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Osmosis in potatoes

Extracts from this document...

Introduction

GCSE Biology Coursework An Investigation into osmosis in potatoes Factors that affect the rate of reaction: * Temperature * Surface area * Concentration * Pressure (if reactants are gases) The brief we have been given for this investigation is to examine the osmosis in potatoes. There are many ways in which I could carry out this investigation. One of which is exploring the temperature as a variable. I could bake a potato chip in a sucrose solution at various temperatures and investigate the results. Another possibility is to investigate the surface area, studying various size chips in a continuous strength of solution. The final idea is to consider the concentrations of solution; if I keep the slice of potato the same and control the temperature and time I could look into how the different strength solutions affect the potato. I know that temperature, concentration and surface area can increase a reaction rate by causing more collisions. However, when sucrose solution is heated evaporation would take place, therefore decreasing the amount of water particles so the rate of osmosis would decline. ...read more.

Middle

This is harder to control, and unless I complete the experiment in a hotter environment i.e. the oven I cannot control it. This is most defiantly a flaw in my investigation. For accuracy I have used lids on my dishes to try and reduce evaporation, I have used a percentage increase in my results rather than the weight difference. I have done this because it gives a fairer result because the starting weights are all slightly different. Another accuracy measure I have taken is patting the potato pieces dry after their time in the solution, it removes excess solute so that when weighing we are weighing the solution that has past the partially permeable membrane. I would have liked to use a pipette filer for more precision however they were being used by another class and were not available to me. My hypothesis The solution should affect the rate as a stronger solution would contain less water particles therefore I predict that the higher the solution the smaller the amount of osmosis is taking place. To explain this theory further a high concentration of sucrose solution would have more sugar particles in it than water particles, therefore when a piece of ...read more.

Conclusion

Also my results showing the percentage change follow the trend of my hypothesis, as the concentration of glucose increases the mass of the potato cylinders decreases. The amount of mass lost and gained by the potato cylinders was also fairly consistent, showing that the tests were carried out accurately. After doing my experiment my method proved to be good enough to do what I wanted to do at the start of the investigation. However my method could have been improved by: 1. Carrying out more tests to get more accurate results and better averages. 2. Using a wider range of concentration e.g. 0.1m, 0.3m, 0.5m etc. this will enable me to get much more reliable results. 3. Using scales which give readings to more decimal places. This will give accurate readings and will give me better averages and results. Possible extensions: 1. Investigating other types of vegetables and fruits to see if results are similar. Although I did receive an anomalous result it did not affect my results. They strongly agreed with my prediction and had the correct trend and pattern which also supported the hypothesis which I have already stated. My conclusion and prediction were strongly supported, by the evidence which I collected from my results and averages. ?? ?? ?? ?? Natalie Day 0309 53613 ...read more.

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