Simon Sohn conducted an experiment to test the effect of hydrogen peroxide concentration on the rate of a catalase reaction. He hypothesized that a higher hydrogen peroxide concentration would result in a faster reaction rate and more oxygen production. The experiment involved measuring oxygen production over 1 minute for 3 concentrations of hydrogen peroxide (0.5%, 1%, 1.5%) using a constant amount of liver. The results supported the hypothesis, showing more oxygen produced with increasing concentration. However, the experiment could be improved by standardizing the liver sample size and ensuring it fully submerged in the hydrogen peroxide.

1. Name: Simon Sohn
Enzyme Experiment

3. Name: Simon Sohn
Group members: Misaki, Hiroki
Date of experiment: Dec. 6th 2010
Factors affecting the speed of a catalase reaction
<Concentration of the substrate>
Aim: To see if the concentration of the hydrogen peroxide can affect the speed of the
catalase reaction
Hypothesis: The higher concentration of the hydrogen peroxide, the faster the speed of
the catalase reaction. Thus, more oxygen will be produced during the reaction. This will
happen because more substrates will be there in higher concentration of hydrogen
peroxide, which are to be broken down by the enzyme in liver.
Variables:
Input variable: The concentration of the hydrogen peroxide. I will change it by
using 0.5%, 1% and 1.5% hydrogen peroxide in the experiment.
Output variable: The amount of oxygen produced in the catalase reaction. I will
measure the total amount of the solution (H202+liver+foam).
Control variables:
Control variable 1: The amount of liver. I will keep it the same by using
the exact same amount of liver by measuring its weight.
Control variable 2: The temperature of the hydrogen peroxide. I will
keep it the same by keeping the same temperature in the
place where the experiment is conducted.
Control variable 3: The type of liver. I will keep it the same by using the
same type of liver. (Chicken liver)
Control variable 4: The length of time needed for measuring the catalase
reaction. I will keep it the same by measuring every reaction
for 1 minute.
Control variable 5: The amount of the hydrogen peroxide. I will keep it
same by using the exact same amount of hydrogen peroxide
in each trial. (20ml)

4. Materials:
• 150ml of 0.5% hydrogen peroxide
• 150ml of 1.0% hydrogen peroxide
• 150ml of 1.5% hydrogen peroxide
• 45g of liver
• 100ml Measuring Cylinder (x1)
• Stopwatch (x1)
• Electronic Balance (x1)
• Tweezer (x1)
• Scalpel (x1)
• Dissecting Dish (x1)
• Lab coat (x1)
Method:
1. Cut the liver into smaller pieces with scalpel and dissecting dish.
2. Measure 5g of liver by using electronic balance.
3. Pour 50ml of 0.5% hydrogen peroxide to cylinder.
4. Put 5g of liver into the cylinder.
5. Measure and record the total amount of solution (H202+liver+foam) after 1
minute by using a stopwatch.
6. Repeat the method 1-5 twice.
7. Repeat the method 1-5 three times using 1% hydrogen peroxide instead of 0.5%
hydrogen peroxide.
8. Repeat the method 1-5 three times using 1.5% hydrogen peroxide instead of
0.5% hydrogen peroxide.
Data Table:
Total amount of the solution (H2O2+liver+foam) (ml)
H2O2
Concentration
(%) Trial 1 Trial 2 Trial 3 Average
0.5 29.0 30.0 30.0 29.7
1.0 35.0 37.0 35.0 35.7
1.5 45.0 40.0 38.0 41.0

5. Graph:
H202 Concentra.on .vs. Amount of
Oxygen Produced (Average)
50.0
Total amount of the solu.on
(H2O2+liver+foam) (ml)
40.0
30.0
20.0
10.0
0.0
0.0 0.5 1.0 1.5 2.0
H2O2 Concentra.on (%)
Conclusion:
As it can be seen in the table above, the higher concentration of H202 resulted in
more total amount of solution including H202, liver and foam. My data is reliable
because all the trials in each concentration show increasing total amount, as the
concentration of hydrogen peroxide gets higher. Moreover, the difference between
average values of all three concentrations is 6. Thus, my hypothesis “The higher
concentration of the hydrogen peroxide, the faster the speed of the catalase reaction”
was correct. The higher concentration results in the faster the speed of the catalase
reaction because increasing concentration of substrate in higher concentration of H2O2
increases the chances of substrates to join with enzyme. Thereby, in my case, more
oxygen foam is created in the reaction.
Evaluation:
Errors/Weaknesses in Specific Effect on Improvement to your
Your Method Your Data method

6. 1. In the beginning of the The difference We used 20ml of
experiment, we used between each hydrogen peroxide
50ml of hydrogen concentration didn’t instead of 50ml of
peroxide for each trial. vary much. Therefore, hydrogen peroxide and
However, 50ml of we couldn’t get any this gave the obvious
hydrogen peroxide was pattern or trend. difference of amount of
too much to see the oxygen produced
definite difference between each
between each concentration.
concentration.
2. Livers were cut into Some trials, in which Cutting the liver into as
different size of pieces. comparatively small same size of pieces as
This created more pieces of liver were possible in order to
surface area of liver in put into H2O2, would create same surface
certain trials. In the result in more oxygen area of the liver.
certain trials, the speed produced. In our
of catalase reaction case, the total amount
could get faster. of solution would be
higher.
3. Livers often stuck to When livers stuck to Waiting till liver
the cylinder. It took more the cylinder, it often completely sinks into
time for liver to be sunk resulted in less H2O2, and then starting
into H202. oxygen produced in the timing.
that trial. This error
reduced the reliability
of the data.
Other areas of investigation:
If I get to do this experiment over, I want to change the input variable to different type of
organ. This is because if I use different type of organ as my input variable, this
experiment will give entirely different hypothesis and pattern from previous experiment
with different concentration of hydrogen peroxide. Therefore, I would obtain entirely new
scientific information.