luma007
Posts: 7
Joined: Mon Nov 26, 2012 1:04 pm
Occupation: parent

### Dependent Variable ?

Hello. My child is doing his science fair project on which disinfectant works best : natural vs chemical. He used slimy bologna on a cutting board and took samples of several disinfectants and observed which disinfectant had the fewest bacterial colonies on several petri dishes with agar. We know that the independent variable is the disinfectant, but what is his dependent variable? Thank you!

klhjbh62604
Posts: 22
Joined: Thu Sep 06, 2012 9:37 am
Occupation: Scientist

### Re: Dependent Variable ?

Hello luma007:

What a great project for a young student. Way to teach a child the need to clean surfaces.

You are correct in that the disinfectants are the independent variable.
The dependent variable represents the output - in this case it would be the slime of the bologna that would be on the cutting board. You are testing the disinfectants on their ability to clean the slime off the cutting board.

I hope this helps.
klhjbh62604

luma007
Posts: 7
Joined: Mon Nov 26, 2012 1:04 pm
Occupation: parent

### Re: Dependent Variable ?

Thank you so much for your response. Would it also be correct to say that the dependent variable is the number of bacterial colonies formed?

drowningfish
Former Expert
Posts: 54
Joined: Wed Aug 18, 2010 4:10 pm
Occupation: Student: College Third Year

### Re: Dependent Variable ?

Yes, it would be.

KrishnaPatel
Former Expert
Posts: 66
Joined: Fri Nov 11, 2011 3:06 pm
Occupation: Student: 12th grade

### Re: Dependent Variable ?

Just so you, and other people know, the dependent variable will always be what you measured in the experiment.

I hope his helps!
Meg
“Nobody important? Blimey, that’s amazing. You know that in nine hundred years of time and space and I’ve never met anybody who wasn’t important before.”
— The Eleventh Doctor

murwarid3
Posts: 5
Joined: Tue Sep 03, 2013 6:34 pm
Occupation: student: grade 11

### Re: Dependent Variable ?

Hi,

Yes, just for a tip, the dependent variable is the results. Think of it as the dependent depends on the independent, the result.

Hope this helps!

Thanks,

Murwarid