# osmosis- percentage increase

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1. osmosis- percentage increase
Why is it more useful to use percent change in mass rather than just comparing the 2 means and looking at hoe the mass changed?
2. Re: osmosis- percentage increase
What are your dependent and independent variables? Can you give more details on what is happening in the experiment?
3. Re: osmosis- percentage increase
(Original post by alkyone)
What are your dependent and independent variables? Can you give more details on what is happening in the experiment?
iv- different conc of salty water
dv -mass of potato
4. Re: osmosis- percentage increase
Alright, if the initial mass of each piece of potato is different, % change in mass allows you to take into account the initial mass of the potato, which influences how much water is lost. If the potato loses 0.1g of water and your initial mass of potato is 10g, it's no big deal, it's only 1% change in mass. If however your potato loses 0.1g of water and its initial mass was 0.5g of water, that is 20% change, so you can see that the same mass of water lost has a different significance depending on the initial mass of potato. This percentage change in mass can make you realize how significant the change in mass was.
5. Re: osmosis- percentage increase
(Original post by alkyone)
Alright, if the initial mass of each piece of potato is different, % change in mass allows you to take into account the initial mass of the potato, which influences how much water is lost. If the potato loses 0.1g of water and your initial mass of potato is 10g, it's no big deal, it's only 1% change in mass. If however your potato loses 0.1g of water and its initial mass was 0.5g of water, that is 20% change, so you can see that the same mass of water lost has a different significance depending on the initial mass of potato. This percentage change in mass can make you realize how significant the change in mass was.
so with % change are we finding the change for ALL the results or for each particular potato?

youre really helping me thanks
6. Re: osmosis- percentage increase
For each potato:
% change in mass= (final mass of potato-initial mass of potato)/initial mass of potato.
So you need to find %change in mass of each potato, to compare how the mass changes (% change in mass) with different concentrations of salt.
7. Re: osmosis- percentage increase
(Original post by alkyone)
For each potato:
% change in mass= (final mass of potato-initial mass of potato)/initial mass of potato.
So you need to find %change in mass of each potato, to compare how the mass changes (% change in mass) with different concentrations of salt.
but the next questions asks why id use percentage change for each conc because all the repeats have different initia lmass' of potatoes.
8. Re: osmosis- percentage increase
Ahh alright. Then you find the percentage change by getting an average of the initial and final mass. Sorry I didn't understand your question before. And the reason you are using % change in mass is what I explained before

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Last updated: May 8, 2012
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