## Osmosis Potato Prac

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Aerlinn
Posts: 68
Joined: Wed Oct 12, 2005 11:34 am

### Osmosis Potato Prac

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!

The wonders of so-called life...

Poison
Inland Taipan
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Location: Turkey
I'm not good at this stuff but control measesure can be the salt concentrations.
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cool A-level student
Posts: 61
Joined: Thu Nov 24, 2005 11:19 am
1. well control measures are basically wat u hve to control for the experiment to be fair like the salt conc. or the potatoes size, the only thing that should vary in teh ebakers is the conc. of the salt otherwise the eexperiment isn't fair and your results may look funny.

2.limitations are harder.....well the way i see it is wats limited? well you dont know how much water has entered the potatoe by just weighing it for a start and so that limits the results, also there may be some kind of environmental effect on the potatoe that makes the results go "wild" record your results in a table and see if there are any anomalies on it (see if a pattern is there that say one result doesn't fit in and mention it by saying its anomalous! as it doesn't fit the pattern)
thats all i can think of atm but ill see if i can think of anythin else

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