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variable and control

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variable and control

Postby hobaoau » Sun Mar 11, 2007 10:21 pm

When i carried out an experiment about osmosis in plant cell, i can not distinguish variables from control.
first the plant cells were placed in distilled water
then the salt solution were added, the cells became flaccid
then the distilled water were added, the cell go back as normal

in this case which are variables and which are controls?
and could u explain me why
anyone can help me, thanks
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Postby Darby » Mon Mar 12, 2007 1:51 am

This is more a demonstration than an experiment - that's one of the reasons you can't apply those labels.

And even if you did, there is no control here. The variable is water concentration.
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Postby hobaoau » Mon Mar 12, 2007 6:16 am

So how about in this case:
beetroots was placed in 3 petri dishes
1- water
2- detergent
3- acid
so identify the variables controls
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Postby mith » Tue Mar 13, 2007 1:54 am

Usually a control is used to make sure that certain aspects of of the experiment are functioning as they should be. For instance, if you knew how beetroot would react in acid, you could use that as a control and compare its results to those placed in water and detergent.

*note, I said for instance.
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Postby Dr.Stein » Tue Mar 13, 2007 3:27 am

I see there is no control for those both experiments. If you still want to have control, it can be plant cells and beetroot which do not treated with anything, not with distilled water, salt solution, acid, detergent, or else, just plant cells and beetroot :)
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