Conduction, convection and radiation from Collins textbook

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Answers to Entrance Activity for 4.7

Answers to
Entrance Activity for 4.7
Answers...
1. What is the most common heat transfer mechanism in solids?

Conduction
2. What is the most common heat transfer mechanism in liquids and gases?

Convection
3. What is the only heat transfer mechanism in a vacuum?

(Infra-red) Radiation
4. Why can't conduction happen in a vacuum?

There are no particles in a vacuum to transfer the vibrations
5. What happens to the space between the particles in a gas when you heat it?

The space between the particles increases
6. What happens to the density of a gas when you heat it?

It decreases because the space between the particles increases
7. Why can't convection happen in a solid?

In a solid the particles are fixed in position and are not free to move

4.6

4.6 recall that energy transfer may take place by conduction, convection and radiation

Task 1 Try the animation: particle model - conduction
Extension: what is the limitation of this animation? (Check your answer with the Heating a Solid animation)
The animation does not show that in addition to the vibration of the particles, the block of metal is supposed to expand.

Task 2
Try the quiz on the Cooking animation
Extension: what's the mistake in the description of convection?
The mistake is that the particles aren't supposed to shrink and sink just because they were cooled down.

Particle model - conduction.swf Download this file

Cooking using Conduction, Convection and Radiation - interactive animation.swf Download this file