Osmosis and potatoes - I need help with this prac, desperately... (Feb/15/2006 )

Has anyone done this prac? I need help with it.
What happens is there are six beakers, all filled with water. The first one has 0% NaCl, the second 0.5% NaCl, the next 1%, the next 2%, the next 5%, and the last one 10%. We get 12 pieces of potato pieces the same size. 2 to go into each of the beakers. But before we add them to their NaCl solutions, we weigh them, record the initial mass. After half an hour, the pairs of potatoes are taken out and weighed again, so we'll have 6 sets of final masses. Then we find the change in mass for each beaker, and the % change in mass for each.
Now, I really really need help with these two questions about it:
1. Describe two control measures taken in this experimental procedure.
2. Outline two limitations related to this activity.

asap, please, I NEED to figure this out REALLY soon!! I'm doing a sac on this tomorrow!

a classical google search in google on osmosis principles will do the job.

What do you mean? How will that help? =S

you will be able to get some courses and read sthg about it.
hmmm....LODYH?

I think I would check here

fred, you rule

fred u really rock