thermal Energy
Possible SST maps for AFTER
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8th Grade PSI
Thermal Energy
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8th Grade PSI
Thermal Energy
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8th Grade PSI
Thermal Energy
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.
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8th Grade PSI
Thermal Energy