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

To determine how the concentration of salt water affects osmosis in potatoes

Extracts from this document...


Investigation - To determine how the concentration of salt water affects osmosis in potatoes Planning Aim - To determine the effect the concentration of water has on osmosis in potatoes Prediction - I think that when the concentration of salt water is higher then there will be a greater loss of weight in the potatoes. This is because the water molecules inside the potato move from an area of high water concentration to low water concentration. When the concentration of salt is higher it will therefore have a lower water concentration meaning that there will be a steeper concentration gradient. The salt molecules will not diffuse into the potato because they cannot pass through the partially permeable membrane. I think that in all the salt solutions above 1% the potato will become plasmolysed. Whilst this doesn't usually happen the potato will be surrounded by solutions of a very high concentration. It will become plasmolysed because a lot of water will have left the cell to the point when the cell wall can no longer shrink and the cell membrane will tear away from the cell wall. This will kill the potato cell. ...read more.


Original mass (g) New mass (g) % Change 0% 2.95 3.01 2.03 1% 2.97 2.94 -1.01* 2% 2.85 2.63 -7.72 3% 3.09 2.83 -8.41 4% 2.83 2.67 -9.19 5% 3.12 2.86 -8.33 Concentration (%) Original mass (g) New mass (g) % Change 0% 2.82 2.88 2.12 1% 2.98 2.87 -3.69 2% 2.96 2.77 -6.41 3% 3.08 2.87 -6.82 4% 3.02 2.82 -6.82 5% 3.05 2.7 -11.48 Concentration (%) Original mass (g) New mass (g) % Change 0% 3.34 3.41 2.1 1% 3.03 2.99 -4.62 2% 3.22 3.13 -2.8* 3% 3.35 3.22 -3.88* 4% 3.2 3.09 -3.44* 5% 3.33 3.2 -3.9* Concentration (%) Average % Change 0% 2.08 1% -4.16 2% -7.07 3% -7.62 4% -8.01 5% -9.91 * Believed to be an anomalous result and therefore excluded from calculations Analysis Whilst no formula can be determined to summarize the trend, there is a clear trend. The trend is shown clearly by the graph overleaf. When the salt water is more concentrated, above 2% more weight is lost from the potato because the cells become plasmolysed and die. However in tap water there is a small gain in weight, because the cell becomes turgid. ...read more.


I therefore think that the evidence is sufficient. I think that the experiment could have mainly been improved by being more precise generally. Due to time constraints we seemed to choose reliability over accuracy and produced several anomalies in the process. If I could repeat the experiment I would do only 2 sets of results but be as precise as possible. If I then didn't have 2 sets of results close together I would do repeats where necessary. I think that the way we did it meant that our conclusion is not as firm as it could have been. Also we could have dried the potato off more thoroughly because the excess of surface moisture on the potato made it too heavy and adversely affected the results, especially in the 3rd set. I think that using sugar water instead of salt water could extend the enquiry. This could finally prove the conclusion by showing that it works for solutions apart from salt. Or use a different plant apart from potatoes such as apples because at the moment the conclusion only describes potatoes in salt water and is therefore not particularly "concrete". Jonathan Laurence 10.5 ...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 Green Plants as Organisms 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 Green Plants as Organisms essays

  1. Determine the water potential of potato tuber cell with the varying affect of solute ...

    This also turned out to be correct because I knew that since there is a higher concentration of solute molecules in the solution it means that now there is a lower concentration of water outside the cell which will mean that less water will go in the cell.

  2. The effect that different concentrations of salt solution in the water has on strips ...

    Another reason why test tubes would be better is because a cork can be stuck in the top of the test tube, reducing evaporation, while the plastic dishes were not covered at all, which increased the risk of more inaccurate results.

  1. Investigate and find the water potential of baking potatoes and sweet potatoes in (N/mm2) ...

    The water bath will succeed in keeping the temperature stable and accurate and will allow the protein channels to let water in quicker than at room temperature, this would show a more noticeable change on the weighing scales than simply a small 0.1% increase/decrease.

  2. Osmosis, I predict the mass of potato will first increase then start decreasing as ...

    Then I will measure the mass using a scale. Safety: To make this experiment safe I will need to: 1. Be careful when using the borer as it is sharp 2. Do not taste or eat the potato to avoid the ingestion of dangerous chemicals 3. Be careful using a knife Fair Test: To make it a fair test I must: 1.

  1. Monitoring living organismsthe more concentration of salt there is, the less growth of the ...

    This is then allowing the plant to stay at usually the same temperature. After 12 hours would go past everyday, I monitored to see if there would be any progress of the growth of the seeds. Then, I would put 2 teaspoons of water into each egg-hole, so then the growth of each egg-hole would still continue.

  2. Investigate the use of Osmosis in potatoes

    This water increases the mass of the potato. If the plant cell is placed in an isotonic solution, a solution that has an equal concentration of water to the plant cell, the two water potentials have the same value so there is no movement of water.

  1. Potato and Osmosis Investigation.

    region of lower concentration; the way osmosis diffuses is through a semi-permeable membrane which allows only small molecules (e.g. water molecules) to pass through its partially permeable membrane. The molecules will continue to diffuse until they have reached the state of equilibrium, the balance between molecules on either side of the cell wall, the semi-permeable membrane.

  2. Water moves from a high concentration gradient of water to a low concentration of ...

    The potato will turn to turgid looking very plumpy. 0.2 Still the outside concentration gradient of water is still higher than the concentration gradient of water in the potato. But this time the water will move into the potato more slowly as it blocks some sucrose molecules from getting in.

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