1. Heat Notes  Expansion – to increase in size  Contraction – to decrease in size  Most materials expand when heated and contract when cooled –Exceptions: water expands when it freezes, certain plastics

2. Heat Notes  Materials expand because heat increases kinetic energy. The atoms and molecules bounce around more, knocking each other farther apart. –Example: A thermometer works because alcohol expands when it is heated causing it to rise higher in the thermometer when it is hot.

3. Heat Notes - Energy  Energy is the ability to do work  Energy can change forms. All energy can change into heat.  Potential energy – energy due to an object’s position  Kinetic energy – energy of motion

4. Heat Notes - Temperature  All matter is made up of atoms that are in motion.  Temperature - average kinetic energy of an object  Thermometer – measures temperature ( O C Celsius)

5. Heat Notes  Heat – amount of thermal energy transferred from one object to another  Heat moves from hot to cold  Calorimeter – used to measure heat

6. Heat Notes – Heat Transfer  Three ways to transfer heat: –Convection –Radiation –Conduction

7. Heat Notes – Convection  Transfer of heat through a fluid (liquid or gas) due to the fact that hot air is less dense than cool air –Hot air rises, spreads out, cools off and sinks –Examples: water boiling, currents in the mantle of the Earth, air in a room

8. Heat Notes - Radiation  Transfer of heat in waves such as light –Colors that absorb radiation = dark (black) –Colors that do not absorb radiation = light (white)

9. Heat Notes - Conduction  Transfer of heat through direct contact –Heat is transferred easily by a conductor –Heat is transferred poorly by an insulator

10. Heat Notes - Conduction  Insulate – a material that does not conduct heat well –Examples: feathers, hair, clothes, wool, paper, snow, blubber, skin, blanket, fiberglass, wood, straw, air

11. Heat Notes - Conduction  Conduct – a substance through which electrons move freely, transmitting heat or electricity –Examples: Metals (Copper, silver, steel, brass, aluminum)