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Investigating Osmosis

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BIOLOGY COURSEWORK INVESTIGATING OSMOSIS A. PLAN Aim of investigation: To investigate the effect of different concentrations of sucrose on osmosis in potato chips. Definition of osmosis: Movement of water molecules from a dilute to concentrated solution across a partially permeable membrane. Independent variable: Concentration of sucrose solution. Range of values (details of dilutions): Molarity of solution/M Amount of sucrose solution/cm� Amount of water/cm� 1 10 0 0.8 8 2 0.6 6 4 0.4 4 6 0.2 2 8 0 0 10 Dependant variable: The mass (grams) and length (mm) --> Size of chip The length will be measured accurately with a ruler, rounded to the nearest millimetre. The mass will be measured on an electronic balance to the nearest 0.5g. Before these steps we must blot first to remove the sucrose solution from the outside of the chip as if it remains then we won't get the required reading (as the chip will weigh more than it actually is). How to control the variables: Variable How to control and why Temperature This will be kept constant by using a water bath and will be using a thermometer to ensure that the temperate is the same for all experiments. If the temperature changes during different experiments then the rate of osmosis will vary producing unreliable results. ...read more.


B. RESULTS BEFORE: Concentration/M Chip 1/g Chip 2/g Chip 3/g 0.00 4.45 4.12 4.21 0.25 4.27 4.25 4.15 0.50 4.21 4.30 4.45 0.75 4.22 4.28 4.11 1.00 4.24 4.29 4.39 AFTER: Concentration/M Chip 1/g Chip 2/g Chip 3/g 0.00 4.92 4.57 4.71 0.25 4.31 4.29 4.51 0.50 3.78 3.94 4.11 0.75 3.68 3.70 3.61 1.00 3.72 3.50 3.62 % Change in mass analysis: (Final Mass - starting mass) / Starting mass x 100% Concentration/M Chip 1/% Chip 2/% Chip 3/% 0.00 10.6 10.9 11.9 0.25 0.937 0.941 8.67 0.50 -10.2 -8.37 -7.64 0.75 -12.8 -13.6 -12.2 1.00 -12.3 -18.4 -17.5 Note: All % change figures are rounded to 3 significant figures. Average value comparison: Addition of total values wishing to average / Number of values: Concentration/M Average Chip/g Before 0.00 4.26 0.25 4.22 0.50 4.32 0.75 4.20 1.00 4.31 After 0.00 4.73 0.25 4.37 0.50 3.94 0.75 3.66 1.00 3.61 C. ANALYSIS By looking at the % change in mass table, we can state that as the sucrose solution concentration increases, the % change in mass decreases. Here is a rough draft of the graph which will appear later: We can say that there is an inverse relationship between the concentration of sucrose and the % change in mass. This is because at 0M there is a positive % change in mass and as we further increase the concentration we see a decrease in % change with most concentrations having a negative % change in mass. ...read more.


Yes, we can see where the line is able to cross the "x" axis. However this is proven to be inaccurate because I am only assuming using the line of best fit and also there is no data for that point. Further work which could add extra information? There is a lot of further work we could do. We could have done more concentration levels within our range which would give us a more broad view and would increase reliability of our present results, we could use salt solution instead of sucrose solution to see if the same applies with other substances, we could increase the size of the chips to see if rate of osmosis correlates with size, we could see the change in length instead of the change in mass to see if there is a relationship between length and rate of osmosis, we could leave the chips for a different period of time and we could also use a much wider range for our range of values which again provides us with a wider variety of results from which we can compare to get more accuracy. We could benefit hugely by doing these additional theories because we would have a much better understanding of osmosis, and also we could compare what effects these changes would have on osmosis and finally we can understand better of which conditions and limitations are best for optimum osmosis. - 8 - ...read more.

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    Investigating the effect of Sucrose Concentration on the Rate of Osmosis in Potato Chips.

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    This causes the potato to increase in mass and become turgid. This concentration gradient therefore causes water molecules to osmose down the concentration gradient, across the partially permeable membrane and into the plant cells (those of the potato chips). This was the case for when the solution concentrations were 0.0mol/litre

  2. Osmosis is defined as 'the movement of water molecules from an area of high ...

    I could have also used a machine to cut the potato chips. I could also weigh each chip on a digital and more accurate scale, e.g. not to 0.00 but to 0.0000g. There was one main anomalous result, this is highlighted in red and is two sizes bigger (tube I),

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