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

Osmosis in potatoes

Extracts from this document...

Introduction

Osmosis in potatoes Aim My main aim in this experiment is to find the isotonic level of water in a potato cell cytoplasm. We have to work out the salt concentration in the cytoplasm in terms of molarity. To find this I will test pieces of potato in different molar concentrations. From 1 molar solution to pure water. If there is no change in weight then I have found the isotonic solution, explain Apparatus � Knife - to cut the potato � 50cm3 and 25 cm3 Measuring cylinder - to measure the solutions � Water - part of the experiment Potatoes - part of the experiment � Tissue paper - to dry the potatoes after the osmosis takes place � Scales - to weigh the potatoes � Apple borer - to cut out potato cylinders Variables The variables are the things that make a test fair. The test must be fair because if it isn't then it could affect the results. * The Independent Variable is the variable that you can change. The thing that I will be changing in this experiment will be the salt solution concentration. This will help me to investigate the result of the affect that the amount of salt concentration in the solution that affects potato cell cytoplasm. * The Dependent Variable is the thing that changes because of the independent variable. This is the change in the weight of the potato, placed in different solutions of salt. The weight will be measured in grams by using scales. I will not be measuring the length because, it is very difficult to measure small pieces of potato using a ruler, which is an inaccurate device for something this small. ...read more.

Middle

Method I believe this task is in theory simple, but measuring out the solutions and getting the weights of the samples equal could be quite difficult. If the solutions are measured poorly then it could drastically affect our results. There will be an amount of control in this experiment. The potatoes do not have to be exactly the same but must be similar. One set of experiments will be carried out on the same day and all the experiments will remain in the same room I the same place. Problems may occur as water could evaporate, also the room temperature could change on different days. There will not be a strict amount of control on the potato weight because of there is a 0.1g difference between them then it will not affect the weight change dramatically. First, I will prepare the potato by peeling it. I will then push the apple borer through the potato, cutting into it lengthways. Then I will cut the cylinder into three equal lengths, which will all be altered until they, are all very similar. I have to do this twice so I have 1 cylinder for each solution. I will be doing 3 experiments so I need to do this 6 times. 1 cylinder of potato will be placed in one beaker of each molar solution. The solutions are left for 24 hours. The potatoes were placed in a 0.0 molar solution, a 0.2 molar solution, a 0.4 molar solution, a 0.6 molar solution, 0.8 molar solution and a 1.0 molar solution. Each molar solution will be set up first and will then be ready for the potatoes to be placed into them. ...read more.

Conclusion

My final results were fairly reliable, due to the precautions we took to make this a fair test, but I'm a bit disappointed that the second experiment brought out 4 anomalous results. I believe that this could have occurred, because of poor measuring and also that the weather affected our results, because the temperature may have been significantly different, and affected water evaporation, making the water more concentrated. To improve this experiment, I believe that we could have done all the experiments at the same time, so that the weather could not affect each experiment differently. We could also have used 1 litre of water, and a larger sample of potato. If the water samples were larger then it would help accuracy as an extra 2cm3 would not have affected the experiment very much. It would also have been easier to weigh the potato if the sample was larger, because the potato mass would have made it easier to measure the weight difference. We could also have used the same potatoes because different potatoes may have different isotonic salt concentrations. This could also have caused the anomalous results in experiment 2. The scales we used were also inaccurate and only measured to 1 decimal place, this made it harder to find exactly, how much weight had been lost or gained. If we had more time to do the experiment we could have done the experiment many more times and found a much better and accurate average. Also we were unable to record our experiments exactly 24 hours later due to lesson times. If we worked in a laboratory, with carefully controlled conditions and better equipment, then I think we could have done this experiment a lot more accurately, and a lot quicker. ...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. Discover what effect water with different NaCl concentrations have on potatoes, and find out ...

    This is why there is a gain in mass in the molarities lower than 0.22 (the isotonic point). I was also correct in thinking that the potato cells that were hypertonic to the solution would go turgid, because there is more water pushing against the cell walls.

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

    Planning I am investigating the effect of osmosis on a potato. Osmosis is the diffusion of water down a concentration gradient through a semi permeable membrane. I am investigating the effect of water concentration on the potato chips. This means that I will put potato chips into salt solutions of different concentrations.

  1. Use scientific knowledge and practical skills to determine the effect of a range of ...

    And as a result, I am sure that the weight of the potato will increase largely. And because the potato tissues are surrounded by a stronger solution, it will probably become smaller, and shrink. But because of such high molars of sucrose, the water can diffuse all the way, throughout

  2. Factors Affecting Osmosis.

    Hence the water will be moving from a high water potential in the 0.0M sucrose solution (distilled water) through a partially permeable membrane to low water potential in the potato cylinder. Therefore the potato cylinder will increase in mass because it is gained water by osmosis.

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