1. Temperature, Heat Transfer & Thermal Energy

2. What is heat?
What is temperature?

3. Thermal Energy, Temperature and Heat Transfer
The terms heat and temperature are often confused by people…
Thermal energy: the TOTAL kinetic energy of the particles that make up a substance
Temperature: the measure of the AVERAGE kinetic energy in an object
Heat transfer: the MOVEMENT of thermal energy from an object of higher temperature to an object of lower temperature

4. Remember…
There is no such thing as “cold” just more heat and less heat
Heat likes to go from high to low until it has nowhere else to go!
We call that EQUILIBRIUM

5. Coffee Pot or the North Sea?
Which is hotter? (temperature)
Which contains more energy? (heat)

6. Iceberg or a glass of water?
Which is hotter? (temperature)
Which contains more energy? (heat)

7. …something which has a higher temperature than another does not necessarily contain more heat energy…
This Photo by Unknown Author is licensed under CC BY-SA-NC

8. Temperature
Temperature is a measure of the average kinetic energy of the particles of a substance.
Fahrenheit, Celsius, and Kelvin are three temperature scales.
Absolute zero (0 K, or –273ºC) is the lowest possible temperature.
Thermal expansion is the increase in volume of a substance due to an increase in temperature.

9. Heat Transfer
The MOVEMENT of thermal energy from an object of higher temperature to an object of lower temperature
Radiation, conduction, and convection are three ways thermal energy is transferred.

10. Radiation The transfer of energy as electromagnetic waves
Does NOT require a medium and CAN occur in a vacuum
Energy moves between molecules
Example: heat radiating from the sun; heat radiating from a lamp or a fire

11. Conduction The transfer of energy through direct contact
Molecules collide & transfer energy
Happens in solids & liquids
Gas molecules are often too far apart for conduction to work well
Example: a spoon placed in hot liquid gets hot itself

12. Convection
The transfer of energy by the movement of a fluid (liquid or gas)
Warmer substances are less dense and cooler substances are more dense
Heated molecules rise and cooler molecules sink
This creates a circular pattern called a convection current
Example: global wind patterns, cooking noodles or soup

13. The three type of heat can occur at the same time!

14. More real-world examples of the three types of heat transfer
This Photo by Unknown Author is licensed under CC BY-SA
This Photo by Unknown Author is licensed under CC BY-SA-NC