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

To investigate how osmosis in potatoes is affected by varying the concentration of a salt solution.

Extracts from this document...


Investigation into the effect of Concentration on the Rate of Osmosis Aim: To investigate how osmosis in potatoes is affected by varying the concentration of a salt solution. Introduction: Osmosis is the movement of water molecules between selectively permeable membranes. It takes place in all cells, at the surface of the organism. In order for osmosis to take place, a concentration gradient is needed on each side of the cell membrane. The water molecules move across the membrane during osmosis and always travel from a higher concentration to a lower concentration. If a potato chip is put into water, where the number of particles inside the potato is less than that compared to the number of particles outside the potato, the mass of the potato should increase, due to the fact that the water would be able to travel through it; the concentration outside the potato is less than that of the concentration inside the potato. However, if the water concentration was to be changed, i.e. salt was added, the concentration of the water would increase and the solution would become stronger than that of the potato, then the water molecules would be able to move out, rather than in, and so the potato would decrease in mass. ...read more.


This occurs when a concentration gradient is established. The water molecules which move across the membrane during osmosis always travel from the higher to the lower concentration. So if we leave a potato chip in distilled water, where the number of particles (water molecules) in the potato is less than the solution outside of the potato than that inside the potato, water should travel into it and its mass should increase. Now if the distilled water were replaced with 0.5 molar (0.5M) salt solution, the concentration of water in the potato would become higher than that of the solution to which it is being compared and therefore, water molecules would move out of the potato and its mass would decrease. When an identical potato chip is then placed in a weak solution of 0.5M, the concentration of water would be higher in the potato chip and therefore the rate of water loss in the potato chip would be greater than the rate of water entering the potato chip and therefore the cells in the potato chip would become flaccid (when the contents of the cell pull away from the cell wall, the process is called plasmolysis and the cells have become plasmolysed) this is because of osmosis as the concentration gradient has tried to be lessened. ...read more.


* Do not distract others while they conduct their experiment. Preliminary Experiment: To ensure that my experiment would be carried out without any problems and inconveniences, I conducted a preliminary experiment prior to my actual experiment. Concentration (Mole, M) Mass of Chip 1 Mass of Chip 2 Mass of Chip 3 Average mass Change in mass (Gram, g) (Gram, g) (Gram, g) (Gram, g) Before After Before After Before After Before After g % 0 1.02 1.2 1.11 1.33 0.99 1.35 1.04 1.29 0.25 24.01 0.5 1.2 1.19 1.15 1.13 0.98 0.95 1.11 1.09 -0.02 -1.08 1 1.09 0.98 1.03 0.99 1.10 0.92 1.07 0.96 -0.11 -10.28 1.5 0.99 0.81 1.03 0.85 1.10 0.82 1.04 0.83 -0.21 -20.19 2 1.04 0.70 1.00 0.65 0.98 0.59 1.00 0.65 -0.35 -0.35 I will now plot the results I have on a piece of graph paper. This will enable me to read the results more clearly and to draw a definite conclusion as to whether my prediction was correct or not. I will also be able to see which changes I need to make, where I will have an anomalous result, which I will be able to change during the actual experiment. Graph (on next page): Analysis of Preliminary results: As evident by the graph, my prediction has been proved; as the concentration gradient increases the amount of osmosis will also increase. ?? ?? ?? ?? - 1 - Naaila Haq 10g1 Biology Coursework-Osmosis ...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 determine the water potential of a potato tuber cell using varying salt solution.

    5 star(s)

    If the potato cells are kept in different amount of solutions for example, one is kept in 5ml of 0.0 mole solution and the other in 20ml of 0.6 mole concentration the 5 ml will still not gain as much mass as there are simply not as many molecules.

  2. Marked by a teacher

    How does the concentration of salt solution affect osmosis in potatoes?

    4 star(s)

    The higher the concentration of salt solution, the more the potato chip will lose its weight, width and length. Because water molecules have kinetic energy, they are constantly moving around in gaseous or liquid form, moving randomly from one place or another.

  1. Marked by a teacher

    An experiment to investigate how the effect of varying concentrations of salt solutions play ...

    4 star(s)

    First of all I believe I should have obtained more results and with those results should have gained an average. Therefore for my final experiment for each molarity I shall have 3 potato cylinders and by having those results I can gain an average.

  2. Marked by a teacher

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

    3 star(s)

    Using my graphs, I calculated the molarity of cell sap. I did this by denoting the point on the x-axis where the graphs for change in mass and change in length intersected. At this point, the potato cylinders did not gain neither mass nor length.

  1. Osmosis Experiment Aim: To investigate the factors which affect osmosis in potatoes and ...

    * I will place each potato piece in a galli pot. Each galli pot will have 30ml of solution in it of varying sugar concentrations. The sugar solution I will be using is 340g/l sugar solution, which is equal to 1 molar, which I will be mixing with distilled water to create different concentrations.

  2. Lab Research Paper. Just a Pinch of Salt and a Dash of Bacteria: the ...

    Salt Concentration Zone of Inhibition (in mm) Salt Concentration Zone of Inhibition (in mm) 0% 13 0% 11 0% 11 1% 10 1% 10 1% 11 3.5% 10 3.5% 11 3.5% 8 7% 16 7% 9 7% 13 15% 12 15% 12 15% 14 25% 14 25% 10 25% 10 Figure 2.3: B.

  1. Discover what effect water with different NaCl concentrations have on potatoes, and find out ...

    The line could level off in this experiment if I have got the percentage change wrong, and it reaches the levelling off point earlier than expected and therefore has a much steeper gradient. I may also have got the point at which it levels off wrong.

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

    And that is why I am predicting that the weight of the potato in this experiment should be decreased by only a fraction. The 0.6 molar solution of sucrose, I think, should make a big difference now, noting that it should be a large difference between the two concentration gradients.

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