• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9

Investigating the effects of osmosis on potato cylinders.

Extracts from this document...


Tom Buckland Biology Coursework SC1 Investigating the effects of osmosis on potato cylinders Centre Number 10144 Candidate Number 1913 Background Science Osmosis is the passage of water from a region of high water concentration to a region of low water concentration through a semi-permeable membrane - Oxford English Dictionary Online Figure 1 - Showing the effects of osmosis In a high concentration of water the amount of solute (e.g. salt) is low. This is called a dilute solution. In a low concentration of water the amount of solute (e.g. salt) is high. This is called a concentrated solution. When a semi-permeable membrane the water divides two such solutions will move from the region of high concentration to the region of low concentration, until both sides are equal (have reached equilibrium). Osmosis occurs across a semi-permeable membrane whenever there is a difference between the water concentrations on the two sides of the membrane when this happens, cells will either become turgid if water flows into them, or plasmolysed if water flows out. Figure 2 - Showing Equilibrium This can be seen in living cells. The cell membrane in cells is semi-permeable and the vacuole contains a sugar/salt solution. So when a cell is placed in distilled water (region of high water concentration), water will move across the semi-permeable membrane into the cell (region of lower water concentration), through osmosis, making the cell swell. ...read more.


* Calliper * Measuring cylinder * Distilled water * Cutting tool * White tile Safety There are many potential hazards in this investigation that must be taken into account. They are outlined in the table below - Hazard Solution Cutting someone with a razor / knife blade Use caution when using the blades. Cut away from yourself and other people. First aid should be available should any incident occur. Breaking any glass objects (Boiling tubes etc) Inform the member off staff then sweep up the glass and place it a broken glass container (if available) or in the bin. Getting any solution in eyes Wear safety goggles at all times during the experiment. Should any solution enter someone's eye, the eye should be washed immediately. Method With the changes from my preliminary experiment outlined in my plan, I shall use the following method in my final investigation - Set Up * Set up six boiling tubes in a boiling tube rack * Label them with the concentration of solution they will contain * In five of the tubes place 35ml of each of the chosen solutions * In the remaining tube place 35ml of distilled water * Select six approximately equal length cylinders of potato * Allocate each cylinder to a concentration of solution * Measure each cylinder individually (noting the length) * Then weigh each of the cylinders (noting the mass) ...read more.


2.92g - 0.95g 47mm 44mm - 3mm 0.5 mol/ dm-3 3.92g 2.75g - 1.17g 45mm 41mm - 4mm 0.6 mol/dm-3 4.18g 2.77g - 1.41g 46mm 39mm - 7mm 0.8 mol/dm-3 3.92g 2.39g - 1.53g 46mm 38mm - 8mm 1 mol/ dm-3 4.22g 2.67g - 1.55g 47mm 39mm - 8mm Experiment 3 Concentration of salt solution Mass before experiment Mass after experiment Change in mass Length before experiment Length after experiment Change in length 0 mol/dm-3 4.27g 4.82g + 0.55g 48mm 52mm + 4mm 0.2 mol/dm-3 4.36g 4.00g - 0.36g 49mm 48mm - 1mm 0.4 mol/dm-3 4.38g 3.37g - 1.01g 49mm 45mm - 4mm 0.5 mol/ dm-3 4.44g 3.19g - 1.25g 50mm 44mm - 6mm 0.6 mol/dm-3 4.19g 2.81g - 1.38g 48mm 41mm - 7mm 0.8 mol/dm-3 4.53g 3.10g - 1.43g 50mm 41mm - 9mm 1 mol/ dm-3 4.44g 2.81g - 1.63g 50mm 40mm - 10mm Appendix C - Glossary Equilibrium Isotonic is when a cell has the osmotic pressure to that of the surrounding medium. Osmosis is the passage of water from a region of high water concentration to a region of low water concentration through a semi-permeable membrane. Plasmolysed is when a cell has suffered from plasmolysis (see below). Plasmolysis is the loss of water by osmosis from a plant cell to the extent that the cytoplasm shrinks away from the cell wall. This happens when the cell is placed in a solution that has a higher solute concentration than that of the cell sap. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Life Processes & Cells section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Life Processes & Cells essays

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

    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

  2. Investigating the effect of different concentration of glucose (C H O ) and salt ...

    which cannot expand a certain point. Besides that, I am expecting that osmosis would have a better impact on the potato chip when the external solution is sodium chloride than if it would have been glucose. Each mole of NaCl dissociates into one mole of Na and one mole od Cl .

  1. Stephen Blackpool: The Pathetic Figure.

    Dickens creates the individual like Stephen to show the problems of the workers. Stephen is generous and unselfish. He doesn't care about the reward that he will receive if he tells his master the truth about the strike. On the contrary, he cares for his fellow workers' feelings and doesn't want them to be in trouble.

  2. A Sc1 Investigation into the effect of Concentration on Osmosis:

    Plant cells should only just be turgid (B) and balanced between plasmolysis and a fully turgid plant, but, in nature, cells fluctuate between being flaccid and fully turgid. Therefore, if the plant cells can plasmolysis or become fully turgid then there must be a change in mass because the cells are changing size (e.g.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work