Radiation and Insulation

Question 1

thermal energy transfer by conduction

Answer 1

heat transfers through direct contact as fast moving particles transfer energy to slower moving ones.

Question 2

thermal energy transfer by convection

Answer 2

heat moves through (liquid or gas) as warm less dense air rises and cooler denser air sinks.

Question 3

thermal energy transfer by radiation

Answer 3

heat transfers through electromagnetic infra-red waves, without needing a medium or particles.

Question 4

surface and temperature (emission)

Answer 4

dark surfaces emit more radiation than light surfaces. The hotter the object is the more radiation it emits.

Question 5

surface and temperature (absorption)

Answer 5

dark surfaces absorb more radiation than light surfaces. Hotter objects absorb more radiation.

Question 6

ways of reducing unwanted energy transfer

Answer 6

• use insulation materials (foam, cloth) to trap air
• seal gaps so that nothing is able to enter or leave
• low pressure air around to stop heat.

Question 7

radiation

Answer 7

energy that moves from one place to another in a form that can be described as waves or particles