Download Daphnia heart rate conclusion sample

My hypothesis was “If I place the Daphnia in the cola water, then it’s heart rate will
increase 10% compared to the pond water because the cola contains caffeine which will make
the heart beat faster. I proved my hypothesis for this lab even though my percentage was a
little off.
Daphina are a small crustacean, they are a member of phylum Arthropoda.In this lab we
measured the heart rate of a Daphnia in plain pond water, which is the Daphnia’s natural home.
The water therefore was the control of our experiment. We counted the heart rate 4 times by
observing the heart carefully under the micorscope and then calculated the average for all the
trials. Our teacher provided us with the data for the Daphnia that was placed in some water that
contained a small amount of cola. The cola was the independent variable of the experiment
because this was what we were testing. The average heart rate of the Daphnia in the plain
water was 140 beats per minute. The average heart rate of the Daphnia in the cola water was
160 beats per minute. The heart rate increased 20 beats per minute when it was placed in the
cola water. This shows a 14% increase. In my hypothesis, I predicted that there would be an
increase of 10% but there actually was a 14% increase in the heart rate. So my hypothesis was
close, but not quite exactly right.
The extension experiment further proves my hypothesis. According to the data, the
more caffeine in the water, the higher the heart rate of the Daphnia went. When the Daphnia
was in water that had only 18mg of caffeine, the heart rate increased very little from the control
But when the amount of caffeine was increased to 80mg, the heart rate increased about 30
beats per minute compared to the control. Then when the Daphnia was ‘placed in water that
contained 200mg of caffeine, the heart rate increased 55 beats per minute.” Our cola water
must have contained similar amount of caffeine as the the experiment in the article. The article
also backs up my hypothesis It states, “caffeine can also raise your blood pressure, increase
your heart rate, and make you feel more stressed, which may eventually lead to heart disease
and other health problems.” This means that caffeine will make your heart beat faster. This was
why the Daphnia in our lab had a higher heart rate in cola because the cola water contained
caffeine. This information is the reason why there was a 14% increase in heart rate in cola
compared to in water in our experiment.
I learned from doing this experiment that cola contains caffeine and caffeine increases
an animal’s heart rate.I notice that when I drink soda with caffeine I sometimes feel “hyper” and I
feel like my heart is beating really fast. The University of Minnesota did a study and found that
30% of 8-13 year olds drink soda each day, which is a lot higher than I thought. In the article it
says that kids may feel the effects of caffeine more strongly than adults because kids are
smaller. This would explain why I feel heart race after I drink soda but it doesn’t seem to bother
my mom. On a really small animal like a Daphnia, just a tiny amount of caffeine increased the
heart rate more than I expected. We learned in science that all living organisms respond to
stimuli. The caffeine is the stimulus and the increase in heart rate is the organism's response.
Also, we did the stimulus lab at the beginning of the year, we learned that stimuli can slow down
the time it takes a person to complete a task. I wonder if a person had caffeine if they would
complete the task faster or if the caffeine would make the person mess up more and take
longer? When I learned about the circulatory system in 4th grade, I learned that my heart beats
to pump blood all over my body. If I drink soda with caffeine in it, this will make my heart work
faster and this is not always a good thing. People can become addicted to caffeine and if they
don’t get enough caffeine, they become sleepy and get headaches. Plus too much caffeine can
lead to diabetes which is also not a good thing. Overall, a little here and there isn’t too bad, but
too much of a good thing can be bad. I will be careful when drinking too much.