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An Investigation into the Water Potential Of Root Vegetables.

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Introduction

An Investigation into the Water Potential Of Root Vegetables. The aim of this investigation is to find the water potential of two root vegetables and to evaluate any differences that are found. Root vegetables take in the water they need through a process known as osmosis. Water moves from an area of high water potential to an area of low water potential through a partially permeable membrane. The water potential of root vegetables depends on the concentration of solutes within their cells. Starch is not soluble so the starch content of the vegetables will not affect the water potential. Sucrose however is soluble. In the investigation I will find the isotonic solution for each vegetable based on the principle that when the vegetable is in a hypertonic solution it will lose water (and become plasmolysed) and therefore lose mass and that when the vegetable is in a hypotonic solution it will gain water (and become turgid) and gain mass. By calculating the percentage change in each vegetable piece I will be able to find the concentration of sucrose solution at which the vegetable will gain no mass. ...read more.

Middle

Having a range of five solutions I will be able to make sensible conclusions as to what is happening because I will be able to look at a suitable range of data. Safety. Care will be taken when using the knife and when using glass wear. The ceramic tile will be used as a cutting board so that the knife does not scratch the work surfaces. Prediction. I predict that the swede will have the highest concentration of sucrose and therefore the lower water potential of the two vegetables. The reason for this is that swede is a sweet root vegetable where as potato is not. Sucrose is a sugar present in root vegetables and has a sweet taste, so I think that the swede will contain the most sucrose. This will mean that more of the five sucrose solutions will be hypotonic towards the swede and that the isotonic solution will be of greater sucrose concentration than the isotonic solution of the potato. Results. A table showing the results for the potato pieces. Potato Number1 Concentration of solution (mol) Mass before (g) Mass after (g) ...read more.

Conclusion

This meant that I could calculate averages from results that were only very slightly inaccurate and still be able to make good conclusions from them. The procedure could be improved in several ways. Each vegetable piece should have its own boiling tube so that each piece has the same exposed surface area. This would make the test a little fairer. The solutions should be measured out in large quantities and the boiling tubes should then be filled from the large amounts of solution made up. This would eliminate any slight error occurring from one concentration of solution for one vegetable being slightly different from the concentration of the same solution for the other vegetable. A final change to the procedure that I would make to solve the problems arising when cutting the vegetable pieces would be to use some sort of jig. This would mean that each piece is identical in size and is best described using a diagram: 1 The potato numbers refer to the order of the pieces in the boiling tube; 1=bottom piece, 2=middle piece and 3=top piece. 2 The swede numbers refer to the order of the pieces in the boiling tube; 1=bottom piece, 2=middle piece and 3=top piece. ...read more.

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Here's what a teacher thought of this essay

4 star(s)

This is a well written report that covers all of the necessary aspects of the investigation.
1. The starting section of the report needs to be broken up with subheadings.
2. The tables of results are well presented.
3. Researched information needs to be referenced and a section for this included.
4. The conclusion is concise and so more analysis could be conducted.
5. The evaluation shows a good understanding of some scientific processes and contains good suggestions.
****

Marked by teacher Luke Smithen 23/07/2013

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