Students actually measure energy use with a Kill-a-Watt meter.

Concrete activity that helps student relate their everyday experiences to the discussion of climate change.

Energy data is from 2009.

Comment from expert scientist: Activity needs a better primer or the difference between power and energy needs to be taught before the exercise since most people do not know the difference. It could be explained as follows: The scientific definition of power is simply the rate of energy use, that is power is equal to energy per time. Many people confuse power with energy. Knowing a particular machine's power rating tells you nothing about how much energy it will use unless you know for how long it will run. The unit of energy is the joule (J) which is the force of one Newton acting over the distance of one meter.

As power is simply the energy flow per unit time, it is measured in watts; one watt is equal to one joule per second. One watt is also the force of one Newton acting over the distance of one meter per second. Power Joules per second or Watts Energy/time Energy Joules or Watt-second Power x time Joules or equivalently Watt-seconds are SI units international system of units.

Energy can also be measured in Watt-hours (Wh) or kilo Watt-hours (kWh), which is how your electricity use at home is measured and how you get charged for your electricity consumption every month.

A 100-Watt light bulb power rating is 100 W, left on for one hour it will use 100Wh of energy. In NYC it costs about 19 cents per kWh, so leaving your 100 Watt bulb on for 10 hours uses 1000 Wh or 1 kWh and would cost you $0.19.