Water potential of potato cells experiment.

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Water potential of potato cells

Aim: To investigate the effect of varying concentration of a certain sugar solution on the amount of osmotic activity between the solution and a potato chip of a given size.

Hypothesis: The potato chips left in dilute solutions will increase in size, while the potato chips left in the concentrated solutions will decrease in size. This is because the water in hypotonic solutions will move into the potatoes (where there is a lower concentration) increasing its mass and vice-versa.


Cut 8 peeled potato chips 30mm long.

Blot each chip dry and mass accurately to 2 decimal places and then measure elasticity of chips.

Then immerse each potato chip in eight different solutions of sucrose: 0.0M, 0.1M ,0.2M, 0.3M, 0.4M, 0.5M, 0.6M, 0.7M

 Leave the chips for 30mins.

After 30mins record the new mass of each chip and change in elasticity


Distilled water:-
The potato chip increased in mass. It was also very rigid and hard. 

0.1M solution:-
The potato chip increased in mass. It was relatively hard and rigid but not as much so as the chip immersed in distilled water. 

0.2M solution:-
The potato chip decreased slightly in mass. It felt the same as before

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0.3M solution:-
The potato chip decreased in mass. It was a bit softer than before submersion. 

0.6 M solution:-
The potato chip decreased mass. It was very soft and flexible. 


Percentage mass change = [(final mass - initial mass) ÷ initial mass] x100

The percentage change in mass was calculated in this experiment instead of the change in mass alone because not all the chips were the same size at the beginning of the experiment, meaning that some chips would be able to take in more or lose fewer substances through osmosis because they had a greater ...

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