The time the potato chip is left in the solution must be kept the same in each
experiment. This is because more or less solution may be absorbed depending on time. I am going to keep each potato chip in each solution for 1 hour, in a boiling tube.
The surface area of the potato chips will be kept the same by having all the chips the same size. This must be kept the same because the amount of surface area exposed to the solution may effect the rate of osmosis. The thickness of the chip will already be the same, so I will cut the length so that each chip is 3mm long.
To make the mass readings more fair, I will take each chip of the solution, roll all the surfaces gently on a paper towel, (2 seconds on each surface), to remove all excess solution, and I must not squeeze the chip.
Prediction
I predict that the higher the concentration of sugar solution the more water will move out of the potato chip. We know that osmosis the flow of in water a solution through a membrane while the other constituents are blocked and unable to pass through the membrane Experimentation is necessary to determine which membranes permit selective flow, or osmosis, because not all membranes act in this way. Many membranes allow all or none of the constituents of a solution to pass through; only a few allow a selective flow. As the potato is a plant cell, it contains a vacuole and a cytoplasm. The cell membrane is also partially permeable i.e. it lets some substances in but not all substances. This means that water paeticalscan diffuse into cells by osmosis if the cells are surrounded by a weak solution. (Osmosis is the movement of water molecules from a high area of water potential to an area of low water potential through a selectively permeable membrane. If the cells are surrounded by a stronger solution, e.g. salt water, the cells may loose water by osmosis. (See in diagram).
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 to ensure safety; the boiling tubes will be kept in beakers so that they can not be knocked over. The potato chips will be cut on a white tile with a scalpel so that no one will be cut. 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
Diagram
Method
- Draw up a table of result and get all equipment
- Using a cork cuter I cut cylinders out of the potato
- Using a scalpel and ruler cut the cylinders down to the same size (3mm long). I had to be very careful whilst cutting the potato as the scalpel is exceptionally sharp.
- Taking a test tube rack place 5 test tubes and then labell them 1, 2, 3, 4 and 5
- Use the glass rod to stir the sugar and 30ml of distilled water which should be in the test tubes, along with the potato chip to make the experiment work better.
- Weigh every potato chip on a top pan balance and record the weights in a table.
- All 5 potato tubes will then be placed in individual test tubes, which are filled with different amounts of sugar. The first potato chip will be placed in distilled water which has no sugar. The other 4 potato tubes are placed in different amounts sugar which is 0.2, 0.4, 0.6, 0.8g.I will weigh each one use the weigh balance.
- Leave the potato chips for 1 hour in the test tubes.
- When 1 hour is up, take the potato chips out and use a paper towel to absorb the excess sugar/distilled water which will be dripping off it. If this isn’t done it would affect the results by making the potato chips heavier when coming to weigh it.
- The sensitive balance will be used to weigh all 5 potato tubes. Which I will record the results.
- Repeat the experiment again another two time
Preliminary Results
From my preliminary result I coming to change the solution indent of just guess how much sugar to put. I will measure out 0.2, 0.4, 0.6, and 0.8g to get a better result. I could have a number of experiments going on at once so that I save time. I will remove any excess water by rolling the chip on a paper towel, keeping each surface on the towel for 2 seconds, making sure that I do not squeeze the chip so that my results are fair. The more results I have the more reliable my graph will be, so when I come to do my actual experiment I will repeat it 3 times. One result may not be accurate because of human error, so to eliminate all possibilities of inaccuracy I will repeat it. I must also make some labels to label my test tubes with so that the test tubes do not get mixed up.
Obtaining evidence
Table of results
In the table below, it shows the ‘solution’ columns, which are the 5different types of solutions. The ‘number of test’ column, which shows the number of tests that, took place. The temperature when I was doing my actual results was 27°C.
First time
Second time
Third time
Table for all 0.20g solution
Analysis
What I have found out is that the higher the concentration of sucrose the more flaccid the potato becomes. This is because the water inside the potato is moving from a higher concentration to a lower concentration. In other words the water inside the potato is leaving it, as it is passing from a weak concentration to a strong concentration. Making it smaller and lighter. Where as with water as the solution, the potato piece gained weight. This is due to osmosis, where water passes from weak solutions to strong solutions across a semi-permeable membrane, such as a cell membrane. I think that the results of the experiment agree with my prediction. I am also going to use the same balance to weigh my potato chips. This is because the measurements may slightly vary between scales. 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 potato.
Evaluation
I think that the method used was fairly accurate, as considering the equipment that I had used I had made the best possible outcome for my results obtained.
My method was good; it was easy to carry out and causes no hassles or complications with the investigation. Using more types of solutions would have helped us obtain better results, and more accurate results; so that I can make sure the results are totally correct. When looking at my results I can conclude that they are good enough to support a firm conclusion, as my results were as what I had predicted. Improvements for this investigation would be that I should have repeated the experiment more times, making the results more accurate. I think this experiment turned out to be very successful, and I’m very please with my results. I was very pleased with the complete comparison of my results with my initial prediction.
