Heat Transfer

Question 1

what affects the rate of heat transfer?

Answer 1

Surface area, Volume and the Material

Question 2

what are the features of an insulated bottle?

Answer 2

1. Outer cap/cup
2. Plastic cap filled with cork
3. Shiny mirrored surfaces
4. Vacuum
5. Sponge
6. Plastic case

Question 3

describe how the features in an insulated bottle works

Answer 3

1. The bottle is double wall insulated with a vacuum between the two walls. This stops all conduction and convection through the sides
2. The walls either side of the vacuum are silvered to keep heat loss by radiation to a minimum
3. The bottle is supported by insulating foam. This minimises heat conduction to or from the outer glass bottle
4. The stopper is made of plastic and filled with cork or foam to reduce any heat conduction through it

Question 4

how does the human body control heat transfer?

Answer 4

In the cold the hairs on your skin ‘stand up’ to trap a thin layer of insulating air around the body. This limits the amount of heat loss by convection. However when you are warm your body diverts more blood flow near the surface so that more heat can be lost by radiation

Question 5

how do animals control heat transfer?

Answer 5

Through fur and ear size