Reducing Energy Transfers
Science: KS3, topic 3.1.10
Reducing Unwanted Energy Transfer
We take steps to reduce the amount of energy wasted.
Lubrication
- Lubrication reduces frictional forces.
- A moving object normally has at least one frictional force acting against it.
- The frictional force causes some energy to be lost.
Reducing Friction
- Lubricants can reduce the friction between the surfaces of objects that are rubbing together.
- Lubricants are normally liquids.
Thermal insulation
- Heat will be lost through the roof, windows, walls and floor.
Reducing Energy Transfer
- To reduce the energy transfer, we might:
- Fit loft insulation (the roof).
- Use double glazing (windows).
- Use cavity wall insulation (walls).
- Fit carpets (floors).
Walls in homes
- We can decrease the rate a house cools down by:
- Having thicker walls.
- Having walls made from a material with a lower thermal conductivity.
Thermal Conductivity
- A material with a higher thermal conductivity conducts more heat.
- A higher thermal conductivity means a higher rate of energy transfer by conduction.
Test yourself on Reducing Energy Transfers
Which of these reduces energy lost through walls in homes?
Two walls have the same thickness. Wall A is made from a material with high thermal conductivity. Wall B is made from a material with low thermal conductivity. Which wall loses heat faster?
Which statement is true?