Science Buddies: "Ask an Expert"

Hi. I am doing the science fair project from Science Buddies: Crime Scene Chemistry: Determine the Identity of an Unknown Chemical Substance. I am having difficulty determining the Independent Variable and Dependent Variable for this experiment. I am currently completing an Experimental Design Diagram and need assistance in finding these variables. My parents ordered the kit and it arrived yesterday, but I need to identify the variables first. IT IS DUE TOMORROW 9/18/13.
I live in the mountain time zone. Can I have help quickly?

Thanks!!

7th Grader at Arizona College Prep

Hi,
I read the Methods for the forensic chemistry project and what you are doing is performing three tests on each unknown substance and comparing the results to aspirin. An independent variable is what you do to a sample--adding the test chemicals in this case--and the dependent variable is the result. These tests are called qualitative because you are not actually measuring the result quantitatively. Either the test is positive or it is negative.

Here's the link to the description of variables in an experiment: https://www.sciencebuddies.org/science- ... bles.shtml

If you have any more questions, please repost and i will try to help you before you have to turn in the project.

Good luck!

SciB