1. Today’s Topic: Heat Transfer

2. There are 3 ways in which heat can be transferred from one object to another:

3. CONDUCTION: the transfer of energy through matter CONDUCTION: the transfer of energy through matter by direct contact of particles. by direct contact of particles. This can happen in solids, liquids and gases. CONVECTION: the transfer of energy because of the CONVECTION: the transfer of energy because of the movement of warm fluids. movement of warm fluids. (Fluids can be liquids or gases) (Fluids can be liquids or gases) This can happen only in liquids and gases - not in solids. RADIATION: the transfer of energy by RADIATION: the transfer of energy by electromagnetic waves. Energy can move by radiation in air like the heat from your electric stove top, or in the vacuum of space the way the Sun heats the Earth. In radiation, the energy does not have to transfer through mass (particles). Heat Transfer

4. Conduction: the “d” means “direct contact” the teapot gets hot because it’s touching the hot burner.

5. Conduction A typical example of conduction would be the heat transferred from hot coffee, through the cup, to the hand holding the cup. A typical example of conduction would be the heat transferred from hot coffee, through the cup, to the hand holding the cup.

6. Convection: the v represents the “v” in movement No fluid moving means no convection!

7. Warm air rises in your house through convection:

8. Radiation Heat transfer by electromagnetic radiation Examples: -anything being warmed by the sun - the heat radiating from a lightbulb, or a person who is warm from exercising

9. All three types of heat transfer:

10. Practice questions: Heat convection occurs in gases and liquids. Heat convection does not occur in solids because solids are unable to — A absorb heat by vibrating B transfer heat by fluid motion C emit radiation by reflecting light D exchange heat by direct contact

11. Practice Questions: In which container is the substance unable to transfer heat by convection? 

12. The moon’s surface becomes hot during the long lunar day because the sun transfers heat to the moon. This heat transfer is accomplished almost entirely through the process of — F convection G refraction H conduction J radiation

13. A man who was sleeping wakes up because he hears the smoke alarm go off in his house. Before opening the bedroom door, the man feels the door to see whether it is warm. He is assuming that heat would be transferred through the door by — A conduction B convection C radiation D compression

14. The transfer of heat by the movement of air currents in Earth’s atmosphere is an example of — A conduction B convection C radiation D fusion