heidilockyer
Posts: 3
Joined: Wed Nov 14, 2007 6:14 pm

I need help with Manipulated and Responding variables.

I am currently doing a project from this site, measuring the sugar content in water with a laser pointer, could someone please help me with the manipulated and responding variables, if you could it would be greatly appreciated. thank you.

Craig_Bridge
Former Expert
Posts: 1297
Joined: Mon Oct 16, 2006 11:47 am
What is your hypothesis? A hypothesis often provides the clues to how to classify each variable involved.

How about posting your hypothesis and your guesses at what the manipulated and responding variables are?

You will learn more if you take a guess even if you are wrong. In my experience, I learned far more when I was wrong about things to start with than when I guessed correctly so don't be afraid to be wrong. The scientific method is all about finding out if you are right or wrong.
-Craig

heidilockyer
Posts: 3
Joined: Wed Nov 14, 2007 6:14 pm

my hypothesis

My Hypothesis is "We think that the sugar concentration will be different in each liquid. Also we think that there will be a major difference in sugar concentration between diet and regular soda, compared to the different sugars.".

i think that the manipulated variable could be the amount of sugar.?
and the responding variable could be the index of refraction?

Craig_Bridge
Former Expert
Posts: 1297
Joined: Mon Oct 16, 2006 11:47 am
i think that the manipulated variable could be the amount of sugar.?
and the responding variable could be the index of refraction?

Manipulated variables are something that you directly change. Because your experiment involves measuring liquids with unknown sugar content, you aren't directly manipulating the amount of sugar.

The index of refraction is definitely a responding variable!

Now to your hypothesis:
"We think that the sugar concentration will be different in each liquid. Also we think that there will be a major difference in sugar concentration between diet and regular soda, compared to the different sugars.".

Various artificial sweeteners and other substances will cause the index of refraction to change as well. There will be no correlation between the concentration of different substances and their refraction index.

There should be a correlation between different concentrations of the same substance. Might not hold for all substances as some might not change the index of refraction much.

With this in mind, you probably need/want to revise your hypothesis.
-Craig

heidilockyer
Posts: 3
Joined: Wed Nov 14, 2007 6:14 pm
Thank you so much for your help.

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