What are the Independent/Dependent/Controlled Variables

AFTER you've done your research and concluded your experiments, it is time to prepare for the science fair. Ask specific questions about preparing for a science fair, including how to set up your display board, how to prepare a presentation, etc. (Please post questions about selecting a project or conducting your experiment by posting in the appropriate "area of science" forum.)

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Panina
Posts: 3
Joined: Tue Dec 30, 2014 12:24 pm
Occupation: Business Manager
Project Question: Generating Electricity from Fruits - Having trouble determining the variables (independent/dependent/controlled)
Project Due Date: January 5th, 2015
Project Status: I am just starting

What are the Independent/Dependent/Controlled Variables

Post by Panina »

Hello

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.

Nina
tdaly
Former Expert
Posts: 1415
Joined: Sat Nov 08, 2003 11:27 pm
Occupation: Planetary Scientist
Project Question: N/A
Project Due Date: N/A
Project Status: Not applicable

Re: What are the Independent/Dependent/Controlled Variables

Post by tdaly »

Hi Panina,

Science Buddies has a great article about identifying independent, dependent, and controlled variables. You can read it here: https://www.sciencebuddies.org/science- ... 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!
All the best,
Terik
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