Pathway: Observing the World Around You

How much electricity does a toaster use? How about a T.V. or a cell phone charger? Investigation how much electricity an item uses, whether it's on or off, can help us make better decisions and save energy. 



• A phantom load is the amount of energy a device consumes while in standby or sleep mode, or while turned off.
• The off button on many appliances may not really mean off; instead, it means standby. For example, appliances with remote controls or internal clocks—such as TVs, DVDs, and microwave ovens—have phantom loads. Other appliances with phantom loads include computers, printers, and plug-in battery chargers such as those for cell phones, iPods, and cameras.
• Use of a power strip can minimize the phantom energy load loss. Plug all components of a computer, TV, and so forth into the power strip. Turn off the power strip with a single switch. Anything plugged into the strip now is truly turned off.
• You can also unplug appliances when not in use.

To investigate how much energy is being used by items in your school, choose 5 items and put them in standby mode, plug them into a power strip, and then plug the power strip into a watt meter. Finally, plug the watt meter into a wall outlet. Leave the items plugged in for the school day or for 24 hours, whichever is more convenient for you.

The watt meter will provide a readout of how much electricity the items used during that time period. If you get the cost per kilowatt hour (kWh) of electricity in your area (obtained from the electric bill or from using the national average of $0.10 per kWh), you can calculate the cost of keeping those appliances in standby mode for a specific amount of time.

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