1. Environmental Science
Heat Transfer
Environmental Science

2. Heat Transfer Heat always moves from a warmer place to a cooler place
Example: If you put a hot cup of coffee into the refrigerator, heat energy from the coffee will travel to the refrigerator.
Heat transfer
warmer
cooler

3. Methods of Heat Transfer
There are THREE methods of heat transfer
CONDUCTION
CONVECTION
RADIATION

4. Conduction A transfer of heat through direct contact
On a molecular level, warmer molecules are vibrating faster than cooler ones.
When they come in contact, the faster moving molecules “bump into” the slower moving ones and heat is transferred.

5. Conduction Examples
The heat from a hot liquid makes the cup itself hot.
An ice cube will soon melt if you hold it in your hand. The heat is being conducted from your hand into the ice cube.
After a car is turned on, the engine becomes hot. The hood will become warm as heat is conducted from the engine to the hood.
A metal spoon becomes hot from the boiling water inside the pot.

6. Convection Travels through fluids Creates convection currents
warmer / less dense materials rise, cooler / denser materials sink

7. Convection Examples
Hot air balloon – heated air moves upward, causing the balloon to rise. The pilot releases some of the hot air and cool air takes it place, causing the balloon to lower.
Boiling water - The heat passes from the burner into the pot, heating the water at the bottom. Then, this hot water rises and cooler water moves down to replace it, causing a circular motion.

8. Radiation
Heat energy that travels as an electromagnetic wave (no medium)
This is how heat from the sun reaches Earth

9. Solar Radiation

10. Heating of the Ocean Heat from the sun is ABSORBED by the ocean
This heat is then transferred by OCEAN CURRENTS