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

Osmosis. I was aiming to find out the effect a concentration of solute (in my investigation, sugar) has on the mass of potato tissue.

Extracts from this document...

Introduction

OSMOSIS COURSEWORK I have completed an investigation into the osmosis in potato cells. During the investigation I was aiming to find out the effect a concentration of solute (in my investigation, sugar) has on the mass of potato tissue. I then recorded my results into a table and two graphs, which are attached. In my investigation, I controlled the following variables: * Type of potato * Size of potato * Temperature of water * Type of solute (sugar) The independent variable in my investigation was: * Concentration of solute Analysis Based on the table and the two graphs attached, my results show me that only the potato placed in pure water, increased in mass. All the other potatoes, which were placed into a solution of sugar and water, decreased in mass. The pattern is that the higher the concentration of sugar, the higher the decrease in mass. This change of mass occurs due to a process called osmosis. Osmosis is the diffusion of water through a semi permeable membrane, separating solutions of different concentrations. The water passes from a region of high concentration to a region of low concentration, until the two concentrations are equal in concentrations of water. ...read more.

Middle

This is a good range which allows me to be more confident in my conclusion. I can improve this by having more readings within this range (e.g. twenty readings instead of ten), or by increasing the range (e.g. 100cm� water to 100cm� sugar solution). My ranges do not provide confidence to my conclusion: Although the ranges for the nine readings above (the table excludes the potato placed in pure water) are not huge, it lacks confidence. For the readings 20cm�, 30cm�, 35cm�, 40cm�, 45cm� and 50cm�, the ranges are small, making me confident in my results. In contrast, the readings for 10cm�, 15cm� and 25cm� are too big, questioning the confidence in my results. Whilst carrying out the experiment, I did not find any difficulties. However reliability of the equipment to carry out the experiment at times certainly did cause a problem. One example of equipment which caused complications was the measuring cylinder used measure a certain amount of sugar solution/water. The measuring cylinder was only able to measure to the nearest cm� which is not accurate enough for its purpose. Nevertheless, the mass balance used, measures to 2 decimal places which is very accurate for its purpose. ...read more.

Conclusion

This can easily be avoided so apart from that there were no minor or major hazards that I had to tackle. Similar Experiment Below is an experiment similar to the one I completed. In contrast to my experiment, the solute that was used was salt instead of sugar. In this investigation, the following variables were controlled: * Type of potato * Size of potato * Temperature of water * Type of solute (salt) The independent variable in this investigation was: * Concentration of solute The results of the experiment are seen in the table below: Like the experiment I completed, when the potato was placed in a hypotonic solution (0%, 25% salt solution), water enters the cell sap by osmosis due to it having a low concentration of water compared to the water in its surroundings. This causes the potato to gain in mass, which can be seen in the table above. When the potato was placed in a hypertonic solution (50%, 75%, 100% salt solution), water leaves the cell sap by osmosis due to it having a high concentration of water compared to the sugar solution. This causes the potato to lose mass. The results from this experiment clearly back up the data I received from completing my experiment. ?? ?? ?? ?? ...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. Determine the solute concentration of potato tissue

    water, and then eight different concentrations of sucrose solution, evenly spread out. By looking at my graph and results from the preliminary experiment I can see that as the concentration of sucrose solution increases, the percentage change in mass decreases.

  2. Osmosis investigation

    Carry them to the scales, unwrap one at a time. Weigh one and record the answer in your results table under the column mass before. To be able to identify the chip, you must create a drawing pin scheme: firstly, get coloured pins and find 3 colours which there are 6 of.

  1. The endeavour of this investigation is to ascertain if there is any effect of ...

    The sucrose solutions used were 0.0, 0.25, 0.5, 0.75 and 1.0 mol dm-3, the potato pieces which had been cut into 1.5cm cubes; 4cm lengths of cylinders made with a cork borer and cuboids of dimensions 1.5 by 1 by 0.3cm, these three different shape chips had different masses to begin with: 3.6, 1.25 and 1.07g respectively.

  2. An investigation into osmosis in potato tissue.

    However, placing the chips in liquid will cause them to gain extra mass as they will not be dry when re-weighed - where changes are marginal or non-existent, an increase in mass could be perceived to have occurred due to the extra mass of the liquid.

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

    The water molecules in the solution and in the potatoes might also evaporate, a process I wouldn't be able to completely control. * Type of cell is vital in osmosis, because of the fact that the permeability of the membrane and the surface area of the membrane can be different

  2. Find out the effect of changing solute concentration on osmosis in potato tissue.

    And so the water from the potato will loose water to try and balance the scale. By losing the water it wall cause the mass to drop. When the cells have lost a lot of water and when they are weak we call the cells flaccid But even if u

  1. An investigation to find out the effect of salt solution concentration on potato tissue.

    in the water itself, to a low concentration, i.e. in the potato chip. So, the chips in higher salt concentrations will have a larger mass than in lower salt concentrations. Preliminary Practical: 0% 0m pure water 100% 1 molar Apparatus: Test tubes and rack 2 potato chips Cork borer Measuring cylinder Scale/ruler Knife White tile Stopwatch Distilled Water Prediction

  2. Osmosis investigation.

    After a certain temperature the cell will deteriorate and another temperature will be the optimum temperature for osmosis. ? Time The longer one leaves the potato cylinders in the solutions the more time the cells have to absorb water into the cell or reject it depending on the concentration of the solution.

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