1. 4.0 Heat Energy can be transferred in different ways

2. Conduction Is the transfer of energy through CONTACT
Ex. A hot dog roaster that is placed in a fire will heat up rapidly
Why? Heat increases vibration causes particles to bump into one another; increases their kinetic energy as well

3. Conduction
Conductor- a material (usually a metal) that allows heat energy to pass through it easily
Insulator- a material that does not allow heat energy to easily pass through it

4. Discussion:
1. Ken was using a clothes hanger (straightened out) to roast some marshmallows. He almost dropped the hanger half way through as the hanger got too hot. Explain why this happened?
Why do pots have plastic handles and metal bottoms?

5. F.Y.I How does Fire-Walking Work?
Fire walkers walk across red hot coals without getting burnt?? Hypothesize why this can occur?

6. What Happens
The coals have been burning for a long time and are covered in a layer of ash, ash is not a good conductor and does not transfer the heat well
Also the walkers walk across quickly not allowing the heat to build up under their feet

7. Convection
When heat energy is transferred, it does so in a circular pattern called convection currents

8. If a pot is placed on the stove, the water will be heated by conduction, adding kinetic energy
As water heats up, it expands and becomes less dense causing it to rise;
Cooler water sinks to fill this empty space and get heated only to rise again

10. CONVECTION
DEMO:
Three beakers, one hot water, one cold water and one room temperature. Food colouring is added to the hot and cold water
Using a dropper, put some of the cold water into the room temperature beaker and then do the same with the hot water
Exit Slip:
Draw a diagram and record what happens
1. Which drop lasted the longest? Explain this based on the particle theory.

11. Radiation Is the transfer of heat energy in the form of waves
The sun sends out a huge amount of energy waves

12. All hot substances transfer heat waves by radiation
when waves strike another object, they will increase the objects vibration and kinetic energy
This is why an object can feel hot without touching it

13. When heat energy is transferred by radiation, three things can happen:
Absorb heat energy
Reflect the heat energy
Let the energy pass through it