In my preliminary test I also noticed that the potato pieces needed to be left in the solution for longer then 30 minutes at least, otherwise change in mass isn’t very noticeable and made it hard to compare. I decided to leave the potato pieces in the solutions overnight.
Method
I will firstly cut up a potato into 6 visually equal small pieces using a scalpel and a cutting tile for safety. I will then use a balance to weigh the mass of the potato before I place it into any solution. Once I have completed the weighing process I will measure 8ml of distilled water (which has a MOL dm¯ ³ of 0) with a measuring cylinder before I place it into a test tube.
I will then put one of the sliced potatoes into the 8ml of distilled water and place a bung on the test tube before I put the test tube into a test tube rack. I will be repeat the same process for the other 5 solutions
I will use this method twice as I am planning on having 2 experiments running at the same time.
The ranges of sugar solutions I will be using are as follows:
Fair test
I feel collecting results using 5 different concentrations of glucose solutions, 6 including water, will be able appropriate for the amount of time I have. Also I feel it is enough results to help me conclude to a reasonable conclusion.
I will be running 2 experiments to gain a more accurate result. Also if I gain any anomalous results, by repeating my experiment twice, I will still be able to calculate an average.
I will make sure I have a fair test by not changing any of the properties in my investigation apart from the concentration of the solutions.
Another way I will keep my experiment fair is by making sure I get each potato slice from the same potato. This is so that I can be fairly certain each piece will have a similar genetic makeup.
When weighing the weight of the potato I will be careful not to lean on the balance or the bench. By not doing this there is a risk that I will gain the incorrect mass for the potato.
I will be taking care when removing the potato pieces from the solution and I will make sure I weigh the potato as soon as it is removed from the test tube. This will minimise the risk of any changes in temperature affecting the mass of the potato. For example, water loss due to evaporation.
I will make sure I label each test tube to ensure they do not get mixed up.
I will also need to think of a way to prevent any of the test tubes from losing any liquid. I need to do this because of various reasons, for example, if the temperature of one of the liquid solutions in a test tube increases, some of the solution will be caused to evaporate. This will then cause an unfair test because that test tube will no longer have an 8ml of liquid and will be at a disadvantage from the others. I will keep the temperature the same by using a bung to trap the solution in the test tube.
For my own safety I will handle the test tubes with care. I will avoid holding it near my eyes in case of splashing or in case a test tube breaks. I will use a cutting tile to ensure safety when cutting the potato. I shall also make sure I am very careful with the scalpel I will be using.
My prediction:
My prediction is that the solution with a moldm¯ ³ of 0.5 will cause the potato to decrease the most in size. I also predict that the potato in the distilled water will become harder.
I predict that the mass of the potato piece will decrease as the concentration in the glucose solution increases. I think that as the solution becomes more concentrated the increase in mass will begin to decline. Eventually this will cause the mass of the potato piece to decrease. The higher the solution’s concentration, the lower the mass with increase.
The scientific reason beginning when the solution’s concentration of glucose is low the water in the solution on the outer part of the potato cell is greater then the water inside the potato cell. By osmosis occurring the potato cells will take in the water solution. If the solution has a strong concentration of glucose osmosis will happen in reverse. Water will be drawn out of the potato cell into the solution.
Results
Investigation 1
Investigation 2
Graph to show the change in mass for investigation 1
A graph to show the change in mass form investigation 2
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