4.7 Entrance Activity 1

1. What is the most common heat transfer mechanism in solids?
-> Radiation
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 (heat from sun -> space (vacuum) -> Earth)
4. Why can't conduction happen in a vacuum?
-> Because there is no matter in a vacuum, therefore energy cannot be transferred through contact of particles (conduction)
5. What happens to the space between the molecules in a gas when you heat it?
-> It increases, the molecules vibrate more violently and move further apart
6. What happens to the density of a gas when you heat it?
-> It decreases, as density is the measure of molecules within a certain area (this is also responsible for convection currents)
7. Why can't convection happen in a solid?
-> Because the particles are so closely packed together, that by the time there is enough energy in the system to cause the molecules to vibrate violently enough to form the high density/low density areas responsible for convection - it would already have turned into a liquid state.