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Objective
To show young students how different uses of electricity and electrical power produce different results, leading to thinking about how to use power best for better results in energy conservation.
Things to Keep in Mind
When planning this lesson, think about common household appliances that run on electricity, and specifically, on battery power. Think about the results of draining power from battery-powered objects. You will want to show students verifiable results that will make sense to them. For younger students, this means a simple flashlight or other light producing device can be the best tool. Other good options are electrical audio devices that slur or slow sounds when the batteries are drained. Think about whether you can get best results with digital devices or analog, where there is greater potential for dramatic results from drained batteries.
Materials
- Two or more of the same battery-operated home appliances or devices
- Tape and marker for labeling
Asking Questions: Lead-In
For getting students ready for a “lab” exercise, talk about how simple home items work. Ask students to explain their concepts of electricity: what makes flashlights light up, and how batteries allow music to be played on audio devices (yesterday’s walkman or portable radio, or today’s MP3 player or iPod).
Then ask students to predict what happens when energy gets “low” or when these simple home appliances are left on. Have students think about the end result of not turning off battery-powered appliances.
The “Lab” Activity
For this comparative lab, you’ll want to model different levels of energy use and battery drain. Start by labeling each of your devices according to the time you will use energy and thus drain the battery.
One option is to label the first device “5” or “10”, and ask students to time the device being left on for 5 or 10 minutes before being switched off. The other can be labeled “30” or “40” and left on the length of a lecture or other activity. A third device could be left on “all day”.
This lab should take place over several sessions, in which students can be doing other group work related to energy use. It may be necessary to use pre-drained batteries in order to time the activity to the advantage of a classroom schedule.
Results
When the first device finally starts to fail due to battery drainage, have students record what happens to the item. Flashlights or other lights may get dim, or flicker. Sound objects may get staticky or work in bursts. Analog sound objects might get “tape lag” where sounds are distorted (this is great for an effective demonstration).
Allow students to notice that after the battery is initially drained, the device might still work if it is switched off and then on again. This can be a neat side lesson about how each appliance uses battery power.
Follow-up
Ask students to write alone or in groups about the effects of energy use on an appliance, and have them also report their ideas on how to use batteries best.
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