1. Thermal Energy Conversions Conduction - Convection - Radiation

2. Energy Terminology Absorbers - take in the energy
Examples: Dark objects like black t-shirts
and roof tops
Reflectors - reflect the energy
Examples: Shiny materials, mirrors, and aluminum foil

3. Conduction Transfer of thermal energy by direct contact
Always from a solid hot object to a solid cold object
Takes place in solid, liquid or gases
Example: A metal spoon inside a saucepan gets hot while a saucepan is getting heated.
If you were the chef in this picture and had to stir the contents for 20 minutes non-stop while on high heat – which type of spoon
would you want to use?

4. Conduction - Continued
In order for conduction to occur, there has to be a conductor.
Conductors transfer heat easily
The more tightly packed the particles of the conductor, the better it is
Most often Metals-metal spoon, metal pan, copper, iron, steel, silver

5. Conduction - Continued
The opposite of a conductor is an insulator.
Does NOT allow heat to move easily through
Most often wood, plastic, glass, fiberglass, air, Styrofoam, and double pane windows that is air between 2 panes of glass
R-value - rates insulation for houses
higher number the better
R R R-20

6. Convection Transfer of thermal energy in fluids – anything that flows
Always between liquids and gases
Example: hot air balloon, wind, ocean & air currents, home heating, all the soup in a pot becoming warm
warmer fluids (less dense) rise, buoyant convection
cooler fluids (more dense) sink
wearing sweater keeps the heat from being taken away
from the body

7. Radiation Transfer of thermal energy through waves.
Electromagnetic waves-light, ultraviolet rays, x-rays,
infrared rays
Travels though gas and no air (vacuum) (outer space)
Colors reflect waves differently.
Black absorbs, White reflects
Example: sun’s energy, microwaves and radio waves infrared light bulbs, person warmed by a fire.