• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Investigate the effects of varying sugar concentration on the amount of osmotic activity between the solution and the potato tubes cut to a given size.

Extracts from this document...


Aim: To investigate the effects of varying sugar concentration on the amount of osmotic activity between the solution and the potato tubes cut to a given size. Hypothesis: Osmosis is defined as the net movement of water molecules from a region in which they are highly concentrated to a region in which they are less concentrated. This movement takes place across a partially permeable membrane e.g. a cell wall. This means that the cell wall will let 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, in our case (when both the potato cell and the solution have the same amount of sugar solution concentration,) Method: To make it a fair test certain aspects of the experiment had to been kept the same while only one variable was changed. The variable was the concentration of the sugar solution. This gives us a very varied set of results from which we could make a conclusion. If any of the non-variables below were not kept constant it would mean it would not be a fair experiment. For instance if one of the potato tubes was 1cm longer than all the other potato tubes this would therefore mean more space for osmosis to occur. ...read more.


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. I also repeated the experiment once again; this gave me the most accurate results I could have hoped for. !!!!!!!!!!!!!"����"$$$$$$$$$$$$$$%%%%%%%%%%%%^&^&&&&&&&&&&&&*( Conclusion: When the concentration reaches , there appears to be no further water loss or gain, suggesting that the cell is fully plasmolysed. From the graph an estimate to the concentration of the potato cell can be made as 0.28M, 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 concentration. The time I used to test the potato chips was plenty of time to allow sufficient osmosis to occur as. However if I was to repeat this investigation I might decrease the time of the experiment because I don't think it would have taken 1 week, as I believe osmosis would occur within a couple of hours. ...read more.


I could have also found a more accurate way to measure out 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. 0.000g not 0.00g. 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. 0.1M, 0.2M, 0.3M, 0.4, 0.5, 0.6 etc. 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. I think I took just enough results but if I were to do this investigation again I would certainly take more so that I would have a greater chance of obtaining more reliable ones. There were no out of the ordinary results, but some were not as close to the lines as others. This may have been caused by human mistake. When the potato chips were removed from the flat dishes and dried I may well have dried some more thoroughly than others and so some would have more excess water, which would add mass. If the experiment was repeated I could find another way to dry the potatoes, which would ensure that all were dried in the same way for the same amount of time. ...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. Marked by a teacher

    To investigate how varying the concentration of sucrose solutions affects the rate of osmosis ...

    3 star(s)

    Then using the scalpel, I will cut off both ends of each potato cylinder. I will then measure the lengths of each potato cylinder and cut it accordingly so that all of them will be 5.00cm in length. Using a tissue paper, I will remove any waste left on the cylinders.

  2. Potato and Osmosis Investigation Skill Area P: Planning Aim: To Investigate the Effect of ...

    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.

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

    I think I took enough results for the amount of moralities that I was given, and the time restrictions that I had to follow, (1h20 mins). The range was big enough, but to fill in the gaps in my graph, I could have taken results of more moralities, i.e.

  2. Osmosis, Aim: To investigate the effect of varying concentration of a certain sugar solution ...

    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.

  1. Aim To investigate the effect of varying concentration of a certain sugar solution (sucrose) ...

    x15 2. Dry the potatoes with paper towels and then weigh each potato to get the original mass. 3. Create different solute concentrations: * Distilled water * 25% sucroce (12.5mL) and 75% water (37.5mL) * 50% sucroce (25mL) and 50% water (25mL) * 75% sucroce (37.5mL) and 25% water (12.5mL)

  2. To investigate the effect of varying concentration of different sugar solutions on the amount ...

    There is no weight change in the potato. A plasmolysed cell is one where water has moved out from the cell and the cell has lost weight. The cell is flaccid. Variables which may affect the outcome of my experiment In order to make this experiment a fair test I

  1. Investigate the effects of varying concentration of sucrose solutions on the amount of osmotic ...

    This is because the measurements may slightly vary between scales. * Number of tests - each potato tube in each different sucrose solution should be tested 3 times (a total of 15 tests) in order to obtain an average and more accurate results.

  2. Investigate the effect of varying concentration of a certain sugar solution on the amount ...

    These cells are called plasmolysed cells. 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. These cells can be called as incipient plasmolysis.

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