An investigation into the effect of Osmosis on potato chips
... with concentrations from 0.2 M to 1.0 M, by adding varying amounts of water from the beaker. · This is done using a pipette, for example to get 0.4 M of salt solution I measured 2cm³ of salt solution into the pipette, and 3cm³ of water (0.6 M) and transferred the concentrations into one of the six test tubes. The total amount of volume of the two solutions in each test tube will be 5cm³. · Each Potato slice will be left in it’s test tube with it’s concentrations for 20 minutes. · After the 20 minutes, each Potato slice will be taken out of it’s test tube and weighed by the electronic scale. Each Potato slice will also be measured in length. Both the mass and lengths of the Potato’s will be recorded in a table. · A percentage change in the mass and length will be worked out. · After the 20 minutes, measure the final mass and length of each Potato slice and work out the change in mass and length. Then work out the percentage change by using the formula: % Change = change in mass/length Original mass/length · Repeat the experiment and procedure three times · Work out the average percentage change in mass and length, and record the results in a table. · Show the percentage change in mass and length of the different salt solution concentrations in a graph Table to show how concentrations were mixed: Volume of water (cm3) Volume of 1Molar Salt solution (cm3) Concentration of Salt solution (M) 5 0 0.0 4 1 0.2 3 2 0.4 2 3 0.6 1 4 0.8 0 5 1.0 Safety: · Keep hands well away from the sharp end of the scalpel, as it could cut you. · Use the syringe to suck up the salt solution and water carefully to avoid spillage. · Push stools in to avoid tripping up with apparatus in your hand. Fair Test: To ensure that the experiment is fair, I will keep the volume of solution in the test tubes the same, 5cm³. The time that the potatoes are left in the test tubes will also be the same, 20 minutes, and I will keep the test tubes in the same temperatures, (room temperature). Variables: · Input variable; the variable that I am going to change is: 1) The concentration of the salt solution 2) The concentration of the water By varying the volumes of both solutions we can see what effect they have on the potato in relationship with osmosis. · Output variable; the variable that I am going to measure. This will be the mass and length of each Potato chip before and after the experiment. This will help me to see the difference in mass and length, so I can work out if they have gained or lost mass and length. · Controlled variable; the variable that will be kept the same. This will be the volume of the total amount of solution put into each test tube, 5cm³. This will ensure that the experiment is fair. Results: Concentration of Salt solution (M) Repeat number Initial mass of potato (g) Final mass of potato (g) Initial length of potato (mm) Final length of potato (mm) (%)Change in Mass (%)Change in length 0.0 1 2.2 2.4 30 32 9.09 6.67 2 2.5 2.7 30 33 8.00 10 3 2.3 2.5 30 33 8.70 10 0.2 1 2.4 2.3 30 30 -4.17 0 2 2.2 2.1 30 30 -4.55 0 3 2.3 2.2 30 30 -4.35 0 0.4 1 2.6 2.4 30 29 -7.69 -3.33 2 2.5 2.2 30 29 -12.00 -3.33 3 2.5 2.2 30 29 -12.00 -3.33 0.6 1 2.4 2.0 30 28 -16.67 -6.67 2 2.2 1.8 30 28 -18.18 -6.67 3 2.5 2.1 30 29 -16.00 -3.33 0.8 1 2.5 2.0 30 28 -20.00 -6.67 2 2.7 2.3 30 28 -14.81 -6.67 3 2.6 2.1 30 28 -19.23 -6.67 1.0 1 2.7 2.1 30 28 -22.22 -6.67 2 2.6 1.9 30 27 -26.92 -10 3 2.4 1.8 30 27 -25.00 -10 Concentration of Salt solution (M) Average (%) change in mass Average (%) Change in length 0.0 8.60 8.89 0.2 -4.36 0 0.4 -10.56 -3.33 0.6 -16.95 -5.56 0.8 -18.01 -6.67 1.0 -24.71 -8.89 Conclusion My results show that the lower the concentration of salt solution the potato is placed in, the more mass and length it gains. The higher the concentration of salt solution that the potato is placed in, the more mass and length it loses. The graph of the average % change in mass has a line of best fit, which is descending from 0.0 M of salt solution, showing that this solution had the highest % change in mass of all the concentrations. Similarly the graph of average % change in length has a descending line of best fit showing me that the 0.0 M of salt solution gained the most length. According to my results and graph, my hypothesis was correct. I rightly predicted that the Potato chip in the most concentration of salt solution lost the most mass and length, and the Potato chip in the least concentration of salt solution gained the most mass and length. My results support this because the 0.0 M of Salt solution gained the most mass and length and the 1.0 M of salt solution lost the most mass and length. This is because of Osmosis. Osmosis is the movement of water molecules from a dilute to a more concentrated solution. When the Potato is put in a big concentration of salt solution and a little concentration of water, the water molecules move from the dilute solution (Potato) to the more concentrated solution (salt solution). This means it will lose mass, and length because it is losing some water molecules. This is why the 1.0 Molar of salt solution lost the most mass and length. When the Potato is put in a small concentration of salt solution a big concentration of water, the water molecules move from the dilute solution (water) to a more concentrated solution (Potato), so the potato will gain mass and length, because it is gaining water molecules as a result of osmosis. This is why the 1.0 M of water has gained the most mass and length as it a lot of water which is a dilute solution so more water will move from the water to the more concentrated potato. As a result of my potato cell investigation I can make a general pattern on osmosis; The greater the concentration of water in the external solution, the greater the amount of water that enters the cell by osmosis. The smaller the concentration of water in the external solution the greater the amount of water that leaves the cell. Evaluation My experiment was fair because I used the three variables in the experiment. The input variable was that I changed the concentration of the salt solution and the concentration of the water that the potato was placed in. The Output variable was the measurement of the potato chips in mass and leng...