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Testing Osmosis From a Sugar Solution to a Potato

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Introduction

Testing Osmosis From a Sugar Solution to a Potato Introduction: Osmosis is the passage of water molecules from a weaker solution into a stronger solution through a partially permeable membrane. In this case, Osmosis applies to our practical because we are trying to see if a sugared solution has an effect on potatoes. Prediction: I predict that the higher the sugar concentration, water will transfer from the potato into the sugared solution making the potato decrease in weight, and vice versa for a lower sugar concentrations. I believe this will happen because since the solution is diluted with water, the water molecules will transfer over to the stronger solution. Thus occurring osmosis. Procedure: For this experiment, I will cork a potato, cut it to size and dry it. The potato bits will be weighed and placed in different concentrations of sugar solutions. I will wait a minimum of thirty minutes, then take the potato pieces out and weigh them again. The results will be recorded. Preliminary Work: The preliminary work was done for several reasons, but mainly to test if the experiment would actually work. ...read more.

Middle

After thirty minutes, the potato bits are dried off again and weighed once more. The weight is measured to two decimal places as well and then recorded. This experiment will be repeated three times for each concentration of sugar solution. Variables: In this particular experiment, various variables could be changed. For example: Concentration of solution Temperature of solution or Temperature of the room Amount of solution In my case, I have chosen to test the variable of concentration of solution. I decided to do this because it seemed the best variable to get good results and easier to manage. Using different amounts of concentration, a range of results can be achieved. Range: For the range of observations, I have decided to use the concentration. It ranges from distilled water to 1m. For example: Distilled Water, 0.2m, 0.4m, 0.6m, 0.8m, 1m Using the range of concentration, it makes it very easy for me to record them. All that needs to be done, is the concentrations are put in a table with the weight along side. ...read more.

Conclusion

Despite the fact that the other two tests had only lost 0.14g. Now, either I weighed or recorded the first test wrong or I could have switched the concentrations around...which I find highly unlikely. Evaluation: Although all the results were obtained, this experiment could have been more precise. The scales that were used were sometimes dirty, which could have added more weight than necessary. A better scale could be in order if the practical was repeated. Also, a scale that went to two or three decimal places would of made this practical more accurate. Another thing that could make this experiment more accurate would be some kind of device to cut the potato bits into the same lengths as each other. However, I must vouch that I tried my best to cut the potato as precisely as possible. One more thing would be a timer. In order to achieve the best results, the timing must be correct. It was slightly impossible for me to take all six-potato bits out at exactly thirty minutes. Thus, it left some potato pieces in longer than other giving them maximum exposure to greater osmosis. All in all, it was an adequately accurate practical. Fortunately, there were no anomalous results in this assessment. ...read more.

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Here's what a teacher thought of this essay

3 star(s)

In this report of an investigation into the effect of increasing sucrose solution concentration on osmosis in potato tissue, the writer too often strays into everyday language when describing osmosis instead of using scientific language. Examiners, even at GCSE level, want students to use appropriate terminology. By carrying out thorough research online before starting out on an investigation like this, students can learn this language.

The writer is to be applauded for carrying out preliminary work, something that few students bother with at GCSE. However, a discussion of control variables was missing, a vital part of any report since it persuades the reader that any changes to the dependent variable were entirely due to changes in the independent variable.

It is difficult to assess the quality of the conclusion and evaluation since no results are available. However, with the improvements listed above, this would be an adequate report.

3 stars

Marked by teacher Ross Robertson 10/05/2013

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