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

Investigating the Effect of Concentration on the Rate of Osmosis in Potato Tissue.

Extracts from this document...

Introduction

Investigating the Effect of Concentration on the Rate of Osmosis in Potato Tissue Introduction: Osmosis is the net movement of water molecules from an area of high concentration to an area of low concentration across a selectively permeable membrane. It is only net movement as the molecules will move randomly, and therefore though most will move into the area of low concentration, some molecules will still move against the trend. Factors that affect the rate of osmosis are listed below with an explanation: * Concentration Gradient: If the concentration gradient of water molecules is high, then the rate of osmosis will also be high as there is a greater 'pressure' that will cause the net movement of molecules into the area of low concentration. There is also a greater 'need' for the concentration on both sides of the membrane to be equalled, and so the rate will be high. This can be illustrated with the aid of diagrams. Very high concentration Rate=High Very low concentration High concentration Rate=Lower Low concentration * Temperature: If the temperature is higher, then the molecules all have more energy and therefore move faster. If the molecules move faster, then the time it takes for them to move through the selectively permeable membrane is shortened. This therefore means that the rate of osmosis is higher. On the other hand, if the temperature is lower, then the molecules move slower and the rate of osmosis is lower too. * Pressure: If the pressure is higher, then that means there is less space for the molecules to move in. ...read more.

Middle

It also allows us to compare that potato chunk with other potato chunks fairly. Finally, the percentage change was then converted into a rate (Percentage Change / time) so that we could see the rate of osmosis for each potato chunk and still be able to compare it with the other results. Apparatus: Potato Potato Corer Scalpel 5 Petri Dishes 0M 0.2M 0.4M 0.6M 0.8M 1M Electronic Scales Paper Towels Prediction: I believe that any potato chunks left in a sucrose solution of lower than 0.27M (see secondary source) will gain mass as they will have a lower concentration of water molecules in them than in the solution surrounding them. Therefore, the net movement of water molecules will be into the chunks via osmosis, in an attempt to even up the concentration of the inside and outside of the potato, since sucrose molecules cannot pass through the selectively permeable membrane. On the other hand, I believe that any solutions the potato chunks are immersed in above 0.27M will cause their mass to decrease. This is because the concentration of water molecules is greater inside the potato, thus causing the net movement of water molecules out of the potato and into the solution, causing a decrease in the mass of the pieces. Also, I think that the further the sucrose solution that the potato is immersed in is from 0.27M, the greater the rate of osmosis, whether it be into or out of the chunks. ...read more.

Conclusion

While this may not solve the problem of the amount of water being dried off, it will ensure that all the readings after the initial ones are all relative to each other. We could also make sure that all the potatoes are of sufficient size, thus preventing the issue of tissue nature being a factor. This may, in turn, allow all the chunks to be taken from the same area (e.g. the middle) of the potato, again ensuring the cells are of the same nature. On the issue of size and shape, if such equipment were available to us, we could use much more accurate (or even machines) equipment to measure and cut the pieces. We could also make improvements to the experiment by ensuring that an equal amount of solution is placed into the petri dishes, allowing the entire potato piece to be submersed in it. In order to EXTEND the experiment further, a much larger range of solutions could be used in the investigation in order to explore whether or not there is an actual maximum rate, and what it is. In addition to this, to try and find a more exact value for the molarity of sucrose inside potato cells, we could conduct the investigation, concentrating mainly on the molarities of value 0.2-0.3M. Finally, the experiment could be conducted over a much longer period of time, allowing us to find more results, making it easier to see the trends and to isolate anomalies. Geoffrey Tan The Effect of Concentration on the Rate of Osmosis ...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)

    The water molecules will diffuse through the partially permeable membrane and into the area of high concentration, i.e. the strong sucrose solution. The cells lose water and become flaccid (flabby). Water has diffused out by osmosis and therefore the potato chips where the sucrose concentration has been high, have decreased in mass.

  2. Marked by a teacher

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

    5 star(s)

    The highest concentration I can do before the solution becomes saturated is 20% sucrose. I decided that the way in which I would get the most accurate and well spread out results would be to do ranges of equal intervals in between so I chose to do 0% sucrose, 5%, 10%, 15%, and 20%.

  1. Marked by a teacher

    Investigate the effect of surface area on osmosis in potato tissue.

    4 star(s)

    I collected six sets of data, which was an adequate amount to show a pattern on the graph I produced. Although I would have expected the pieces of potato with a surface area of 48cm2 to have a mass difference double to that of 24cm2 because it is double the surface area, but my results did not show that.

  2. Marked by a teacher

    Science Coursework: Investigating Osmosis in potato tissue

    4 star(s)

    * 1 x blunt knife - to cut the potato into equal sizes (so surface area isn't affected).

  1. Marked by a teacher

    Experiment to find the effect of sucrose solution concentration on potato and apple tissue.

    4 star(s)

    This is because more water is needed to reach the equilibrium, the increased pressure in the cell causes it to become more rigid. In the solutions with the higher concentrations the cell needs to lose water for the X to be in equilibrium, because the cell loses water the pressure drops making the cells flaccid.

  2. To investigate the factors that effect osmosis in living tissue.

    not in a test tube, this is as the test-tube may break whilst we are using the glass-rod to stir the solution and to make sure that all the solute particles dissolve. Stage5: The vegetable cylinder will then be added to the required concentration inside a test-tube where a rubber bung will be placed to prevent the solution evaporating.

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

    In addition, the concentrations below the two extremes will begin to catch up with the boundaries creating an awkward graph. At 5 minutes, hardly any osmosis will have taken place. Even a small anomaly in one measurement could result in an experimental failure because the values will be so small.

  2. Osmotic pressure

    o I then recorded both the mass and length of the potato chips, giving me two sets of results. After I had done this I was then able to plot these results onto a graph. Actual Experiment Results: Concentration of sucrose solution (M)

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