1. Thermal Energy Chapter 14

2. Key Ideas  What does temperature have to do with energy?  What makes things feel hot or cold?  What affects the rate that thermal energy is absorbed or emitted?  When is thermal equilibrium reached?  How does energy transfer happen?

3. Temperature and Energy Temperature: a measure of the average kinetic energy of the particles in an object. All particles have kinetic energy. All particles in a substance are constantly moving. As the average kinetic energy of the particles in an object increases, the object ’ s temperature increases.

4. Why do some objects feel hot while other objects feel cold? The feeling associated with temperature difference results from energy transfer. Temperature and Energy

5. Heat: the energy transferred between objects that are at different temperatures. Temperature changes indicate an energy transfer. The transfer of heat always moves from an area of higher temperature to an area of lower temperature. The greater the difference in the temperatures of the two objects, the faster heat is transferred. Temperature and Energy

6. Heat energy can be transferred in three ways: conduction convection radiation Temperature and Energy

7. Radiation: movement of energy through space in the form of ultraviolet, visible light and infrared rays.  The sun warming your face  All hot objects give off infrared radiation Temperature and Energy

8. Conduction: the transfer of heat by physical contact.  Air molecules contacting a hot object. Temperature and Energy

9. ConvectionConvection: the cycle of warm air rising and cool air falling. Temperature and Energy

10. Thermal Conductivity: Depends on the rate at which thermal energy is transferred from one end of the material to another. Thermal conductors: have a high rate of thermal energy transfer. Thermal insulators: have a slow rate of thermal energy transfer. Temperature and Energy

11. Objects are continually absorbing and emitting thermal radiation. The rate at which thermal radiation is absorbed or emitted depends on: Temperature Color Texture Exposed surface area Temperature and Energy

12. If an object absorbs more thermal energy than it emits (no phase change), the temperature will increase. If the object emits more thermal energy than it absorbs (no phase change), the temperature will decrease. Temperature and Energy

13. Thermal equilibrium: The amount of thermal energy absorbed is equal to the amount of thermal energy emitted. As a result, the temperature remains constant. Temperature and Energy

14. Conduction and Convection Temperature and Energy