Find out if osmosis occurs in a potato, and how it affect the potato in different molar solutions of sucrose and water.

Osmosis

Aim:

My main aim in this experiment is to find out if osmosis occurs in a potato, and how it affect the potato in different molar solutions of sucrose and water.

Apparatus

· Stop Clock - to time our experiment
· Cutting tile - to cut the potato on
· Knife - to cut the potato
· 25cm Measuring cylinder - to measure the solutions
· Distilled water - part of the experiment
· sucrose - part of the experiment
· Potatoes - part of the experiment
· Tissue paper - to dry the potatoes after the osmosis takes place
· Balance - to weigh the potatoes
· Cork borer - to cut out potato cylinders

Planning

Before actually planning the experiment, I will do some research to find out about osmosis, and matters related to it, so that I can make predictions. And figure out a way to make this investigation fair and safe.
Planning ahead would help me find out how to do what, when, which should lead me to good results at the end of the experiment.

Hypothesis

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.
The 0.4 molar solutions of sucrose, similar to the 0.2 molar solution of sucrose, compared to the potato, both substances have very close concentration gradients. And that is why I am predicting that the weight of the potato in this experiment should be decreased by only a fraction.
The 0.6 molar solution of sucrose, I think, should make a big difference now, noting that it should be a large difference between the two concentration gradients. And there fore the weight should decrease, at least noticeable for us to notice.
The difference between the water concentration in the potato and the 0.8 molar solution of sucrose is big, and the water in the potato should be transferred from the potato, through the permeable membrane, to the solution surrounding the potato. And as a result, I am sure that the weight of the potato will increase largely. And because the potato tissues are surrounded by a stronger solution, it will probably become smaller, and shrink. But because of such high molars of sucrose, the water can diffuse all the way, throughout the two substances, equalling the concentration gradient of the two substances.
My theory in this experiment is that, due to the difference in the water concentrations of the two substances, I believe that the weight of the potato will start decreasing when it is tested on 0.2 molar solutions of sucrose and greater. By researching information about osmosis, and making predictions of the results, I believe the graph would look something like this:

Fair Test

Fair testing should play a big part in this experiment. If this experiment isn´t a fair test, we will be obtaining the wrong results, which could lead us to the wrong conclusions.
First of all, and most importantly, we will have to get the measurements and the weights of the solutions and the potatoes as exact, and as accurate as possible. We will try and get the measurements of the potatoes as accurate as possible for every single potato, evenly cutting the potato pieces, and making a record of the length to the nearest millimetre. And we will be using a very sensitive balance so that we can get the best readings possible.
But I believe one of the most important step in the fair testing is to make sure that the potato is fully covered by the solution. This is because the potato should fully submerge, by having total contact with the solution.
When using the balance, we will make sure that the balance is reading zero with the small foam bowl, before we put the 3 potatoes on it. This is so that we don´t get a false reading, with the weight of our potato with the reading it had before. And after the experiment, we will measure the 3 potatoes that should be dried as possible, and weigh it the same way, taking the reading to the nearest 2 decimal places.
And we will also be reading the measurements of the measuring cylinder by reading the bottom of the meniscus.
Carrying out the experiment in a constant temperature for the three hours of experiment is important. And to avoid temperature change, which might affect our 3 different sets of results, we will take the temperature of the solution into account.
Another important factor of a fair test is to start and stop the clock as quickly as possible. This meaning that we should start the clock as soon as the potato is put inside the test tube, and stop the clock as soon as 20 minutes have passed. Stopping the clock, taking them out and measuring it all in less than a minute us quite impossible because we lack the number of balances. And there are obviously too many sets to go through at such a fast time. Therefore, we will try our best to weigh the potatoes as quickly and as safely as we can.
Getting and experimenting with the exact measurements of molars and water is vital to this task. If the volume of one solution in a test tube is higher or lower than another, will affect the pattern of results later on.
We will also make sure that the potato is fully covered by the 6 different kinds of solutions. This is because, is the potato isn´t covered up by the solutions, the effect of osmosis might not occur to the fullest.
Small things such as a dirty test tube, and a slightly cracked measuring cylinder could still affect the results, and therefore we will take these into account as well.

