Lab Report
Research Question:
How does catalase work differently in a raw, baked, and frozen potato?
Hypothesis:
If the raw, baked, and frozen potatoes are subjected to hydrogen peroxide, the baked
potato will produce the tallest amount of bubbles because heat speeds up reactions.
Variables:
Independent variable- the temperature of the potatoes; raw, baked, frozen
Dependent variable- the height of bubbles formed; in cm
Control group- the raw potato (temperature is closest to body temperature)
Constants- temperature of room, size of potato chunks, type of potato, amount of
hydrogen peroxide, and time measured in minutes
Materials:
- 3 potatoes (1 raw, 1 baked, 1 frozen)
- Knife
- 1 graduated cylinder
- Scalpel
- Hydrogen peroxide bottle
- 3 test tubes
- Ruler
- Wax crayon
Procedure:
1. Take one raw potato and cut it into three 1cm x 1cm pieces using a scalpel and
place the pieces into three separate test tubes.
2. Pour 5 mL of hydrogen peroxide into the graduated cylinder, then pour this
amount into each test tube containing the piece of potato.
3. Record the initial amount and the height(volume) of bubbles formed from the
reaction in a 1 minute time frame using a ruler. Mark the height of the bubbles
formed on the surface with the wax crayon.
4. Subtract the original height of the hydrogen peroxide before the bubbles formed
from the total height to find the height of the bubbles. Record the heights.
5.
Wash out the utensils used.
6. Repeat steps 1-5 with a baked potato.
7. Repeat steps 1-5 with a frozen potato.
Data Table:
X= temperature of potato
Y= height(volume) of bubbles formed
Raw
Baked
Frozen
Trial 1
1 cm
0cm
1cm
Trial 2
1cm
0cm
.5cm
Trial 3
1cm
0cm
.5cm
Average
1cm
0cm
.7cm
Graph:
Conclusion:
In the Potato/Catalase Lab, our group hypothesized that if our baked, raw, and
frozen potatoes are subjected to hydrogen peroxide, we predict that the baked potato
will produce the tallest amount of bubbles because heat speeds up reactions. To test
this experiment, we measured the height, or volume(mL) of the bubbles formed by the
catalase and hydrogen peroxide reaction, by using different potato temperatures; raw,
baked, and frozen. We measured this over a 1 minute time frame for each of the 3 trials.
First, we placed a 1cm x 1cm piece of each potato inside a different test tube and
poured 5 mL of hydrogen peroxide into each test tube. We found that the our hypothesis
was incorrect - the raw potato ended up producing the tallest amount of bubbles, rising
from the surface of the hydrogen peroxide to 1 centimeter above. Only the surface was
affected and the potato was left untouched in the reaction. The baked potato’s reaction
with the catalase did not produce any bubbles, meaning the catalase was not working
properly. There was no bubbling on the surface or around the potato, while the particles
of the potato were separating. For the frozen potato, the average height of the bubbles
formed was approximately 0.7 centimeters. The whole solution bubbled, including the
hydrogen peroxide around the frozen potato, and the surface. Contrary to what we had
predicted, the control group (raw potato experiment) ended up having the biggest
reaction; the bubbles thickened and grew even after the designated one minute per
potato experiment. These results might be due to the fact that enzymes don’t function
well once they reach temperatures that are too cold or too hot; they need to be in a
certain temperature range to make a reaction, for example a temperature closest to
body temperature, as was the raw potato. Therefore, the baked potato probably had no
reaction because it had exceeded the amount of heat which caused the enzymes to
denature, while the cold just slowed the reaction down. From this lab, we learned how
enzymes function under different temperatures and make reactions. Despite our
acquired knowledge, we made a few errors in our experiment. We sometimes poured
different amounts of hydrogen peroxide due to the different sizes of the potatoes. We
cut the potatoes into different sizes because it would have taken too much time to cut
them into perfect squares, and too much effort, since potatoes have different shapes.
Also, using the ruler was a bit difficult since the bottom of a test tube is rounded,
meaning we couldn’t tell if we were measuring from the very bottom of the test tube.
Therefore, our measurements might have been a little off. Our experiment was limited
because there were a few factors that affected the outcome but weren’t planned or
controlled. For example, the fact that potatoes contain catalase but don’t contain the
same amount as in the human body was a limitation, and it would be too dangerous to
test this experiment in a human body. Organization for our group was a limitation,
because having no prior experience with organizing our own lab, we misplaced
potatoes, test tubes and other supplies, while being messy. We didn’t carry out the
experiment in the order of the procedures, starting with one potato experiment and
going to too many. Overall, our group felt that this lab and experiment was a great
learning experience.
Top left: Frozen potato
Bottom left: Frozen potato
Top middle: Baked potato
Top right: Baked potato
Bottom middle: Raw potato
Bottom right: Raw potato