Entrance Activity for 4.7

Conduction, Convection and Radiation

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? Radiation

4.             

Why can't conduction happen in a vacuum? Because conduction happened by the vibration of molecules which bump into each other and are passed through the bonds from particle to particle. There are no molecules in a vacuum.

5.             

What happens to the space between the molecules in a gas when you heat it? The space between the molecules increases (without the molecules itself increasing).

6.             

What happens to the density of a gas when you heat it? Density decreases.

7.             

Why can't convection happen in a solid? Because for convection to happen molecules must flow to create convection cycle. However, the molecules are packed together in solid and do not flow. (The particles' movement is restricted.)