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

Osmosis Coursework

Extracts from this document...

Introduction

GCSE Osmosis Coursework Strand S Aim: We are trying to find out how sucrose concentration affects the mass and length of potato chips. Osmosis is very important to plants because they absorb water through their roots by osmosis. Plant cells become turgid when they absorb water, this is important because it makes the leaves erect to absorb more light from the sun for photosynthesis. When plant cells have lost water it becomes flaccid or plasmolysed. Water stops entering plant cells when the cell becomes turgid, because the cell wall rejects water. Osmosis in animal cells is very different as animal cells don't have a cell wall. Therefore the cells burst if there is too much water. If the cell doesn't have enough water it shrivels up. Prediction: I predict that the potatoes in a weak concentrated sucrose solution will increase in mass and length. I also predict that potatoes in a highly concentrated sucrose solution will decrease in mass and also length. The rate that it passes depends on pressure, concentration and temperature of the molecules or solutes on either side. If the solution is a sucrose solution then the mass of the potatoes will decrease. This is because more water will be moving out of the potato than entering it. A semi-permeable membrane allows small molecules through, this means that water molecules are able to move freely, however the sucrose molecules are too big and will not be able to go through. ...read more.

Middle

I will change the concentration of sucrose solution from 0.0 (water) to 0.8. This is to see the affect on potatoes when put in different concentrations. Safety: Method ? A range of sucrose solutions will be prepared with concentrations from 0.2 M to0.8M, in intervals of 0.2M, as well as one test tube filled with distilled water. ? Sections of potato will be cut using a cork borer as this is the most accurate way of getting the lengths equal. ? About 15 ml of each concentration of sucrose will be placed in three test tubes and labelled. ? To each test tube a cut piece of potato will be added and its mass added to the label. These will be left for about 1 hour ? Then the potato pieces will be removed, the surface solution removed using paper towels and weighed. ? Three readings are taken for each concentration in order to get an average and reduce the effect of inconsistent results. ? As it is difficult to get the cut potato pieces to the same mass it was decided that a percentage change in mass will be used to compare the data in the results, as this would be far more accurate. Results Concentration of sucrose solution and water Initial mass of potato chips(g) ...read more.

Conclusion

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. Another way of improving the results would have been to leave the experiment running longer, this would have enabled me to find the point when the potato can no longer take in any more water and when the potato cannot lose any more water and therefore get a more accurate result. There also another problem that could have gained a less accurate result this was the fact that the cork borers kept on overlapping and causing some chips to not be the same size as the others Further work To find out whether or not this investigation could have investigated the effect other factors had on the rate of osmosis. The temperature of the water in the sucrose solution is one. It would prove that the protein in the potato membrane stops after the optimum temperature which is about 37 degrees and osmosis would no longer take place as the membrane is ruined. We could also investigate how sucrose concentration affects the mass of other vegetables or foods as this could give us an entire view on the affect of osmosis in potatoes. Furthermore we could try and change the sucrose solution from sucrose to fructose and see if the different types of sucrose have diverse changes to the potatoes. ?? ?? ?? ?? Jamil Nwoko 11CMC ...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

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

    5 star(s)

    As water passes out, the sap vacuole begins to shrink. The cells are now limp and it is said that they are flaccid. As more water leaves the cells the cytoplasm shreds away from the cell wall causing the cell to become plasmolysed.

  2. Marked by a teacher

    Photosynthesis Coursework

    4 star(s)

    As I have already stated, my preliminary experiment was not accurate enough to justify being used as my main experiment, mostly due to the fact that I was relying on all the bubbles being the same size, which they clearly weren't, however many of the smaller inaccuracies also apply to my main experiment.

  1. Marked by a teacher

    Biology Coursework - Osmosis

    3 star(s)

    For my pilot test, I used 33mm of potato. I carefully cut it to 33mm and weighed to around 1g, however I wasn't too picky with accuracy, as it was only a pilot. I used 15mls of calcium carbonate solution- this was the amount needed to cover one piece of potato.

  2. Osmosis Coursework

    These cells are said to be plasmolysed. When plant cells are placed in a solution which has exactly the same osmotic strength as the cells they are in a state between turgidity and flaccidity. We call this incipient plasmolysis. "Incipient" means "about to be". Variables: To create a fair test certain aspects of the experiment will have

  1. Osmosis is defined as 'the movement of water molecules from an area of high ...

    osmosis action would reach its maximum capability, and therefore tell us how much water could be transferred for each solution. Repeating the same tasks many other times wouldn�t have been very useful, since we had already done the result 3 times, and ALL the results were reliable.

  2. Free essay

    Osmosis Coursework

    * A scalpel is used to cut the potato chips so that they are all equal lengths. * A measuring cylinder is used to measure the solution and distilled water. * Tweezers are used to pick out the potato chips from the beakers.

  1. Osmosis Coursework

    It is important that the same potato is use to cut out each chip to make the experiment a fair test. * 1 Scalpel: to cut the potato into chips of the same size - 2.5cm long * 2 Cork borers: 1 to cut the potato chips with the same diameter.

  2. osmosis coursework

    1.1 1.1 -0.1 -0.1 -0.1 30% 1.2 1.2 1.2 0.9 0.9 0.9 -0.3 -0.3 -0.3 40% 1.2 1.2 1.2 0.8 0.7 0.75 -0.4 -0.5 -0.45 50% 1.2 1.2 1.2 0.7 0.7 0.7 -0.5 -0.5 -0.5 My results show that the mass of the potato increased and also decreased.

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