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Sample Variables & Hypothesis

Question

How does the voltage of an AA battery change over time when used in low, medium, and high current drain devices?


Hypothesis

If I use a AA battery in any current-draining device, then the voltage of the battery will drop over time. If I perform this test in low, medium, and high current drain devices, then the rate of voltage drop will be slowest in the low current drain device and fastest in the high current drain device.

There are two parts of this hypothesis, and thus two experiments:

Variables

Experiment #1:
Experimental Group Controlled Variables for Each Group
Low current drain Same portable CD player
Play the same music track
Play at the same volume level
Medium current drain Identical flashlight
Identical light bulb
High current drain Same camera flash
All groups Battery size (AA)
Constant temperature (A battery works better at a warm temperature.)
Battery brand
Voltmeter

Experiment #2: