Results – The visking tube with the sugar solution had expanded and the visking tube with the water had been emptied.
Conclusion – I have come to a conclusion that Osmosis occurred. I determined this by measuring the beakers, and then subtracting it with the measurement I took before to see whether it took place. I was correct when there was an increase in the sugar solution and a decrease in the water solution.
MAIN EXPERIMENT
PREDICTION- Osmosis is the passage of water molecules from a weaker solution into a stronger solution, through a partially permeable membrane. In this case, the tiny holes in the membrane of the potatoes will allow the water molecules to pass through in and out of the solution and the potato, depending on the concentration gradient of the two substances. So in this case, when the water concentration is lower in the tissue, the water will go inside the tissue of the potato, and the potato will gain weight. And if there is very little different in the two water concentrations, there shouldn’t be such a big change in weight. And if there is a higher concentration of water in the potato, the water will go out of the potato.
The potato, cut up into pieces, will need some sort of element to survive, and in this experiment, it would be light and water. With both of these sources, the potato will keep on working, until it dies of either lack of water, too much water. When the concentration gradient is lower in the potato, the water will transfer from the solution to the potato. And vice versa.
In the distilled water, I believe that the water is more concentrated in the potato, and therefore the water should transfer from the water to the potato, making the potato bigger in size, and heavier in weight. The potato tissues, being surrounded by a weak solution, will be most likely to swell up and become turgid, taking in all the water it can possibly take in.
With the potato in molar solutions of sucrose, I don’t think there will be much change in the weight of the potato. This is because there isn’t much difference between the two substances. I believe that the weight and the size of the potato won’t be altered much.
FAIR TEST- In this experiment we will only change one factor, the concentration of the solution, and the factors that I am going to keep the same are as follows:
We must keep the length and weight of the Potato exactly the same. A small difference could end up with anonymous results. I will be doing by using the same cork borer and measuring the length exactly and double-checking them. I must use the same cork borer because changing it would change the diameter causing the results to be inaccurate.
I also have to make sure that the whole potato is covered by the solution otherwise only part of the substance will diffuse.
I must also make sure than when making the solution, the total adds up exactly the same as the others and that it is very accurate because small difference between the concentrations will make anonymous results.
I will have to keep the room temperature warm enough for the solution not to evaporate. This could cause wrong results.
SAFETY- safety is very important in this experiment, especially with using knifes.
Safety is always an important aspect in every experiment even if it seems harmless. We will be using a very sharp knife, which could injure someone if it’s not used properly. We must also make sure that the substance shouldn’t get into our body systems just in case. Other than that, there aren’t any big matters to be cautious of.
APPARATUS - Cutting tile – to cut the potato on
Knife – to cut the potato
25cm Measuring Cylinder – to measure solutions
Distilled Water – to make solutions
Sugar – to make solutions
Potato – part of the experiment
Tissue Paper – to dry potato after osmosis takes place
Scale – to weigh potato
Cork Borer – to cut potato cylinders
12 Boiling tubes
METHOD – in total I will be doing 5 experiments. The first, keeping the length the same, the second, keeping the mass the same, then by choosing three different concentrations (e.g. 0.3, 0.4, 0.5, 0.6) and repeating each of those twice. First push the cork borer through the potato, cutting it in long cylinders with a diameter of 1cm and then I will cut the potato to a length of 20mm until I have 10 altogether. I will then make 10 solution between 0.0 Molar and 1M. I will them put each potato in a different concentration. I will then wait until the next lesson where take them out and measure them and record it in a table. You will find this underneath.
In the second experiment I will do exactly the same as above but keep the potato weight the same (e.g. 2.5).
After doing both experiments, I will chose 4 consecutive concentrations that have good results and do the whole of what I have stated above again but 3 times.
DIAGRAM –
MAKING CONCENTRATIONS
OBTAINING RESULTS – After the experiment, I had to dry the potatoes first so that the water inside the potato didn’t affect my results. The amount of water determines the weight of the potato. The less amount of water in the potato the better.
RESULTS –
Experiment 1
Experiment 2
I randomly picked a concentration and from that I determined to do that and the next three concentrations in sequence.
Experiment 3