Safety

Safety is an important aspect in every experiment, even if the experiment seems to be very harmless. And that is why we take this into consideration, no matter what.
We will be using a very sharp knife, which could injure someone if it´s not handled properly. And we will also be careful that the solutions don´t get into our bodies internally, just in case, because we are not fully aware of the damage it could do to us.
But other than that, there weren´t any bigger matters to be cautious of.

Method

I believe this task is very simple and should ...

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Safety

Method

I believe this task is very simple and should be very easy to carry out the experiment. The investigation is very straightforward.
There won´t be any control for this experiment, because the weight would vary depending on the potato pieces. And therefore, it might affect the results, which we are going to take in after the experiment.
First I will have to get the pieces of potatoes ready. I will push the cork borer through the potato, cutting it into long cylinders with a diameter of 6mm. And then I will cut the potatoes into cylinders of 40mm, and weigh 6 sets of 3 potato cylinders. 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.
I will weigh each set and have them ready for us to put into the test tube.
Then we will put the 6 sets of 3 potatoes in the 6 test tube at the same time and start the clock running for 10 minutes.
After 10 minutes, we will take all of the potatoes out of the test tube, so that the actual osmosis action stops, and we will put the potatoes onto one piece of dry towel, in their own groups. We will dry them with the tissue paper, in sets of 3, and weigh and measure the potatoes taking in the average reading of the 3 pieces.
We will repeat the experiment three times so that we can make sure that all our results are similar, and so that we will be able to take the average of the 3 experiments. This makes sure that we get accurate results. Repeating the experiments are important, because we will be able to receive valid results, and look for any anomalous results. Not to mention that we will take the fair testing into account.

Obtaining evidence
After the experiment, I had to dry the potatoes first, so that the water outside the tissue of the potatoes won´t alter the weight of what it is supposed to be. I quickly took all of them out, and put them onto a piece of tissue paper, into their own groups.
When obtaining my results, I reset the balance, so that it would read zero with the small foam bowl on top of it. This was because, if I had weighed the potatoes with the bowl, then I would have to take the weight of the bowl away from that result.

Table of results
In the table below, it shows the 'solution´ column, which are the 6 different types of solutions. The 'number of test´ column, which shows the number of tests that took place, and the average of the three tests. The weight before and after the experiment represents the 3 sets of results and the average taken out of the three. The increase/decrease of the weight is calculated by taking the weight after, minus the weight before. The percentage increase/decrease of the weight of the potato is calculated by taking the weight increase/decrease divided by the original weight multiplied by a hundred. This should help us lead to a more accurate result, and the average percentage will be used to present the graph.
solution no. weight Weight percentage change
In Water Before after weight + or - (%)
1 5.87 5.89 0.02 0.41
2 5.81 5.84 0.03 0.62
3 5.85 5.88 0.03 0.62
AVERAGE 5.84 5.87 0.03 0.55
0.2 molar
1 5.85 5.85 0.00 0.00
2 5.83 5.84 0.01 0.21
3 5.84 5.84 0.00 0.00
AVERAGE 5.84 5.84 0.00 0.07
0.4 molar
1 5.87 5.69 -0.18 -3.70
2 5.66 5.51 -0.15 -3.22
3 5.74 5.62 -0.12 -2.53
AVERAGE 5.76 5.61 -0.15 -3.15
0.6 molar
1 5.87 5.63 -0.24 -4.93
2 5.86 5.57 -0.29 -5.97
3 5.88 5.55 -0.33 -6.76
AVERAGE 5.87 5.58 -0.29 -5.89
0.8 molar
1 5.81 5.49 -0.32 -6.65
2 5.62 5.22 -0.40 -8.66
3 5.86 5.53 -0.33 -6.79
AVERAGE 5.76 5.41 -0.35 -7.35
1 5.64 5.23 -0.41 -8.84
2 5.86 5.51 -0.35 -7.20
3 5.80 5.39 -0.41 -8.54
AVERAGE 5.77 5.38 -0.39 -8.18

Analysis
On the graph shown below, I have made the 'different solutions´ as my independent variable, since it won´t be changing on any event. And I have made the 'percentage´ as my dependent variable, because it doesn´t change in any particular order or a pattern. I have decided to make it a bar graph, because the independent variables aren´t exactly in the same category. For example, I would have used a line graph if the independent variable in my experiment was time, which is changed deliberately, but these is different subjects of matter. And also, the results were very different, as well as the columns and there wouldn´t be any advantages of using a line graph to view the results. I have taken the average result of the 6 different solutions and put it on the graph to be more accurate.

