This lesson is designed to allow middle-school students (and others) to explore power and energy usage in the home. Power comes from a power plant to your home through a system of power lines, power substations, and transformers that make up the power grid. This Java applet shows power flowing through the transformer drum, the meter, and into the home circuit breaker panel. From there, it powers various appliances. Users can open and close switches to turn appliances on and off and track power usage and learn concepts such as power conservation, network flows, and the relationship between power and energy. An appliance's energy use and cost depend both on the amount of power needed for its use and on the amount of time the appliance is used. Some appliances require a lot of power, but we don't use them often, so they don't use much energy over time. Other appliances may not need as much power, but are used for more time. For example, a toaster needs a lot more power than a room air conditioner does, but most people use a toaster for much less time.
Set the blue switches so that only the Energy Star refrigerator ('E-Star Fridge' under Kitchen Appliances) is on. What is the Current power consumed? (It's the green number near the bottom of the pole.) Compare the Energy Star refrigerator with the standard refrigerator. About how much more power does the standard refrigerator use?
Resources for Students and Teachers
We have recorded a short tutorial for this applet, to help familiarize you with how to use it.
Use this quick-start guide to learn about the features of this applet.
Lessons have been created to help you use this applet in your classroom.