Transfer of thermal energy

Question 1

Conduction ( molecular vibration )

Answer 1

-When heat is applied
-the particles vibrate faster
-collide with less energetic neighbours
-transfer some energy to them
-neighbouring particles gain energy

Question 2

Conduction (electron diffusion)

Answer 2

-When heat is applied
-free electrons in metals move faster and diffuse to cooler parts
-electrons transfer their energy to the molecules
-molecules gain energy

Question 3

Convection

Answer 3

Occurs mainly in liquid and gases
The water molecules near the heating element would expand become less dense and rise. The cooler and denser water molecules at the top would sink. This sets up a convection current that allow thermal energy to be transferred throughout the water

Question 4

Radiation

Answer 4

• The transfer of heat energy in form of electromagnetic waves
• Radiation can pass through vacuum
• Dull, black surfaces are the best absorbers and emitters of radiation
• Shiny metal surfaces are the worst emitters and absorbers of radiation