Heat Transfer

1. Heat Transfer EQ: What are three ways heat is transferred?

2. __________________ • the transfer of thermal energy through matter from particle to particle as they touch.

3. Conduction • the transfer of thermal energy through matter from particle to particle as they touch.

4. A spoon in a cup of hot soup becomes warmer because the heat from the soup is conducted along the spoon. Conduction is most effective in solids-but it can happen in fluids (liquids and gases).

5. ____________________ * the transfer of thermal energy by the movement of a gas or liquid. The circular motion caused by density differences that result from temperature differences are called convection currents.

6. Convection Convection is the transfer of thermal energy by the movement of a gas or liquid. The circular motion caused by density differences that result from temperature differences are called convection currents.

7. Convection Currents at Work

8. Convection Currents at Work Heat pumps pump cold air out in the winter and warm air out in the summer.

9. _____________________ *the transfer of thermal energy by electromagnetic waves such as visible light and infrared waves. (See p. 636-637). This energy can be transferred through particles of matter OR empty space! Energy from the sun is an example of radiation.

10. Radiation Radiation is the transfer of thermal energy by electromagnetic waves such as visible light and infrared waves. (See p. 636-637). This energy can be transferred through particles of matter OR empty space! Energy from the sun is an example of radiation.

11. Some energy from the sun is absorbed by Earth and some is radiated back out into space.

12. Review

13. Review conduction convection radiation

14. Review

15. Review conduction convection radiation

18. How does heat move? Heat moves from the ____________ object to the _____________ object.

19. How does heat move? Heat moves from the warmer object to the cooler object.

20. What happens to the temperature of two objects as heat is transferred from one to the other? The hotter object becomes ________ while the cooler object becomes ________ until both objects are the same temperature. They are said to reach equilibrium. Hot water at 70 degrees Cool water at 30 degrees What will be the new temperature?

21. What happens to the temperature of two objects as heat is transferred from one to the other? The hotter object becomes coolerwhile the cooler object becomes hotteruntil both objects are the same temperature. They are said to reach equilibrium. Hot water at 70 degrees Cool water at 30 degrees What will be the new temperature?

22. What happens to the temperature of two objects as heat is transferred from one to the other? If there are equal amounts of water in the two cups, add their temperatures and divide by 2. (70 + 30) / 2 = 50 Hot water at 70 degrees Cool water at 30 degrees What will be the new temperature?

23. True or False? Everything has thermal energy. Therefore, even ice has heat. Answer: ____________ Why: ______________________________ ___________________________________

24. True or False? Everything has thermal energy. Therefore, even ice has heat. Answer: True! Why: All objects have moving particles that have thermal energy

25. True or False? A swimming pool has more thermal energy than a pot of hot coffee. Answer: ___________________ Why: _____________________________ __________________________________

26. True or False? A swimming pool has more thermal energy than a pot of hot coffee. Answer: True Why: A swimming pool has many more particles than a pot of coffee—each with energy (Thermal energy = TOTAL energy)

27. 1. What happens to the movement of the molecules as a substance is heated? 2. How does this affect the size or shape of the object? Answer 1: __________________________ Answer 2: _________________________

28. 1. What happens to the movement of the molecules as a substance is heated? 2. How does this affect the size or shape of the object? Answer 1: the molecules move faster Answer 2: the object expands in size

29. When the air molecules in the balloon are heated and move faster, they become less __________ and lift the balloon off the ground.

30. When the air molecules in the balloon are heated and move faster, they become less dense and lift the balloon off the ground.

31. Why do some objects feel cold to the touch while others feel warm? Answer: ____________________________ ___________________________________

32. Why do some objects feel cold to the touch while others feel warm? Answer: Objects may FEEL cold because heat is conducted quickly away from the body (conductors) or they may FEEL warm because heat is conducted slowly away from the body (insulators).

33. How do insulators keep a person warm? Answer: ____________________________ ___________________________________ Layers trap air!

34. How do insulators keep a person warm? Answer: They prevent body heat from escaping. Layers trap air!

35. Air is a poor conductor. Therefore, it is a good insulator.

36. Review Game Click here to review what you have learned. Number your paper 1-20 and see how you do. Good luck!