I have decided to predict that this will happen because of the theory of osmosis, which is a special case of diffusion, where water molecules move from a high concentration to a lower concentration, across a semi-permeable membrane.
Also for my prediction, I believe that the will be a certain solution where if the potato is put in, it will neither gain nor lose mass. It will remain the same.
Diagram:
Fair testing:
I am going to try and ensure that I carry out a fair test because if I don’t, I may get inaccurate, or wrong results. Which may result in me making a wrong conclusion.
Firstly I will have to try and make sure that the volume and the weight of the different potatoes are as similar as I can possibly make them. I will be using a very sensitive balance so that I can get their weights as similar as I can.
I will be carrying out my experiment at room temperature, which is roughly 18c, and I will try and keep the temperature constant, i.e. keep out of sunlight, keep away from heaters, windows. And I will be making sure that all the equipment that I use will be sterile, and not damaged in any way because this may have an affecting result on my conclusion. Also I will be repeating the test three times so that I can get an average results which is a more reliable way to collect my data.
Safety:
Safety is an important part of every experiment, even if it seems to be very harmless. In my experiment, I will be using a very sharp knife, which could be dangerous if not handled with care. I must also ensure that the solutions do not enter our bodies internally, because we are not fully aware of the damage that it could do to us. Other than that there are not really any other safety issues in this experiment.
Method:
Firstly I will get the pieces of potatoes ready, I will push the borer through the potato, cutting it into long cylinders. And I will cut out 5 of these because I am going to be testing these in five different solutions of sucrose solution, 0.1, 0.2, 0.4, 0.6, and 0.8.
I will weigh each set and have them ready to be put into the test tube of the different solutions. Once I have put them in I will start the stopwatch and will leave the potato cylinders in there for five minutes. Then once the five minutes are up, I will remove the potatoes, and blot dry tem with the tissue paper. This will ensure that I weigh only what is in the potato and not any liquid which may have been left on the surface. Then I will weigh them. Then I will record my results down onto a table. And I will repeat this three times to ensure the fair testing, and to make sure that there are no anomalous results which would have corrupted my conclusion.
Obtaining evidence:
Below are my results that I collected from my experiment.
1.
Average results
Analysis:
It is visibly evident in my graph that I have drawn and in my tables that my prediction, due to my scientific knowledge and research was accurate.
Looking at my three tables and the average results from the tables, it is clear that the higher the concentration of the solution the more mass lost from the potato will be. This is shown even more clearly in my graph.
These results show that the water is moving from a high concentration to a low concentration, which is called Osmosis, where the water diffuses through a semi permeable membrane, from a high concentration to a low concentration.
In my graph that I have drawn, with it now I am able to make fairly accurate predictions of the percentage of mass change for other sucrose solutions, which I did not test. In my prediction I said that I believed that there was a solution of sucrose in which the potato will neither gain nor lose mass. On the graph on the vertical axis, if we look and the average percentage change as 0% and then move across the horizontal axis, until you get to the point of where the graph line crosses over, we can see that a sucrose solution of roughly 0.3 molar will be the solution of where mass is neither gained or lost. Also this would be the concentration of the solution inside the potato.
Evaluation:
The experimental set-up was fine in showing the effects of osmosis in a potato. I am very pleased with my experiment and I believe it went very well, I came across no difficulties and there wasn’t any anomalous results.
I am certain that my results that I obtained were accurate when I carried out the experiment. I believe this because out of the three times that I carried out this experiment, they all showed virtually the same results.
My results all agree with my prediction that the higher the concentration of sucrose solution the more mass the potato will lose and vice versa.
My results also concur with the osmosis theorem. Osmosis is a special case of diffusion, where water molecules move from a high concentration to a low concentration, through a semi permeable membrane.
If I were to do this experiment again, in order to improve it, I would do it using a greater range of concentrations to obtain more accurate results so that I am able to produce more accurate graphs. I would also measure the change in size of the potato pieces.
