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

Osmosis in a Potato Chip.

Extracts from this document...


Osmosis in a Potato Chip Plan Hypothesis I think that the potato chips once immersed into a solution with a higher concentration of sucrose will lose weight through water leaving the cell by osmosis. I believe from my past knowledge of a similar experiment involving visking tubing and an investigation into chemical digestion and absorption that osmosis will occur across a selectively permeable membrane down a concentration gradient. Therefore once the potato chip is immersed in distilled water (a hyperosmotic solution) water will diffuse into the potato by osmosis causing a weight gain until the cells are turgid. Prediction Osmosis is the diffusion of water across a partially permeable membrane from a dilute solution to a more concentrated one (i.e. down the concentration gradient). The selectively permeable membrane only allows molecules smaller than a certain size pass through them hence the name. The cell membrane in a potato will only allow water molecules to pass freely through them as they are relatively small however it will not let a sucrose molecule pass through it due to its size. If on one side of the membrane there is a higher concentration of sucrose molecules (i.e. a smaller concentration of water) water molecules will diffuse through the selectively permeable membrane to reduce the concentration of sucrose molecules. This is so that the concentration of water on either side of the membrane is equal and an equilibrium has been reached. From my past knowledge involving red blood cells being immersed in a hyperosmotic solution (distilled water), water diffused by osmosis into the red blood cells from an area of high concentration of water down the concentration gradient. This resulted in the red blood cells absorbing too much water due to them only having a slightly elastic cell membrane. However, in a potato chip, if immersed in distilled water, will increase in weight by absorbing distilled water by osmosis due to their being a lower concentration of water inside the cell vacuole. ...read more.


This can be easily controlled by cutting them off with a scalpel. Safety I will need to ensure that my experiment is safe, I can do this by taking care when I use the scalpel when cutting the potato, care will also be taken how I hold the potato when using the cork cutter in case it goes straight through the potato. I will also take care with the glassware that I use e.g. test tubes so that breakages will not occur. This can also be avoided by being as organised as possible and only having the necessary equipment on my desk at one time. Lab coats will be worn to avoid spillage of fluids and especially the sucrose solution, as this is very sticky on to my clothes. I shall also be careful and aware of other people's actions and experiments. Analysis From my table of results and the graph that I have drawn from my results I can conclude that my prediction was correct. The potato chip did in fact gain weight when immersed in a distilled solution and it also lost weight when immersed in a solution of sucrose as stated in my prediction. These results can be easily explained by having an understanding of osmosis. The potato chip gained weight when immersed in distilled water because water molecules diffused into the chip by osmosis across the cell membrane thus causing a weight gain. The water diffused across the cell membrane because there was a higher concentration of sucrose and salt molecules (i.e. lower concentration of water) inside the cell than the water outside the cell creating a concentration gradient. This caused the water molecules to move into the cell to equal out the concentration of water and to reach equilibrium. This intake of water would have caused the cell vacuoles to expand in size exerting pressure on the cell membrane and consequently making it stretch until it reached the cell wall and became fully turgid. ...read more.


There was also an error in the weighing of the potato after the experiment because of excess sucrose solution on the potato after being withdrawn from the solution. I tried to eliminate this by leaving the chip on some paper towel however this may have taken too much water off the potato thus affecting the mass. I was also lucky enough not to get any anomalous results I think I can put that down to the accuracy of the procedure and also the use of using repeats. This would prove the results were more reliable and anomalous results would become more apparent. There was also a time delay in some potatoes coming out of the solutions, therefore some would come spend a longer time in the solution than they were meant to. This would have resulted in a larger weight change. This could have been avoided by starting the experiment for different concentrations at different times. However this would not have been practical due to time limitations. If I were to perform this experiment again I would make a few changes and improvements to improve my results and also to increase my investigation. To increase and widen my investigation I would use a different variable or increase to the measurements I took. For example I would have liked to measure the length of the chip after the experiment to see if an increase in size or plasmolysis had occurred. I would also use a different variable for example changing the water temperature this would increase the rate of osmosis and therefore the speed of the water molecules. I would also try to increase the accuracy and reliability of my results by investigating more than one potato, taking more repeats. I would also start my experiments at different times to stop there being a rush at the end. I would also use larger potatoes so that a larger variation in the change in weight could be obtained. Royce Peever Biology Coursework ...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)

    In this osmosis investigation, I will try to keep constant the factors that affect the rate of osmosis apart from the concentration of sucrose solution (and water) for this is what I am investigating through this report. I shall use potato chips from the same potato because it is presumed

  2. Marked by a teacher

    How does the concentration of a sucrose solution affect the rate of Osmosis in ...

    5 star(s)

    I will make my results valid, precise and reliable in the following ways: * I will measure the lengths of the potato cylinders very carefully so that the surface area is not changed, as a change in the surface area may change the rate of osmosis taking place.

  1. Marked by a teacher

    Investigating the effect of sucrose concentration on osmosis in potato cells

    4 star(s)

    This happened because water moved across the partially permeable cell membrane by osmosis. It moved both ways, but because the concentration of water in the solution was higher than that inside the potato cells, more water molecules moved into the potato than moved out, so the potato cells gained mass.

  2. Marked by a teacher

    To investigate how varying the concentration of sucrose solutions affects the rate of osmosis ...

    3 star(s)

    One large potato 2. Six Petri dishes 3. Twelve labels 4. Six beakers 5. Six droppers 6. One scalpel 7. Distilled water 8. Sucrose solutions of concentrations 0.125M,0.25M, 0.50M, 0.75 M and 1.00M 9. One cork borer of size 2 10. Ruler 11. Graph paper 12. Weighing scales Method: I will use the cork borer to obtain 30 potato cylinders.

  1. Osmosis, What is the effect of sucrose concentration on the rate of osmosis in ...

    The solutions utilized were created from the following table Sucrose (ml) Water (ml) Sucrose Concentration Created (Moles/Litre) 20 0 1.0 0 20 0.0 Pilot Test Results Table Sucrose Concentration (Moles/Litre) Mass Before (g) Mass After (g) Mass Change (g) % Mass Change (2 decimal places)

  2. Osmotic pressure

    In plant cells, there are two cell barriers, wholly permeable cell wall and partially permeable cell surface membrane. In A the entry of water into the vacuole by osmosis causes an increase in cell volume and turger pressure which is opposed by the cell wall pressure.

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

    Another important factor of a fair test is to start and stop the clock as quickly as possible. This meaning that we should start the clock as soon as the potato is put inside the test tube, and stop the clock as soon as 20 minutes have passed.

  2. Osmosis Practical

    The cells on the outside of the cube lose their water first, until there is none left. The cell next to it then starts to diffuse its water to the outside cell, the water then diffuses out of the potato, and so on.

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