Science·Energy·conceptual
Power: watts and energy per second
Define power as the rate of energy transfer (power = energy ÷ time, measured in watts), and compare energy transfer rates in different everyday contexts
Suggested ages 12–13
Evidence of understanding
- States the definition of power and gives its unit (watt)
- Uses P = E/t to calculate power, energy, or time given the other two quantities
- Compares the power ratings of common appliances and explains what the rating means
- Explains why a higher-powered device does the same job faster but uses more energy
Assessment prompt
If Power: watts and energy per second was comparing a 100 W light bulb with a 10 W LED, could they explain what those numbers mean and calculate how much energy each uses in an hour?
Standards alignment
KS3.Sci.Phys.Energy.4GB · uk-nc-2013
Power and Energy Transfer
The national curriculum in England: Key stages 1 and 2 framework document · KS3