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Does the strength of a salt solution affect osmosis in a potato?

Extracts from this document...

Introduction

Does the strength of a salt solution affect osmosis in a potato? Factors Factors that could affect the experiment: - * Temperature of water * Type of potato * Amount of solution * Amount of time the potato is in the solution Factors that I will change in my investigation: - * Percentage of salt in solution Preliminary Equipment 7 Beakers (250ml) 7 strengths of sugar solution (100ml of each strength) as follows 1x 0.0% salt 1x 0.5% salt 1x 1.0% salt 1x 1.5% salt 1x 2.0% salt 1x 2.5% salt 1x 3.0% salt Potato Ruler Cork Borer Knife Preliminary Plan 1. Cut into potato with cork borer. 2. Measure and cut 1.5cm of potato from the cork borer. Repeat steps 1. and 2. until you have 21 pieces of potato (3 per beaker) of equal size 3. Pour approximately 100ml of 0% salt solution into the first beaker. Label this beaker "0%" or "Water". 4. Pour approximately 100ml of 0.5% solution into second beaker. ...read more.

Middle

Potato piece 3 length after 1hour (mm) Average potato piece length after 1hour (mm) Increase or decrease in length of potato piece after 1 hour (%) 0% 17mm 18mm 18mm 17.7mm +17.3% 0.5% 18mm 16mm 18mm 17.3mm +15.3% 1.0% 15mm 16mm 15mm 15.3mm +2% 1.5% 15mm 15mm 14mm 14.7mm -2.7% 2.0% 16mm 15mm 15mm 15.3mm +2% 2.5% 15mm 17mm 14mm 15.3mm +2% 3.0% 14mm 16mm 14mm 14.7mm -2.7% Preliminary Conclusion My preliminary results had no pattern to them, which suggests that the % strengths of sugar solution were incorrect. I then tried percentages from 0% to 10% salt solution, going up in steps of 2% (i.e. 0%, 2%, 4%, 6%, 8%, 10%). This also proved unsuccessful, so I will try 0%, 5%, 10%, 15%, 20% and 25%. Revised prediction See "PRELIMINARY PREDICTION" Revised Method See "PRELIMINARY METHOD", but change the amounts stated in "PRELIMINARY CONCUSION" Revised Equipment * 6 beakers (250ml each) * 6 x 100ml strengths of salt solution (0%, 5%, 10%, 15%, 20%, 25%) * Potatoes * Ruler * Knife * 6 gauge cork borer * Knife Revised Results Strength of solution (%) ...read more.

Conclusion

(This also can tell us that the solution inside the cells of a potato is between 10% and 15%, as the y-axis value of 0% lies in-between the x-axis values of 10% and 15% - from the line of best fit on the graph, I predict the value would be approximately 14%). My results support my prediction insofar as the cells of the potato pieces in water did become turgid, and the cells in a strong concentration of salt solution became flaccid. I didn't make a prediction about specific percentages of salt solution. Evaluation I believe my results are accurate because there does seem to be a continuous pattern between different results, and the spread of the graph appears to be fairly even. I encountered one anomalous result. I recorded no change for the 1st piece tested in 0% solution, when the rest of the results labelled "piece #1" shows a trend, and pieces #2 and #3 are grouped very close together (17mm and 18mm respectively), and piece #1 was out of synch with them, reading 15mm (no change). I believe that the reason for this anomaly is that I cut the piece slightly too short during preparation. Joe Rawson 4/28/2007 Page of 6 ...read more.

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