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What are the Independent/Dependent/Controlled Variables

Posted: Tue Dec 30, 2014 12:46 pm
by Panina

The topic my son selected is: Generating Electricity from Fruits. I am having trouble figuring out the Independent/Dependent and Controlled variables.
The procedure we found is the following:

Making electricity from chemicals is based on the same scientific principles on which all modern batteries work. You insert copper and zinc electrodes in an acidic liquid and produce some electricity from the chemical reaction between your electrodes and electrolyte. The electricity produced in this way can be displayed with a multi-meter that can show millivolts. It may also be able to power up a 1.2 Volts light bulb.

I appreciate the help and guidance.


Re: What are the Independent/Dependent/Controlled Variables

Posted: Fri Jan 02, 2015 10:32 am
by tdaly
Hi Panina,

Science Buddies has a great article about identifying independent, dependent, and controlled variables. You can read it here: ... bles.shtml.

In short, the independent variable is the thing that you change. For example, if you are testing different kinds of fruit (e.g., oranges vs. lemons), then your independent variable would be the type of fruit. The dependent variable is what changes in response to variations in the independent variable. In fruit battery experiments, the dependent variable is usually a voltage. Controlled variables are the things that you keep the same in all of your experiments. Examples of controlled variables might include using the same multimeter for all measurements and using the same kind of wire in all your experiments.

Post back if you have other questions!