Conclusion
In this experiment, I believe that I have collected enough data to support my hypothesis. This investigation was, I think, successful. Successful meaning my results collaborated my predictions.
The potato cells, working to stay alive, took in, or gave out the water depending on the concentration of the tissue, and the concentration of the solution it is surrounded in.
The results were fine and by looking at the weights measured before the experiment, you can see that there is no reading which seems to be out of the line. As the weights before the experiment range between 5.62g and 5.87g, this tells us that the potato pieces were cut well, and I believe accurate enough. There were, I believe, no anomalous results after the experiment as the weights were very similar in their own category. And this tells us that my experiment was successful.
The graphs and the results show that:
v Osmosis actually took place in the experiment.
v As the molars increased, the percentage of the weight difference decreased.
There doesn´t seem to be any results, which undermine my predictions, and our group didn´t find any anomalous results, which means we didn´t have to repeat any of our experiments more than three times.
Having the results which backs up my hypothesis, proves that this investigation was fully accomplished, and was an achievement.

Solution Weight Weight Weight + or - Percentage change
Before(g) After(g) (g) (%)
water 5.84 5.87 0.03 0.55
0.2 5.84 5.84 0.00 0.07
0.4 5.76 5.61 -0.15 -3.15
0.6 5.87 5.58 -0.29 -5.89
0.8 5.76 5.41 -0.35 -7.35
1 5.77 5.38 -0.39 -8.18

In the table above, the percentage shows a steady decrease, telling us that the percentage of the difference decreases as the water concentration decreases.
This experiment helped me find out that osmosis occurs between 2 liquid substances with a partially impermeable membrane, and that higher the water concentration is, the larger increase in grams. This means that the percentage will also be higher, increasing with the gram.

Evaluation
We followed the plan correctly, I believe we gained accurate and sufficient enough results to conclude the experiment, and to prove our hypothesis.
My final results were very reliable, due to the precautions I took to make this a fair test.
To make this experiment better, I believe that we could have done one test at a time, so that we can reduce the time difference, when we have to move the potato from the test tube to the balance. Between this, we have to dry the potatoes just enough, and then put it on the balance. When we are doing this for one set, writing down the results at the same time, while the other 5 sets are on the tissue paper, the water outside the potato tissue is going to vary for all. Therefore, we would be able to concentrate more on one of the sets, instead of trying to finish all of them as quickly as we can.
We also could have got more people to do the experiment with us, so that we can organize the tasks, and we would be able to divide the tasks.
Using more types of molar sucrose solutions would have helped us obtain better results, and more accurate results, so that we can make sure the results are totally correct.
Experimenting with one set for a longer period of time, for each set, would lead us to better results, because the osmosis action would reach its maximum capability, and therefore tell us how much water could be transferred for each solution.
Repeating the same tasks many other times wouldn´t have been very useful, since we had already done the result 3 times, and ALL the results were reliable.
Even though we didn´t use these experimental plans, we still got results which were correct, according to my hypothesis, and backed up my predictions.
But overall, given the apparatus that we got to carry out the test, I think this experiment turned out to be very successful, and I´m very please with my results.

Osmosis

Aim: To investigate the effect of varying concentration of a certain sugar solution on the amount of osmotic activity between the solution and a potato chip of a given size.

Hypothesis: Osmosis is defined as the net movement of water or any other solution¡|s molecules from a region in which they are highly concentrated to a region in which they are less concentrated. This movement must take place across a partially permeable membrane such as a cell wall, which lets smaller molecules such as water through but does not allow bigger molecules to pass through. The molecules will continue to diffuse until the area in which the molecules are found reaches a state of equilibrium, meaning that the molecules are randomly distributed throughout an object, with no area having a higher or lower concentration than any other.

For this particular investigation I think that the lower the concentration of the sugar solution in the test tube the larger the mass of the potato will be. This is because the water molecules pass from a high concentration, i.e. In the water itself, to a low concentration, i.e. In the potato chip. Therefore, the chips in higher water concentrations will have a larger mass than in higher sugar concentrations.

The graph above shows a simple curve obtained when the concentration of the solution is plotted against the percentage change in mass.

"Y At point A the graph tells the viewer that no osmosis has occurred, suggesting that the concentration of water inside the cell is equal to the solution outside.

