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

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

Extracts from this document...


Year 10 coursework - Osmosis How does the concentration of salt solution affect osmosis in potatoes? Introduction Osmosis is movement of water through a selectively permeable membrane, from where there is a higher water concentration (or water potential) to where the water concentration is lower. In this piece of coursework I will answer the question, 'How does the concentration of salt solution affect osmosis in potatoes?'. If you put a piece of potato into pure water, the water concentration is obviously higher outside the potato. Therefore water moves into the potato by osmosis. This will cause the potato piece to swell. However, if you put a piece of potato into a strong salt solution (where the water concentration is low), then water will move out of the potato. The potato piece will therefore shrink. If a salt solution has exactly the same water concentration as the potato piece, then it is likely that there will be no overall movement of water in or out of the potato. ...read more.


If you put a plant cell in water, water enters by Osmosis, then swells up. However, the cell will not burst. This is due to the fact that the cell walls are made from cellulose, which is extremely strong. Eventually, the cell stops swelling, and when this point is reached, we say the cell is turgid. This is important, because it makes plant stems strong and upright. The experiment I will do is to find the water potential of a potato, by putting potato pieces into different solutions of salt of known concentrations, until I find the concentration where the potato piece stays the same size. To make this experiment a fair test, I would need to keep everything else constant as far as possible. For example, I need potato pieces of the same size, and should always use the same volumes of salt solutions. Prediction I predict, that as concentration increases, the weight and length of the potato chip will decrease. ...read more.


Relating this to the potato chips: basically, as the concentration of salt in each solution increases, the water in that solution is less able to move to the potato, causing water from the potato to move to the solution, decreasing its length, weight and width. Osmosis is established when a semi-permeable membrane is placed beween two solutions. In biological systems osmosis is the exchange of water between the toplasm and the surrounding medium, with the plasm membrane being the semi- permeable membrane. An example of this in my results is the test at 1 molar. In other words, it becomes dehydrated and loses water through plasmolysis. If the concentration of the salt solution (in our case Glucose solution) outside the cell is less than that inside the cell, this means that the solution is Hypotonic to the cells of the potato chip. The water will diffuse into the cells, making it turgid. This would explain why potato chips put into a solution of 0 molar seemed very firm compared to the potato chip used for 1 molar, this was because the cells of the potato had lost their turgor, and had become flaccid. ...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

4 star(s)

A very clear account showing a detailed understanding of osmosis written using a good standard of GCSE level biological terminology. Better coverage of variables needed for 5 stars.

Marked by teacher Adam Roberts 10/05/2013

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 variable I have selected as my independent variable is the concentration of sucrose solution that the potato chips will be placed in. The dependant variables I have chosen to measure are: the mass of potato chip after osmosis and the volume of solution remaining after osmosis.

  2. Marked by a teacher

    Isotonic Point of Potatoes

    5 star(s)

    Constant Surrounding conditions like temperature and pressure The trials will all be conducted in the same surrounding conditions Temperature and pressure both influence the rate of diffusion hence they have to be kept constant to ensure a fair comparison. Volume of each solution used This will be measured using a

  1. Marked by a teacher

    An Experiment to determine Water Potential in Potato Tissue.

    4 star(s)

    I think this is caused by experimental errors. The technique of weight measuring might have caused many problems. I might not have settled the weight measurer completely before I used it. Also some water or solution might have been left on weight measurer from person before which could have affected the mass.

  2. Marked by a teacher

    Science Coursework: Investigating Osmosis in potato tissue

    4 star(s)

    Why has this happened? Maybe the 2 spatulas worth of salt and sugar weren't enough and we needed a more concentrated solution - maybe 3 or4 spatulas worth was needed. Maybe we needed to leave it in there for longer as 10 minutes might not have been enough (although in our last pre test it proved my prediction and only 5 minutes was needed).

  1. Marked by a teacher

    Osmosis Investigation - How Does Salt Solution Concentration Affect The Mass Of Potatoes?

    4 star(s)

    However, if the potato mass stays the same after the experiment, this means that the water/salt solution and the potato must be of equal concentration. Equipment Potato, Borer, Beakers, Measuring Cylinder, Stopclocks, Distilled Water, Electronic Balance, Salt solutions of various concentrations.

  2. Aim To determine the water potential of a potato tuber cell

    I also found by looking at the line graph drew that the mass of most potato cylinders decreased, even with a concentration of 0.36M. A pattern can easily be seen in the line graph, the pattern is as the concentration of sucrose molecules increases, the percentage change in mass decreases.

  1. The effect of acid on the cell membrane

    Molarity HCl Colorimeter Reading (Absorption) Percentage Absorption (%) 0.2 0.36 18.00 0.4 0.80 40.00 0.6 0.89 44.50 0.8 0.86 43.00 1.0 0.90 45.00 These results show me that up to 1M HCl the pigment in the red cabbage is released. Although I could increase the concentration of acid, I think the results would not be useful as at 1.0M it is already at 90% absorption.

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

    12 13 14 pH range Universal indicator red red orange-red orange pale orange orange-yellow pale yellow green-yellow green dark-green blue blue blue blue blue A colorimeter could be used instead, to announce or record when the agar has turned completely colourless.

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