1. Conduction Investigation 4, Part 2
Heat Transfer
Conduction
Investigation 4, Part 2
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2. ESSENTIAL QUESTIONS
* I can explain how radiant energy from the Sun heats solid and liquid materials.
* I can describe how heat transfers through multiple materials.
I can describe how the atmosphere heated.
I can determine how to conduct a fair experiment.

3. In Your Notebook… Answer the following questions:
What is radiant energy?
2. How does radiation affect the surface of Earth?
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4. In Your Notebook… Answer the following questions:
What is radiant energy?
Energy that passes through space
2. How does radiation affect the surface of Earth?
Earth receives energy from the Sun
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5. Visible Light
Is the main kind of energy from the Sun that heats the Earth
Energy is transferred when light energy is absorbed by molecules in Earth’s surface, causing them to move faster, which increases the temperature!
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6. Heat Transfer Walking barefoot on a hot day - What did you feel? Why?
How did heat transfer from the cement to your feet?
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7. Energy Transfer Challenge
Heat cold water to about 30˚C without mixing the hot and cold water.
Using these materials:
Cold water
Hot “Salt” water
Cup
Vial
Thermometer
How would you set up the experiment?
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8. Hot Water Setup Material Person: Get a vial, cup, and 2 thermometers
Fill the vial with cold water
Fill the cup half full with hot salt water
Measure and record temp of BOTH water samples
Now, warm the cold water to 30 ◦ C without mixing it with the red (salt) water
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9. The Results
Were you able to raise the temperature of the cold water to 30˚C?
How did heat transfer from the hot to cold water?
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10. The Explanation No cold, only heat Cold is actually low levels of heat
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Heat energy goes out of your hand into the ice cube

11. Heat Motion of atoms and molecules Greater motion = more heat energy
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12. Conduction
Energy transfer happens between molecules or atoms when they come in contact
Faster moving molecules in the hand bump into the slower moving molecules in the ice
Molecules in hand slow down and we feel it as cold
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13. Multimedia Watch the animation of solids, liquids, and gases.
Watch the animation on conduction.
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CD-ROM Molecules in Solids, Liquids,and Gases ( Matter and Energy section).

14. Heat Transfer Diagram/ Ticket Out the Door
How could you show the energy transfers as a flow chart from the hot water to the alcohol in the thermometer?
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15. On Monday, we will explore conduction through materials
BREAKPOINT
On Monday, we will explore conduction through materials
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Student Lab Notebooks P. 17

16. Heat Conduction Responses
Complete the “Heat Conduction” worksheet on page 17 of your lab book.
BREAKPOINT
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Student Lab Notebooks P. 17

17. Review
Remember: when two materials at different temperatures make contact, energy transfers from the hotter material to the colder material.
As materials gain heat energy, the motion of their atoms and molecules increases.
Molecular Motion = Heat
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18. Multimedia Show thermometer animation.
Draw the energy transfer going on in the animation.
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CD-ROM Thermometer Animation ( Matter and Energy section)

19. Pot of Soup Metal spoon that was in a pot of cooking soup?
Surprised to find that it was really hot.
How did the spoon handle get so hot?
Spoon handle hadn’t been in the soup
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20. Conduction?
Can heat conduct through an object?
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21. Conduction Experiment
Materials
Aluminum and steel bars
Temperature strips
Plastic-foam cups
Large plastic cups
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22. Temperature Strips Liquid-crystal temperature strips
Crystals inside turn colors when they reach a given temperature
Different crystals produce their colors at different temperatures
No color if temperature is below 30˚C or above 36˚C
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23. Conduction Through Materials
“Conduction through Materials” worksheet
Use the materials to complete the Observations and Conclusion section
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Student Lab Notebooks P. 19

24. The Results
1. The temperature strips displayed color after the metal had been in the hot water for awhile. Color indicates the temperature went up
Heat energy(molecular motion) in hot water molecules transferred to metal molecules, making them move more. Heat energy (motion) moved through the metal by energy transfer from molecule to molecule in the metal
Both metals conduct heat, Aluminum conducts better, heat moved up the bar faster.
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Student Lab Notebooks P. 19

25. How do you think….
The Sun shines on Earth and the air gets warm. How do you think that happens?
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Student Lab Notebooks P. 19

26. How it happens…. Conduction Radiation
Radiant energy strikes Earth’s surface
Conduction
Radiation
Surface molecules increase their motion
Molecules of air touches the heated surface of Earth
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The surface absorbs the energy
Energy is transferred from surface to the air

27. Another energy transfer
Even more important way that heat energy enters the atmosphere
Reradiation
Another way heat energy enters the atmosphere
Matter radiates heat and distributes it into the atmosphere
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28. Reradiation All matter radiates energy
Hot matter radiates more energy than cold
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29. Reradiation
Sand, soil, water & air absorb energy from the Sun - they warmed up
When moved to shade they cooled down
Newspaper
Soil
Sand
Water
Air
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Reradiated the energy that was absorbed to the air

30. What happens to the reradiated energy?
Most reradiated energy is not visible, it is infrared (heat) C O
Infrared energy
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Then transfers the energy to N2 and O2 in the atmosphere

31. To review… Earth ‘s atmosphere can be heated 3 ways 1
To review… Earth ‘s atmosphere can be heated 3 ways 1. The atmosphere can absorb radiation directly from the sun 2. Air molecules gain energy when they come in contact with Earth’s surface (conduction) 3. Earth’s surface reradiates energy. Air molecules (water and carbon dioxide) absorb radiant energy.

32. Conductor: a substance that allows heat to travel through it easily Insulator: a substance that prevents heat from traveling through it easily

33. Reading Read “Heating the Atmosphere” starting on page 22.
With a partner answer the “Think Questions” on page 26.
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Student Resource Book P.22-26