"Y At point B (high water concentration), there is no indication that the cell is increasing further in size. This is because the cell is fully turgid and no more water can enter.

"Y At point C (low water concentrations), there is no indication that the cell is decreasing further in size. This is because the cell is fully plasmolysed and no more water can leave the cell.

Further information on potato plant cells:

Plant cells always have a strong cell wall surrounding them. When they take up water by osmosis they start to swell, but the cell wall prevents them from bursting. Plant cells become "turgid" when they are put in dilute solutions. Turgid means swollen and hard. The pressure inside the cell rises and eventually the internal pressure of the cell is so high that no more water can enter the cell. This liquid or hydrostatic pressure works against osmosis. Turgidity is very important to plants because this is what make the green parts of the plant "stand up" into the sunlight.

When plant cells are placed in concentrated sugar solutions they lose water by osmosis and they become "flaccid." This is the exact opposite of "turgid". The contents of the potato cells shrinks and pulls away from the cell wall. These cells are said to be plasmolysed.

When plant cells are placed in a solution which has exactly the same osmotic strength as the cells they are in a state between turgidity and flaccidity. We call this incipient plasmolysis. "Incipient" means "about to be".

Variables:

To create a fair test certain aspects of the experiment will have to be kept the same whilst one key variable is changed. I have chosen to vary the concentration of the sugar solution. This will give me a vary varied set of results from which I hope to make a decent conclusion. If any of the non-variables below are not kept constant it would mean it would not be a fair test. For instance if one of the potato chips was 1cm longer the surface area of the chip would be larger and there would therefore be more space for osmosis to occur. Doing all the tests at one temperature will control the temperature.
"X For the purpose of my experiment I am going to do all the experiments at room temperature.
"X To keep the water potential of the potato initially will be kept the same by using the same type of potato, which have been treated in the same way, e.g. have all been cut without being washed and peeled.
"X The mass of the potato is a dependent variable, and this means that it will be measured
throughout the experiment. I will measure the mass in grams. The potato chip will be
measured before it is put in the solution, and after. This will allow us to see whether
osmosis has taken place, and to what extent.
"X The volume of the solution that the potato chips are kept in must be fair. The must be
totally covered in the solution, and the amount of solution will be kept the same because
all the potato chips are the same size.
"X I am also going to use the same balance to weigh my potato chips. This is because the measurements may slightly vary between scales.

TABLE SHOWING THE DIFFERENT VARIABLES THAT WILL
BE CONSIDERED DURING THE EXPERIMENT

Variables Non-Variables
Solution concentration Surface area
Solution volume
Duration of experiment
Temperature
Solution
Weighing scales
Conditions
Preliminary Results

Concentration of solution Mass Before Mass After % Change in Mass

0.00m: 1st attempt 1.66 1.74 4.819277108
2nd attempt 1.58 1.66 5.063291139

0.25m: 1st attempt 1.7 1.62 -4.705882353
2nd attempt 2.06 2.07 0.485436893

0.50m: 1st attempt 1.69 1.62 -4.142011834
2nd attempt 1.78 1.67 -6.179775281

0.75: 1st attempt 1.76 1.6 -9.090909091
2nd attempt 1.71 1.56 -8.771929825

1.0m: 1st attempt 1.74 1.59 -8.620689655
2nd attempt 1.4 1.25 -10.71428571

Percentage change in accordance to the varying solutions

Concentration Average % change

0.00m 4.94128412
0.25m -2.11022273
0.5m -5.16089356
0.75m -8.93141946
1.0m -9.66748768

These preliminary results give me an overall impression on the change in mass gain or loss when placed in varying concentrations of sucrose solution.

Planned method:

A range of sucrose sugar solutions will be prepared with concentrations 0 molar, 0.25 molar, 0.5 molar, 0.75 molar and 1 molar. This will be done by adding varying amounts of distilled water to varying amounts of sucrose solution. Sections of potato will be cut using a scalpel and will be measured using a ruler. This part of the preparation must be done very accurately as a change in the surface area may allow more or less osmosis to occur. The mass of each chip will be measured as well so that more results can be obtained. Three chips will be placed in each test tube each time so that I can take an average for each tube. I will use 10 ml of each concentration of sugar solution and once in the test tubes they each will be labelled. The potato pieces will then be placed in the different test tubes and then left for 30 minutes. Then the potato pieces will be removed, the surface solution removed using paper towels and then they will be re-weighed. If I then have time afterwards I will repeat this experiment again as to obtain a second set of results. This will hopefully produce more accurate results from which I will be able to draw a more accurate conclusion.

