1. Convection in Water Investigation 5, Part 2
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2. How heat is transferred….
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

3. Heat in solids Molecules are locked together
Molecules begin to vibrate, continues through the rest of the molecules creating heat
Absorbs radiant energy
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4. Heat in fluids (liquids and gases)
Molecules are not locked into position
Move around freely
Heat is transferred by one molecule touching another
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5. Challenge of the Day
Make layers of plain water that are different temperatures.
Predict and record the colors of the layers on page 27 of your lab book.
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Student Lab Notebook P.27

6. Materials 3 vials (two with caps)
2 plastic-foam cups (to insulate cold and hot water)
2 pipettes
1 plastic cup
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Student Lab Notebook P.27

7. Procedure red, blue, and clear Fill a vial
Create three layers in the vial
red, blue, and clear
3/4 full
Room Temperature Water
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Student Lab Notebook P.27

8. Do not bump or jostle an experiment in progress
Warning!!!!!
Do not bump or jostle an experiment in progress
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Student Lab Notebook P.27

9. How to successfully layer
Wait for water to stop moving
Room Temperature Water
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Student Lab Notebook P.27

10. How to successfully layer
Wait for water to stop moving
Carefully introduce the blue water under the room temperature water
Room Temperature Water
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Student Lab Notebook P.27

11. How to successfully layer
Wait for water to stop moving
Carefully introduce the blue water under the room temperature water
Room Temperature Water
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Student Lab Notebook P.27
Carefully introduce the red water on top of the room temperature water

12. Layered vial Stand for 5 minutes
Discuss with your partner what is happening
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Student Lab Notebook P.27

13. Observations
What happened in your vial after is sat undisturbed for a few minutes?
The red water starts to sink to the bottom of the vial
What do you think caused the red water to start to descend?
The warm red water cooled
Increasing the density of the red water
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Student Lab Notebook P.27

14. Why? Hot red water layered on top of the room temp water?
Cold blue water layered under the room temp water?
Less Dense
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Student Lab Notebook P.27
Denser

15. Heating the Layered Vial
Create the 3 layered vial
Put 1 cm of hot water in a plastic cup
Place the layered vial carefully in the cup of hot water and observe.
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Student Lab Notebook P.27

16. Heating the Layered Vial
What did you observe?
How can you explain your observations?
Can you explain the energy transfer that happened?
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Student Lab Notebook P.27

17. Molecular model Water becomes less dense as its temperature increases!
As heat is absorbed by water, the molecules move faster and bang into each other with greater force and frequency. This drives the molecules farther apart. When molecules are forced farther apart, the water becomes less dense.
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Student Lab Notebook P.27

18. Convection
When a mass of fluid is warmer or colder than the surrounding fluid, the mass will rise or sink in the surrounding fluid.
This motion of masses is called convection!
This is the third way heat transfers.
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Student Lab Notebook P.27

19. Convection
The motion of masses or streams of fluid, due to difference in density resulting from temperature.
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Student Lab Notebook P.27

20. Reading “Convection” on pages 32-33 TG- p.168
Student Resource Book P.32-22