- 1 Potato
- 1 Hole Cutter
- 1 Tile
- 1 Scalpel
- 6 Test Tubes/Beakers
- Test Tube Holder (for Test Tubes)
- 1 Stop Watch or Clock
- Paper Towels
- 1 Scale (for weighing)
Cut 6 pieces of potato using the hole cutter for a potato. Make them roughly the same size with no potato skin on them at all. Weigh and record the weight of each piece using the scales. Either using 6 test tubes or 6 beakers, fill each one up in correspondence to this table:
Leaving a minute in between each one place a piece of potato into each solution. After 6 minutes all of the pieces of potato should be in a piece Test Tube/Beaker. Leave for 25 minutes, take the 1st one out and weigh again, do with the rest making sure each gets 25 minutes in their solution.
These are the results from the experiment:
The results clearly show that there is a pattern. For the 1st piece of potato there was a weight increase meaning that it took in water and that there was a higher concentration of dissolved stuff in the potato. For the 2nd piece of potato there was no change at all meaning there was an equal concentration of dissolved stuff in the potato and in the solution. And for the 3rd to 6th there was a decrease in weight meaning there must have been a higher concentration of dissolved stuff in the brim than in the potato making the water move out though the selectively permeable membrane.
The graph shows us that the water potential of a potato cell is equal when there are 0.2 moles of salt in the solution. The curve on the graph tells me that the decrease in weight is slowly slowing down; even though the concentration of dissolved stuff is getting higher in the solution. This could be because of the time I left it for or there is only so much water that can come out of the potato cells, I would have to carry on the experiment to find out.
I could of made the test fairer by drying the scales before I put my piece of potato on, as there could have been water on them from previous tests. In overall I think I got quite could results, producing a good graph.