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An investigation into the factors affecting osmosis

Extracts from this document...

Introduction

Planning My aim for this experiment is to see the results of potato tissue's mass difference, when placed in different concentrations of sugar solutions. Variables involved: For this experiment I would expect to have 3 different variables, Independent, Dependent, and fixed variables, which all helps me to plan and explain the experiment thoroughly. The Independent variable (things you change), the thing that I will be changing in this investigation into the factors affecting osmosis, is the concentrations of the solution that helps me to investigate osmosis with potato tissues. The different sugar concentrations will be changed to see the result of the potatoes when placed in sugar solutions placed in different molarities (strengths). Dependent Variable (things that you measure) the things that I'll be measuring in this experiment on osmosis is the mass change and length change of the potatoes placed in different molarities of sugar solutions. I will record the masses in grams by using a balance and the length changes by using a ruler. Fixed Variables (Things that you keep the same) the things that I have chosen to keep the same in each individual experiment to keep it a fair test is to keep the same sizes of each potato tissue the same by using the same cork borer and same ruler. I will be keeping the same amount of solution placed in the test tubes for each different experiment, which I will measure using a measuring cylinder. I will also be keeping the same potato through out the whole experiment to as using a different one might give me anomalous results as some might have more water in it then others. Preliminary work: For our preliminary work we looked at how the different molarities of solution affected the amount of osmosis in onions, and we found out that 0 and 0.1 molar solutions had increased greatly in size and mass. ...read more.

Middle

5: Contamination: As each test tube is filled up with the different molar solutions the syringe which would measure the amount of solution placed in the test tube may become contaminated with different molarities. To stop his from happening, the beaker and syringe must be washed every time they are used. 6: Average: To make the experiment as accurate as possible an average will be taken out of the 6 sets of results taken. Also any clearly anomalous results will be ignored. 7:Temperature: The temperature may affect the reliability of the experiment for example at extreme temperatures the cells of the potato may die and at less extreme temperatures the experiment may be speeded up. To keep this from happening, all the test tubes will be kept in the same place and at the same time of the one-hour experiment. Safety procedures: Safety is an important aspect in every experiment, even if the experiment seems to be very harmless. This is why I'll be taking this into consideration. I will be using a very sharp knife, which could injure someone if it's not handled properly. I will also be very careful that the solutions don't get into our bodies internally, just in case, because we are not fully aware of the damage it could do to us. I will also be wearing an apron due to any solutions getting to my clothes. But other than that, there weren't any bigger matters to be cautious of. Method: I plan to carry out this experiment by using all the safety issues and fair testing procedures to give me the most reliable and most accurate set of results. I plan to have a range of sugar solutions prepared with concentrations from 0.2M to 0.4M, in intervals of 0.04. Then sections of potato will be cut using a cork borer and knife to lengths (between 5omm and 60mm) ...read more.

Conclusion

The original results detract from the firmness of the conclusion because of the anomalous results and the fact that they reduce the reliability of the experiment. However, the conclusion can be said to be firm because both the experiments supported the statement and the repeat run firmly indicated that the conclusion was entirely true. Improvements and Further Work: There are number of alterations and improvements that could be added to the method which would allow us to investigate further into the area of osmosis in biology. -You could investigate osmosis further by seeing the effect of concentration of different types of potatoes or using entirely different plants (e.g. plants, other vegetables, fruits or a different type of potato). This would test how different semi-permeable membrane could affect osmosis and the movement of water out and into organisms. -You could investigate the time it would take for potato cells to plasmolysise. I.e. you could investigate using extremely low or high concentrations with potatoes. This would allow you to see how long it would take the potato to plasmolysise and die. -You could do the experiment using a longer period of time for osmosis to occur. By doing this you could investigate how long it takes for osmosis to fully complete. It could also be connected to the above improvement in finding how long it takes for the potato cells to plasmolysise. E.g. use a 3-hour or longer 24-hour period. -You could do an investigation into how changing surface area and the amount of solution affects the rate/how long it for osmosis to occur. -You could do an investigation into how osmosis is affected when it occurs it different conditions, i.e. how osmosis occurs under high or low temperatures. You could also investigate the amount of heat that the semi-permeable can withstand before the membrane is disrupted. After this you could expose the potato to a certain amount of heat, a large amount (but not enough to completely disrupt the membrane) and then you could see how exposing the potato to heat beforehand affects osmosis. ?? ?? ?? ?? ...read more.

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Here's what a teacher thought of this essay

4 star(s)

This is a well written and detailed report.
1. The variables sections cover the necessary information and set out the investigation well.
2. The report is missing an introduction section with relevant information. This information is scattered in other sections of the report.
3. The scientific information section contains relevant information that should be referenced.
4. The table of results is well presented.
5. The analysis summarizes the data but does back this up using the data itself.
6. The evaluation shows a good knowledge of scientific processes.
****(4 stars)

Marked by teacher Luke Smithen 08/05/2013

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