• 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
  10. 10
  11. 11
  12. 12
  13. 13
  14. 14

To find the osmotic pressure of potato cells.

Extracts from this document...


Osmosis Aim To find the osmotic pressure of potato cells. I can find this out, when there is no net movement (change of mass in potato cylinder) when placed in different concentrations of sugar solution. Background Information Arrangement and movement of particles in solids, liquids and gases. Solids have strong forces of attraction between molecules. The molecules are held in fixed positions, in a very regular lattice arrangement. They keep a definite shape and volume. Solids can't be compressed because the molecules are very close together. Solids are generally very dense. Liquids have some force of attraction between molecules. The molecules are free to move. Liquids don't keep a definite shape. The molecules are constantly moving in random motion. Liquids can't be compressed because the molecules are already packed closely together; liquids are quite dense. Gases do not have a force of attraction between their molecules. The molecules are free to move. Gases don't keep a definite shape or volume. The molecules are constantly moving at random. Gases can be compressed and have very low densities. Diffusion This is the movement of a substance from a region where it is at a high concentration to a region of lower concentration. i.e. down a concentration gradient. Particles that make up a gas or a liquid always move around. If there is a lot of one type in one place and few of them in another, then particles move to where there are fewer. Eventually the particles will be spread about evenly. They move from where there is a high concentration to where there is a low concentration. This is diffusion. Osmosis Osmosis is a special type diffusion, it is the movement of water molecules from a region of high water concentration (a dilute solution) to a region of low water concentration (concentrated solution) through a semi-permeable membrane. A semi-permeable membrane is a very thin sheet of material. ...read more.


surface area of potato cylinder. * Concentration of the sugar solution Output variables * Change in the weight of potato pieces The importance of keeping the variable the same is vital, because it might effect our results. Also I'm going to explain whys its important to keep this variables and explain how this would effect my set of results. * Temperature = the temperature must be kept constant, because If I increases the temperature, it enabling the water particles to move faster, which makes the osmosis process faster, which will effect the overall result. * The volume of the solution should be kept the, because the higher the volume, the more water, which makes the solution dilute on the other hand the less volume, the less volume which makes the potato's to have more solution * If the length if times are not kept the same, then the water molecules will have more or less, time then the other experiment, therefore increases the volume of the potatoes. * If the weights are not the same the same then this would mean that the number of particles in the potatoes are not equal and therefore the concentrations inside the potatoes might not be the same. This would lead to different amount of osmosis taking place, as the starting concentrations need to be the same inside the potatoes to allow the solution concentrations to be varied * If the potato pieces are not the same exact shape this will mean that the surface area of the pieces is not equal and this would lead to a different of osmosis taking place with more occurring where the surface area is larger. The starch molecules in potato are bigger and can't go through the semi permeable membrane and to the pure water solution. But the water molecules are much smaller and can go through and swell the potato. ...read more.


As well as the potato I could have found a more accurate way to measure out the solutions and to determine the molar concentrations There were not any out of the ordinary results, but some were not as close to the line as others. When the potato chips were removed from the test tubes and dried I may well have dried some potatoes more thoroughly than others and so some would have more excess water, which would add to the mass. If the experiment was repeated I could find another way to dry the potatoes that would ensure that all were dried in the same way for the same time. However with all this said I think that the experiment was truly successful and I was very pleased with the complete comparison of my results with my initial prediction. If we were to this experiment again we would have larger pieces of potatoes to get a more precise measurement by using s ruler or we would need a microscopic measurements (a length smaller than a mm) to get an accurate size so that all the length are the same. we would do proper repeats rather than putting three in one boiling tube and counting it as a three repeat. I would also get a weight measurer that is more effective (as in measures very light weigh). After comparing my graphs to a couple of graph's graphs, I found out that we had the corrected and very reliable graph drawn, with a lines of best fit. This ensures me that my sets of results were very much corrected. On my graph I have drawn a straight line form my correct set of results. I have also seen others 's group's graphs and I have figured that I have drawn the correct line on the graph. I believe we gained accurate and sufficient enough results, shown on our graph and tables that concludes the experiment, and to prove our hypothesis. My final results were very reliable, due to the precautions I took to make this a fair test. ...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

    How does the concentration of a sucrose solution affect the rate of Osmosis in ...

    5 star(s)

    Here are the results of the trial experiments: Percentage of sucrose in solution Mass of potato before (test 1) in grams Mass of potato after (test 1) in grams Mass of potato before (test 2) in grams Mass of potato after (test 2)

  2. Marked by a teacher

    To determine the water potential of a potato tuber cell using varying salt solution.

    5 star(s)

    4 Time I think the time the potato pieces were left in the salt solution was not that sufficient because I do not feel that they were kept in for a long enough time for enough of the effect of osmosis to have occurred.

  1. Marked by a teacher

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

    5 star(s)

    Osmosis causes this. As water goes into the cell, it causes the cell to swell up. As there is more water on the outside of the cell than on the inside, it creates a high pressure upon the outside that forces the water into the cell where the pressure is

  2. Marked by a teacher

    Investigating the effect of sucrose concentration on osmosis in potato cells

    4 star(s)

    I predict this because osmosis happens with the concentration gradient, that is, from a high water potential to a low water potential. So when the sucrose concentration is lowest, the water potential is highest, higher than the water potential inside the potato cells, so water will move into the potato by osmosis, increasing its mass.

  1. Estimate the concentration of the cytoplasm of potato cells.

    In a more dilute solution, where there is more water present I predict that there will be a nett gain of water. Preliminary Experiment The reason that I conducted a preliminary investigation was so that I could find out the best method in which I should conduct my main experiment

  2. Osmosis, What is the effect of sucrose concentration on the rate of osmosis in ...

    I will assume that the concentration is 0.5M. The two concentrations mentioned above show the greatest water potential gradient and therefore the fastest rates of osmosis. From looking at the pilot test results, I can see that the greatest mass loss took place when the potatoes were in a sucrose concentration of 1.0M.

  1. Aim: To find out the effect of altering the concentration of sugar solution on ...

    To begin my experiment, I will use the cork borer to make up the same size chips from the potato. After this, I will weigh each potato chip on a scale so that each is of similar size and weight.

  2. Investigating the cellular water potential of potato cells.

    be assured that the diameter of the samples will always be the same if I use the same cork borer each time. However, with the cuboids, it is much harder to regiment the size and shape as it is almost all done by eye.

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