Skill Area O: Obtaining evidence

Method:

1. I took two average sized ground potatoes and checked that they were both healthy and hard.

2. Using a standard kitchen knife I peeled the potatoes and cut each one into an even block approximately 7cm by 5cm by 4cm on a white tile.

3. Using a scalpel and ruler I cut the potato into ¡§chips¡¨ which were 5 cm long. I had to be very careful whilst cutting the potato as the scalpel is exceptionally sharp. I then had 15 chips.

4. Taking a test tube rack I placed 5 test tubes and then labelled them 0 molar, 0.25 molar, 0.5 molar, 0.75 molar and 1 molar.

5. Using a measuring cylinder I measured out different amounts of sucrose solution and distilled water which I then poured into the test tubes in a percentage ratio giving me the various molar concentrations.

6. I then weighed every potato chip on an electronic balance and recorded the weights.

7. I swiftly put 3 potato chips into each beaker and then started my stopwatch. 3 chips were used to create an average which gave me a better set of results and more accurate graphs.

8. Whilst waiting I set out some paper towels with which I was going to dry the paper and I drew up a basic table for my results.

9. After 30 minutes I drained out the solutions in the sink and placed all the chips on the paper towel in the order I had put them in the test tubes as to not confuse myself as to which chip came from which solution.

10. I dried each chip with the paper towel and then placed each one on the scales so that I could weigh them.

11. Each potato was measured accurately on the electronic scales and then the weights were recorded.

12. As I had time after doing the first set of results I redid the experiment under exactly the same conditions. This gave me secondary set of results which gave me a more accurate view on the changes.

Precautions:

"h As was stated in my planning section of the coursework, I had to keep all of the different non-variables the same, to make sure that none of them affected the results of the experiment in any way.
"h Whilst cutting the potato, extreme care and precision had to be taken with the scalpel as it is very sharp and could easily cause a serious wound.
"h The measurements for the solutions had to be perfect as to not change the out come of the experiment.
"h I had to ensure that every time I handled the potatoes my hands were clean and dry. This was to stop any kind of contamination and made sure that I did not pass on any extra water onto the potatMain Tables of Results for all Concentrations

0.00m concentration mass before (g) mass after (g) change in mass (g) % change in mass
1 1.46 1.52 0.06 4.109589041
2 1.64 1.75 0.11 6.707317073
3 1.72 1.85 0.13 7.558139535
4 1.64 1.89 0.25 15.24390244
5 1.63 1.85 0.22 13.49693252
6 1.75 1.95 0.2 11.42857143
average 1.64 1.801666667 0.161666667 9.757408672

0.25m concentration mass before (g) mass after (g) change in mass (g) % change in mass
1 1.56 1.46 -0.1 -6.4102
2 1.66 1.64 -0.02 -1.2048
3 1.6 1.61 0.01 0.625
4 1.51 1.15 -0.36 -23.841
5 1.63 1.68 0.05 3.06748
6 1.34 1.39 0.05 3.73134
average 1.55 1.48833 -0.0616 -4.0053

0.5m concentration mass before (g) mass after (g) change in mass (g) % change in mass
1 1.65 1.45 -0.2 -12.121
2 1.66 1.52 -0.14 -8.4337
3 1.88 1.71 -0.17 -9.0425
4 1.42 1.36 -0.06 -4.2253
5 1.66 1.51 -0.15 -9.0361
6 1.6 1.52 -0.08 -5
average 1.645 1.51166 -0.1333 -7.9764

0.75m concentration mass before (g) mass after (g) change in mass (g) % change in mass
1 1.64 1.36 -0.28 -17.073
2 1.49 1.34 -0.15 -10.067
3 1.87 1.74 -0.13 -6.9518
4 1.39 1.26 -0.13 -9.3525
5 1.8 1.63 -0.17 -9.4444
6 1.38 1.18 -0.2 -14.492
average 1.595 1.41833 -0.1766 -11.230

