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

To find the isotonic level of a potato.

Extracts from this document...


Aim: Our aim is to find the isotonic level of a potato. Scientific explanation of what would happen: Osmosis is defined as the movement of water molecules from an area of high water concentration to an area of low water concentration, across a semi-permeable membrane. In a high concentration of water the amount of solute (e.g. sugar) is low. This could be called a weak or dilute solution. In a low concentration of water the amount of solute (e.g. sugar) is high. This could be called a strong or concentrated solution. When two such solutions are divided by a semi-permeable membrane the water will move from the area of high concentration to the area of low concentration, until both sides are equal (have reached isotonic level). Isotonic is the net movement of water from an area of high water concentration to an area of low water concentration. Preliminary Work: For my preliminary work, we carried out an experiment that clearly explained to me the process of the movement of water molecules called osmosis. The diagram below will show the scientific explanation that was mentioned earlier. As you can see, the visking tube containing pure H O has decreased in mass due to its contents moving into the beaker therefore the visking tube containing 25% sugar solution has increased in size due to the contents of the beaker has transferred to the tubing. ...read more.


3: Stop the evaporation of any of the sugar solution. This is because if the sugar solution evaporates past the level of the potato, then the potato sample will have less surface area in the solution so this would make osmosis happen much slower. To stop any solution evaporating a cork lid can be placed on top of the test tube. 4: Accurate amount of sugar solution: More Bathing solution may affect the rate of solution. To make the amount of solution placed in the test tube as accurate as possible a syringe will be used to measure out the exact amount needed. 5: Contamination: As each test tube is filled up with the different sugar solutions the syringe which would measure the amount of solution placed in the test tube may become contaminated with different substances. To stop his from happening, the beaker and syringe must be washed every time they are used. 6: Average: To make the experiment as accurate as possible an average will be taken out of the 3 sets of results taken. We made up 3 test tubes of the same sugar solution, which is how we obtained 3 sets of results for an average. 7:Temperature: The temperature may affect the reliability of the experiment for example at extreme temperatures the cells of the potato may die and at less extreme temperatures the experiment may be speeded up. ...read more.


0.59 + 0.60 + 0.59 = 1.78 ? 3 = 0.593 After looking at my preliminary work it suggested that there was enough concentrations of sugar to compare each result to each other (the experiment could have been repeated with more concentrated solutions but this is not necessary). The timing of the potatoes weren't left for enough time in the experiment, as the results didn't have much change, therefore it would be much more accurate to leave them for an hour instead of half an hour to give a greater mass change. I will also be measuring the mass change as a percentage as it will be more appropriate so that reasonable results could be obtained. The graph below shows the possible outcome of the experiment. Conclusion: I feel that the experiment worked well in terms that it proved my hypothesis to be correct and we achieved what we set out to complete. I wrote my hypothesis out of my scientific knowledge for what would happen, the potato didn't taste very sweet so in this I knew the sugar content would be at a low rate. We found the isotonic value of a potato as accurately as possible by collecting an accurate set of results and finding the average. I also feel that I carried out the experiment with as much precaution / safety and fairness as possible. 0.05 0.04 0.03 0.02 0.01 0 -0.01 -0.02 -0.03 -0.04 -0.05 -0.06 -0.07 -0.08 -0.09 -0.1 -0.11 ?? ?? ?? ?? ...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

Here's what a teacher thought of this essay

3 star(s)

This is a good attempt at a report, although some sections are very brief.
1. The background knowledge section is well written but lacks researched detail.
2. The fair testing section is the strongest section in the report.
3. The results are presented well.
4. The conclusion is very brief and does not fulfill the requirement of an analysis.
*** (3 stars)

Marked by teacher Luke Smithen 08/05/2013

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

    Biology Coursework - Osmosis

    5 star(s)

    The average percentage change for a 3cm chip placed in 1.5M Sucrose solution is -31.25. Preliminary: Graphs Preliminary: Conclusion & Evaluation Conclusion The results are very much what I had expected, the potato chips in distilled water, gained mass, whilst the potato chips in a highly concentrated solution, lost mass.

  2. Marked by a teacher

    Osmosis in Potato Chips

    5 star(s)

    to a low concentration of water through a semi-permeable membrane that when both concentrations are the same, osmosis does not occur because it would be needless. One thing I noticed in my experiment was that when I took the potato chips out of the concentrations below 0.5 mol and they

  1. Marked by a teacher

    Isotonic Point of Potatoes

    5 star(s)

    d2 0.1 1 17.6 1.9 3.61 2 21.2 -1.7 2.89 3 18.3 1.2 1.44 4 20.3 -0.8 0.64 5 19.9 -0.4 0.16 0.2 1 11.8 0.3 0.09 2 12.4 -0.3 0.09 3 10.6 1.5 2.25 4 14.9 -2.8 7.84 5 10.6 1.5 2.25 0.3 1 5.2 0.58 0.34 2 4.3

  2. Marked by a teacher

    What factors affect osmosis?

    4 star(s)

    of sucrose solution, which will be altered and will be the controlled variable. The range of solutions I will be using start from 0.2M and ascending in a pattern of 0.2M incorporating 0.4M, 0.6M, 0.8M and finishing with a solution of 1.0M.

  1. Investigating the effect of changing the concentration of an acid on the rate of ...

    The points may be far away from the line because the temperature changed during the experiment, when I was not checking the temperature.

  2. See the effects of amylase on starch at different temperatures and to find at ...

    My prediction "As the temperature increases, the rate of reaction will increase, because the particles will collide more and speed up the reaction, but if the temperature goes too high then the enzyme will denature. I also predict that the enzymes will not work above 45 �C, they will work best at 37�C (body temperature)."

  1. The Effect of Solute Concentration Upon the Rate of Osmosis

    After 10 minutes of putting the first bunch of potatoes in the distilled water solution, they were taken out of their beakers with tweezers, and placed onto tissue paper to dry off the excess solution on them, so that water that was not inside the potato due to osmosis was taken off.

  2. To find out the internal concentration of a potato cell.

    concentration of the potato chip, there will be an overall net movement of water molecules passing into the chip by osmosis, so the chip will gain in mass. Where the concentration of the external solution is stronger than the internal concentration, more water molecules will pass out of the chip, so it will lose mass.

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