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Investigation to see how total surface area is related to oxygen given off.

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Investigation to see how total surface area is related to oxygen given off I will use the following method to obtain the results for my experiment. I will put a certain number of potato cubes into a conical flask. I will then plug the flask with a bung, which has an attached delivery tube. Next I will pour 30cm� of Hydrogen Peroxide into the flask. The Hydrogen Peroxide will react with the enzyme in the potato, called catalyse, to create oxygen. I will wait for an initial burst of bubbles, which is the air being displaced from the conical flask and should not be recorded. After the first bubbles have gone I will put the tube into a measuring cylinder full of water. This cylinder will be submerged in a tub of water. When oxygen comes through the tube it will displace the oxygen in the cylinder giving me an accurate reading of how much oxygen has been produced in the experiment. I will be very careful when conducting the experiment. I will wear safety goggles at all times to protect my eyes from damage. I will handle the Hydrogen Peroxide very carefully so I do not harm others or myself. When using the knife to cut the potatoes I will be very careful so I will not hurt others or myself. ...read more.


* Safety Glasses * Clamp & Clamp Stand * Stopwatch * Ruler * Water Prediction I predict that in my experiment as I double the total surface area of the potatoes the amount of oxygen will double as well. This is because if I increase the amount of potato it should increase the amount of catalyse. When I increase the total surface area of potato in the experiment more catalyse will be present to react with the Hydrogen Peroxide so more Oxygen will be produced. Before I began to collect our data I did preliminary work to decide what our range of results should be. I first decided to test what volume of Hydrogen Peroxide I should use. These are the results for 50cm� of Hydrogen Peroxide for 5 minutes. Number of Potatoes Amount of Oxygen given off (Cm�) 2 50+ 4 50+ 6 50+ 8 50+ 10 50+ Since I am using a 50ml-measuring cylinder using 50cm� of Hydrogen Peroxide is unacceptable since I will not be able to collect results. I then decided to try 30cm� and this generated better results so I decided to use 30cm� in my actual experiment. So I collected more preliminary results with 30cm� of Hydrogen Peroxide instead of 50cm�. Number of Potatoes Amount of Oxygen given off (Cm�) 2 0 4 0 6 6 8 14 10 17 Now I have results that can be used but now they are too close together. ...read more.


There are no anomalous results in my experiments and both sets match up proving to me again that my results are reliable. My method of getting the results could use some work though. Since one side of each potato cube was always touching the glass not all the possible catalyse was available for the Hydrogen Peroxide to react with. This could be fixed by some how suspending the potatoes in the Hydrogen Peroxide perhaps using string attached to the bung. Another problem I encountered was that sometimes the delivery tube would pop out from the measuring cylinder halfway through the experiment and some gas could obviously escaped and not been recorded. The only way I can think of to remedy this problem would to have me constantly hold the tube in the measuring cylinder. Since my investigation spanned several lessons, and because I used large amounts, I used more than one potato. This could be fixed if I found a large enough potato or changed the number of potatoes I used to a smaller amount. A problem I experienced with the larger numbers of potatoes was that they clumped at the bottom of the conical flask. Getting a conical flask with a larger diameter could easily solve this. . To see if there is another relationship, if I had had the time, I would like to have done some intermediate values from my original ones. For example 6,10,14,18 to see if there was a relationship even though there wasn't a relationship in the other ones. Tom Brown May 2003 10D 1. ...read more.

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