• 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)

    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

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

    5 star(s)

    * Although I am not controlling the temperatures at which osmosis takes place, I am going to measure the temperature of all of the solutions so that if there are any anomalies, they may be due to a change in temperature.

  1. Marked by a teacher

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

    4 star(s)

    These results support my hypothesis very well. The pieces of potato with the larger surface area did have a larger mass difference at the end of the experiment and also the mass of the potato pieces left in the sucrose solution did decrease in mass, and the pieces left in water increased in mass.

  2. Marked by a teacher

    Science Coursework: Investigating Osmosis in potato tissue

    4 star(s)

    Instead of losing weight and decreasing in size the two concentrated solutions (sugar and salt solutions) they increased in size and weight. This is quite irregular considering what my prediction said and what previous science has dictated. Why has this happened?

  1. Marked by a teacher

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

    4 star(s)

    Between 0.6 and 1M the apple pieces lost mass, this is because there was a net loss of water by osmosis. Osmosis is the movement of water from a high X to a lower one through a partially permeable membrane.

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

    Step4: We next have to make up a 15 ml solution of correct concentration and osmotic pressure. To make up a specific concentration of a solution of sucrose we use the formula: Equation1) Concentration moles/litre =Amount of solute in moles12 Volume of solution in litres Equation2)

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

    Range of results was good enough to find water potential Disadvantages of Table1: Range of results was a little to spread to find exact water potential There is no evidence of the experiment be repeated so this is only a pilot experiment Data from HSFC lab by Marylyn Marylyn's results showed a more closed spread of sucrose molarities.

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

    / Mass Before (g)). This will eliminate any minor errors 3) Time of Incubation: As the time of incubation grows, the rate of osmosis speeds up. For this experiment, all the pieces of potato will be subjected to 30 minutes of submersion. I feel that this is a good time because...

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