E3: Electrical energy — E level

Physicists and engineers use the words “energy” and “power” in a very specific way.

Energy: The amount of work that can be done. Measured in Joules, shortened to J. It’s also measured in kWh – kilowatt-hours – for electricity.

Power: How fast the work is getting done. Measured in Watts, shortened to W.

You can think of energy as the amount of water in a water tank. Power is like how fast the water comes out of the tank through a tap.

2.5kW (2,500W) when cooling. 3.2kW (3,200W) when heating. Cools or heats a whole room.

1,000W to keep warm if you’re close to it.

20W at maximum loudness. Good for a small party.

5W to talk to someone a few kilometres away.

11W for a very bright bulb.

1,000W on one hotplate and 1,400W on the other hotplate. About as powerful as it gets.