With the higher concentrations of sugar water from the cytoplasm will move out in varying degrees first making the cell flaccid because the cell is no longer under the osmotic pressure which it needs to keep the cell firm with even higher concentrations the cytoplasm will shrink so much that it will be pulled away from the cell wall known as plasmolysis.
Preliminary work
Before starting the experiment proper we decided to carry out some preliminary work as a trial run to discover and hopefully overcome any problems which might affect the actual experiment.
We used varying sizes of potato chips to try to discover the optimal size of potato for the most reliable results.
After testing each potato and noting its weight after being placed into a sugar solution of 0.0M we decided that the best size was 2.7CM
To make our results more reliable we decided to place three potato chips into each solution, this however created a problem for us in that the size of the beaker was in fact too small to allow three potatoes to float freely in so we decided to move up to 500ml beaker this allowed each potato enough room to get an even amount of solution.
Method
To measure how osmosis affects a potato I will need to accurately measure the weights of each potato measure the mass of the potato is an accurate way of measuring the rate of osmosis because as water moves in and out of the potato and water has mass the mass of each potato will therefore increase or decrease.
We will be observing the effects of five different solutions on the potato chips these will be.
- 0.0M
- 0.5M
- 1.0M
- 1.5M
- 2.0M
We will take potato chips each measuring 2.7cm in length pre-determined from our preliminary results 1cm in depth and 1cm in width, we will place the chips into 5 separate 500ml beakers (also pre-determined by our preliminary work) each containing three chips we will take the percentage of weight lost from each of the three potatoes and then take a mean average of from those three values.
After two hours the potatoes will be removed from the sugar solution, any excess sugar solution will be dried off and then each potato will be weighed individually.
To keep my results reliable I will need to keep everything constant and only one controllable variable this variable will be the concentration of the solution everything else will be kept as far as possible the same.
Where possible all my measurements will be made to 2 decimal places.
Before Osmosis
After Osmosis
I then decided to take a percentage of how much each potato lost or gained the results are as follows:
I then took a mean of each potatoes percentage.
Analysis
From my results I can conclude that as the concentration of the solution increases so the mass of a potato placed into that solution decreases.
However when a potato is placed into a solution of 0.0M (Water) the mass of the potato increases this is due to Osmosis.
Osmosis is the movement of water through a semi-permeable membrane, water moves from a high concentration of water and therefore a low concentration of the solute to a low concentration of water and therefore a high concentration of the solute.
Because water moves in and out of these cells and water has mass the potato will gain or lose weight
