Apparatus
- Beakers
- Water
- A potato
- Potato borer
- White tile
- Molar sugar solution
- Measuring cylinder
- Stop watch
- Ruler
- Electronic scales
Method
There won’t be much control for this experiment, because the weight would vary depending on the potato cylinders and therefore, it might affect the results, which I will take into account when writing up my evaluation after the experiment.
First I will have to get the pieces of potatoes ready. I will push the potato borer through the potato, cutting it into long cylinders with a diameter of 5mm. Then I will cut the potatoes into cylinders of 3cm, and weigh 6 sets of 3 potato cylinders. I need three potato cylinders for each set so I can get a set of reliable results. I will have 6 sets because we will have to test the potatoes in 6 different types of solutions; 0.2, 0.4, 0.6, 0.8, 1.0 molar solutions of sucrose, and distilled water (like shown in the table below).
I will weigh each set and have them ready for us to put into the test tube.
Then I will put the 6 sets of 3 potatoes in the 6 beakers at the same time and start the clock running for 145 minutes.
After 145 minutes, I will take all of the potatoes cylinders out of their beakers, so that the actual osmosis action stops. I will then proceed to weigh and measure the potatoes taking in the average reading of the 3 pieces.
I will only do this experiment once as this is only my preliminary experiment
In order to ensure a fair test, I will do the following:
- I will use cylinders from the same potato, as this will eliminate as far as possible any variation resulting from different treatment or source of supply.
- I will make sure that each cylinder of potato that I cut is of the same cutter (3cm long and a size 3 cutter); therefore, the experiment will be a fair one.
- I will make sure that I measure exactly the exact amount of solution needed for each experiment.
- I will also make sure to use a different measuring cylinder for measuring out the different solutions.
- I will also put the potato cylinders into there solutions at the same time and leave them in for the same time of 145 minutes so the action of osmosis stops at the same time for all of the potato cylinders.
The only variables in this particular experiment will be the amount of water and sugar solution used because these the only variables I will be changing for my second experiment, as long as I get good results.
In order to make sure that this experiment is a safe one, I will do the following:
- I will make sure that I set up the experiment away from any hazards, so it does not get knocked over.
- I will ensure that I keep the knife in a safe area when I am not using it, so no one accidentally cuts themselves.
- When using the potato borer I will take care to make sure that no one is near by, so if I slip I don’t hurt anybody.
Results
My results are shown on the following page headed “Results”.
Conclusion
From looking at my results I have decided to investigate further when the pure water is at 80 to 100 and the pure molar is 20 to 0. This is because it is at this particular position it is increasing in length, so it is around this point were it is the same as the cell sap.
