1. Heat –Thermal Energy moving from a warm object to a cooler object Heat can transfer or move in 3 ways –Conduction –Convection –Radiation

2. Conduction Heat transferred from one molecule to another without the object moving itself Always from Warmer to Cooler Usually Requires Contact

3. Heat is transferred by the mass movement of molecules from one place to another Occurs within a Liquid or Gas Convection

4. A circulation gets established called Convection Currents Warm, less dense water at bottom rises and is replaced with cooler, more dense water from above

5. Radiation Conduction and Convection require a medium, like metal and water, to transfer heat from a hot region to a cold region Radiation transfers heat through a gas or a vacuum: –Heat from the Sun –Heat from surface of a hot object

6. Wave is transfer of Energy by vibration Radiation is the transfer of Energy by a special type of wave called an Electromagnetic Wave There are many types of EM waves and many applications: –Infrared we sense as Heat –Visible light we sense as color –X-Rays –Radio & TV –Cell Phone –All Wireless devices Electromagnetic (EM) Waves

7. Conduction, Convection, and Radiation often occur together

8. Thermal Expansion & Contraction As the thermal energy of a substance increases, its molecules vibrate faster, spread out and the substance expands As the thermal energy of a substance decreases, its molecules vibrate slower, get closer and the substance shrinks Matter expands when heated Matter contracts when cooled

9. Interesting Demos on Conduction Convection Radiation