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Find the rate of osmosis in different vegetables (Carrot, Potato, Swede, Parsnip and Sweet Potato).

Extracts from this document...

Introduction

Freddie Altman Biology Coursework Skill P- Planning In this coursework experiment I plan to find the rate of osmosis in different vegetables (Carrot, Potato, Swede, Parsnip and Sweet Potato). I will measure the mass before and after the experiment to use the results to calculate the rate of osmosis, and to find trends in the vegetables. To ensure the experiment is fair, I will control all the other variables (Temperature, size of chip at 5cm x 1cm, concentration of solution at 0.2M etc.). I will repeat the experiment, and obtain averages for the change in mass. This allows a more accurate analysis to be obtained. Finally I will keep all the vegetables in the solutions for 1 hour, and then repeat this. As there are no dangerous chemicals, or heating taking place, there is no need to wear protective eyewear or overalls. However I will be using scalpels and sharp instruments to cut the chips. This requires general care to be taken, and to work in a clutter-free environment. When I am not using them I will place them away from my experiment and away from others. ...read more.

Middle

This is more than one set of results so it will give more reliable evidence, and allow me to make a better evaluation of the experiment. Results table for mass change: Vegetable Exp. 1 mass before (g) Exp. 1 mass after (g) Exp. 2 mass before (g) Exp. 2 mass after (g) Potato 2.50 2.74 2.73 3.08 Swede 2.67 2.92 2.63 2.88 Sweet Potato 2.39 2.60 2.43 2.69 Carrot 2.71 2.81 2.61 2.84 Parsnip 2.64 2.97 2.41 2.70 Vegetable Exp. 1 mass change (g)/ hour Exp. 2 mass change (g)/hour Average mass change (g)/ hour Potato 0.24 0.35 0.295 Swede 0.25 0.25 0.250 Sweet Potato 0.21 0.26 0.235 Carrot 0.10 0.23 0.165 Parsnip 0.33 0.29 0.310 Results table for percentage change: Vegetable Percentage change in Exp. 1 (%) Percentage change in Exp. 2 (%) Average percentage change (%) Potato 9.6 12.8 11.2 Swede 9.4 9.5 9.45 Sweet Potato 8.8 10.7 9.75 Carrot 3.7 8.8 6.25 Parsnip 12.5 12 12.25 My results are accurate as I used sensitive scales to weigh the chips, so they gave me an extremely exact figure. They also gave me the mass gained per hour on average from the repeat readings. ...read more.

Conclusion

The results were within 0.015g of each other. This would explain the anomaly. When I repeated the experiment the results varied from the previous experiment. This shows that it was extremely easy to make mistakes in the experiment, and that I may not have cut the chips to an exactly identical size. This just proves that the data was unreliable, but still gave an idea of the experiment, and what the results should have been. To improve the method, I would have used a machine to cut the chips to an exact size, along with making sure that all the measurements were correct and accurate. I would also leave the chips in the solution for a longer time, as to obtain better results. This would also reduce risk of errors and anomalies. To extend my work I can do other experiments of a similar nature. For example I could vary the sizes of the chips to see if that affected the results, and also change other variables, which I kept constant in this experiment. April 2004 ?? ?? ?? ?? 1 ...read more.

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Here's what a teacher thought of this essay

3 star(s)

***
A detailed account of the method with clearly presented results. However, only a superficial understanding of osmosis is evident.

Marked by teacher Adam Roberts 10/05/2013

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