Thermal Energy Transfer

1. Thermal Energy Transfer

2. Thermal Energy Transfer • Thermal Energy can be transferred by three methods • Conduction • Convection • Radiation

3. Conduction • Conduction is the transfer of thermal energy by contact between particles of matter from a high temperature to a low temperature • Heat moves faster through solids and liquids • This is because the particles are closer together

5. Convection • Convection is the transfer of thermal energy by the partcles of a fluid • Fluids are liquids and gases • Currents transfer heat from high temperature to low temperature • As a fluid heats up it expands and becomes less dense • This heated fluid will then rise above fluid of a lower temperature

7. Radiation • Radiation is the transfer of energy by electromagnetic waves • It can travel through space where there is no matter • This is radiant energy

8. Radiation • Materials can absorb, reflect, or transmit radiation • Dark colors absorb radiation • Light colors reflect radiation

10. Radiation can pass through the particles that make up solids liquids and gases

12. Insulators • An insulator is a substance that heat flows slowly through • They will have a high specific heat • Gases make good insulators because they do not conduct heat well

14. THermodynamics

15. Using Heat • On of the most basic ways of using heat is to heat your home • Most homes used a forced air system that pumps warm air into a room and heat the room by convection

16. Radiators • Older buildings may use radiators • A radiator uses steam to heat rooms by convection

17. Thermodynamics • You can increase the thermal energy of an object with out adding heat • Thermodynamics is the study of the relationship between thermal energy, heat, and work

18. 1st Law of Thermodynamics • The increase in thermal energy of a system equals the work done on the system plus the heat transferred to the system

19. 2nd Law of Thermodynamics • It is impossible for heat to flow from a cool object to a warmer object unless work is done. • If you hold ice in your hand, heat flows from you to the ice cube

20. Engines • Heat can be converted into work • A heat engine is a device that turns heat into work • It is impossible to make an engine that completely converts heat into work • This is because it will violate the second law of thermodynamics