1.00m concentration mass before (g) mass after (g) change in mass (g) % change in mass
1 1.52 1.19 -0.33 -21.71
2 1.64 1.39 -0.25 -15.243
3 1.66 1.49 -0.17 -10.240
4 1.61 1.46 -0.15 -9.3167
5 1.66 1.49 -0.17 -10.240
6 1.56 1.42 -0.14 -8.9743
average 1.60833 1.4066 -0.2016 -12.621

This graph shown above gives the line of best fit for the percentage change in mass of the potato chips over the course of the thirty minute experiment. The graph is a curve that slopes downwards and does not go through the origin. Because the line is not straight and does not pass through the origin, it means that the percentage gain and loss in mass and concentration are not directly proportional. However, there is a pattern on my graph, and this is, as the concentration of the solution increases, the percentage change in mass decreases. The graph shows that the percentage gain and loss in inversely proportional to the concentration. The gradient does change in my graph. It gets less steep as X axis gets bigger. This is because the potato chip is becoming as flaccid as it possibly can, and so the change in mass of each molar concentration is becoming closer and closer together. From the line of best fit that has been added in, it can be seen that all of my points were very close to creating a perfectly smooth curve. This shows that my results are fairly reliable. My graph fits in with my prediction of the experiment graph.

It shows that the potato cells increase in mass in solutions with a high water concentration and decrease in mass in solutions with a low water concentration. When the concentration reaches above 0.75 M, there appears to be no further water loss, suggesting that the cell is fully plasmolysed. From the graph an estimate to the concentration of the potato cell can be made as 0.13 M, as this is the point where the potato is not increasing or decreasing in mass, this is known as the isotonic point. This is where no osmosis is taking place, both the potato and the solution have an identical molar concentration. The next point, 0.25 M looses approximately 4.0 %. This shows that the water potential of the salt solution in the beaker is weaker than that of the potato chip. The next, 0.50 M, looses approximately 8.0 % in mass. This shows that the salt solution has an even weaker water potential than 0.25 M and that osmosis took place. This is why the potato lost even more mass, and it shows that the water potential in the beaker is less than that of the potato chip. This pattern carries on through the graph, and even more mass is lost, as more water moves out of the potato into the solution. My results also match with my initial predictions.

This graph of the change in mass helps prove the point of complete plasmolysis, whereby the potato cannot expand and take in any more water. As you can see as the molar concentration increases the change in mass decreases. From right to left the first two points on the graph are very spread out indicating that there was a large change in the mass. This decreases throughout the increasing molar concentration until the change is minuscule (about 0.02g).

This graph above shows a clear indication that there was an overall decrease in mass during the experiment. At the point 0.00 M the line for after the experiment is above the line for before the experiment unlike any of the others. This is because the water potential of the sugar solution is higher than that of the potato chip.

Skill Area E: Evaluation

The experiment was very successful in my opinion. I obtained a large quantity of very accurate results from which I was able to create informative graphs. I think I took easily enough results for the amount of concentrations that I was using, and the time that I used for the experiment to last was enough to allow sufficient osmosis to occur. However if I was to repeat the experiment I might well increase the time of the result to allow more osmosis to happen and possibly find out the saturation point of the chips. The range of concentrations was adequate but I would possibly create more concentrations if I repeated the experiment so that I would have more varied results, i.e. 0.10m, 1.15m, 1.20m, and so on. This way would have allowed me to also find out the isotonic point far more accurately as the one that I estimated is very approximate.

The cutting of the potatoes was the most difficult part of the experiment as although I was recording my results by mass, it could well have affected the surface area and so the overall rate of osmosis. If I were to repeat the experiment I would have possibly found a machine to cut the potato as it would ensure that all potatoes would be the same weight and dimensions. As well as the potato I could have found a more accurate way to measure out the solutions and to determine the molar concentrations. Perhaps I could have used a burette. This would ensure that I have an accurate amount of fluid in each test tube. I could also weigh each chip on a more accurate scale, e.g. not to 0.00g but to 0.0000g.

There were not any out of the ordinary results, but some were not as close to the line as others. This may have been caused by human. When the potato chips were removed from the test tubes and dried I may well have dried some potatoes more thoroughly than others and so some would have more excess water, which would add to the mass. If the experiment was repeated I could find another way to dry the potatoes that would ensure that all were dried in the same way for the same time. However with all this said I think that the experiment was truly successful and I was very pleased with the complete comparison of my results with my initial prediction.