1. Heat Transfer

2. Energy & Temperature Molecules are constantly moving
Faster movement = more energy
Thermal energy = total energy of motion in molecules of a substance
Temperature = average amount of energy of motion of each molecule

3. Measuring Temperature
Thermometer = used to measure temperature
Works because liquids expand when heated and contract when cooled
Units = degrees
Water Freezes: 0°C and 32°F
Water Boils: 100°C and 212°F

4. How Heat is Transferred
Heat = energy transferred from hotter to colder object
Three types:
Radiation
Conduction
Convection

5. It is the direct transfer of energy by electromagnetic waves
Radiation
It is the direct transfer of energy by electromagnetic waves
Example: feel the sun or heat from a campfire

6. Conduction
It is the transfer of energy between substances that are touching
The closer the molecules in a substance, the more effectively they can conduct heat
Conductors = conduct heat well
Insulators = do not conduct heat well

7. Convection It is the transfer of heat by the movement of a fluid
Gases and liquids are fluids
Molecules in gases and liquids can move from place to place and take their heat with them

8. Heat Transfer in the Troposphere
Only first few meters heated by conduction because air does not conduct heat well
Convection causes most of heating of troposphere
Warm air = less dense = rises up
Cooler air = more dense = sinks down
Convection currents formed by rising and sinking of air