1.7 - Energy transfer by design

Question 1

What is the relationship between the temperature difference between an object and its surroundings and the rate of energy transfer?

Answer 1

The greater the temperature difference between an object and its surroundings, the greater the rate at which energy is transferred

Question 2

What four main things does the rate at which energy is transferred depend on?

Answer 2

• The temperature difference between an object and its surroundings
• The materials the object is in contact with
• The shape of the object
• The surface area of the object

Question 3

Why do we sometimes want to maximise the rate of energy transfer through conduction, convection and radiation?

Answer 3

To keep things cool

Question 4

Why do we sometimes want to minimise the rate of energy transfer through conduction, convection and radiation?

Answer 4

To keep things warm

Question 5

How can we maximise the rate of energy transfer through conduction, convection and radiation? (3)

Answer 5

Use things that:

• are good conductors
• are painted dull black
• have the air flow around them maximised

Question 6

How can we minimise the rate of energy transfer through conduction, convection and radiation? (3)

Answer 6

Use things that:

• are good insulators
• are white and shiny
• prevent convection currents by trapping air in small pockets