1. Thermal Radiation

2. Particles bump into nearby particles and make them vibrate more.
or conduction?
Convection
Conduction
Particles bump into nearby particles and make them vibrate more.

3. or conduction? Convection Convection
Particles with a lot of thermal energy in a liquid or gas move, and take the place of particles with less thermal energy.

4. Happens in liquids and gases only.
or conduction?
Convection
Convection
Happens in liquids and gases only.

5. or conduction?
Convection
Conduction
Happens in solids only.

6. Discuss what these pictures may be showing.

7. How else can thermal energy move?
All objects transfer thermal energy by infrared radiation.
The hotter an object is, the more infrared radiation it gives off.

8. Radiation
No particles are involved in radiation, unlike conduction and convection.
This means that thermal energy transfer by radiation can even work in space, but conduction and convection cannot.

9. Practical
We are going to do an experiment to see how heat (thermal energy) escapes by radiation from two flasks.
One flask is covered in black paper the other is covered in silver foil.
Which do you think will radiate the most heat?

10. Which flask cooled down faster?
Dark surfaces emit more thermal radiation than shiny surfaces.
They also absorb more thermal radiation.

11. Uses of radiation
Radiation is how we can feel the heat of the Sun, even though it is millions of miles away in space.
Infrared cameras give images even in the dark, because they are detecting heat, not visible light.