1. TOPIC: Heat AIM: How is heat transferred?

2. Movement of heat from warm  cool object
What is
heat
transfer?
Movement of heat from warm  cool object
Example = hot pan
Heat moves from pan  handle

3. 3 types of heat transfer

4. Heat transfer in SOLIDS1.
Conduction
Heat transfer in SOLIDS

5. Heat transfer by the direct contact of molecules

6. Fast moving molecules (have more heat)  Bump into slower ones  Start to move faster  collide with other slower molecules…

7. Why can the girl on the right toast marshmallows without getting burned?

8. Conductor
Material that allows heat to move through it easily
Metals (copper & silver are the best)

9. Example: copper pipes
(Heat exchangers in hot water tanks, under floor heating systems, and car radiators)

10. TOPIC: Heat AIM: How is heat transferred? Cont’d…

11. Do not conduct heat easily
Insulators
Do not conduct heat easily
Wood, paper, wax, air, house insulation, plastic

13. Transfer of heat in liquids & gases
Liquid heated  molecules move faster & farther apart
less dense  rise carrying heat with it 2.
Convection

14. Example: warm air rises, cool air sinks

15. Up & down movement of molecules due to changes in density
Convection
currents
Up & down movement of molecules due to changes in density

17. Convection Currents Inside the Earth

20. 3.
Radiation
Heat transfer through space
Can travel when no matter is present (vacuum)
Heat energy from sun, stars, fire

21. Radiation from the Sun travels through empty space.

23. Radiation from the fire heats the marshmallow.

24. SOLIDS
LIQUIDS & GASES
THROUGH SPACE

26. REVIEW C
conduction B
convection A
radiation

27. REVIEW A
convection B
radiation
conduction D C
convection

28. http://player. discoveryeducation. com/index. cfm