Dive Group A

Who would have guessed how much one could learn from a crustacean smaller than an ant? As we tested different temperatures on daphnia, we were able to better understand this cold blooded animal. By putting the daphnia in different water temperatures, we expanded our knowledge in countless ways. While conducting our experiment we came up with fascinating results, learned from error, and increased our knowledge of science in general.

Before creating the experiment we predicted exactly what would happen to the daphnia when placed in warm (35 degrees Celsius), control (20 degrees Celsius), and cold (5 degrees Celsius) water. (See hypothesis.) Our predictions were correct for the following reasons. We predicted when we dropped warm water on the daphnia its heartbeat would get faster. After conducting the experiment, we found our hypothesis was correct. The heart rate of the daphnia increased because the blood was circulating through the body faster; therefore the heart was needed to pump more blood throughout the body. When we dropped the warm water on the daphnia, its average heartbeat was 197.5 beats per minute. We were fascinated by the extreme diversity of the results. We did not expect our results to be so drastic, and we learned shortly after dropping cold water on the daphnia how diverse they were. We predicted the daphnia's heart rate would be much slower when put in cold water due to the fact that the blood was not circulating through the body as much. When the daphnia was placed in the 5 degree water Celsius, the crustacean experienced a mild case of hypothermia, and because of this condition many were not able to live. The average heat rate dropped to 142.5 beats per minute. We compared the different results (warm and cold) to the control water results. The control water was 20 degrees Celsius and the average heart beats per minute were 187.4. When comparing the results of the warm water to control water we found the percent of increase was .05%. After we compared the different heart rates of the cold and control water, we discovered an amazing fact. We learned the percent of decrease was .24%. From collecting this data we were able to find where we succeeded in this experiment and where we failed.

Although our experiment was very accurate in many aspects, we did encounter some error. One time we experienced error was when we first began to test the daphnia fish. The moment we received the crustacean, we began to experiment on the daphnia. Some error occurred when the computer would crash in the middle of our experiment. We would be unable to proceed collecting results, and we would have to put another daphnia on the slide. Another error which occurred while conducting this experiment was the daphnia would die as we were gathering the heart beats per minute. We would have to throw that daphnia away and retrieve a new one from the bunch. The one other time when error occurred was when we waited a few days between our experiment. The day we received the daphnia we began the experiment, although that day we were unable to finish. Therefore we waited three days before picking our experiment up where we left off. When we began the lab again, we found it hard finding the last of the daphnia. Many of them were dead due to the shortage of food, and the water they had contaminated with their waste products. Other daphnia had reproduced. We were unable to use the baby daphnia for our hypothermia experiment because, like insects, when daphnia reproduce their offspring are a different life form. A bonus we got out of this experiment was we were able to see the life cycle of daphnia.

After conducting our experiment, we calculated the percentage of error for the test with control, warm, and cold waters. The percentage of error for the control water was 2.7%. The percentage of error for the warm water was 4.39%, and the percentage of error for the cold water was 6.32%. Through all of the error in this lab, we were able to learn more than we ever would have imagined.

Never would we have believed that by creating our own experiment we would have been able to learn as much as we did. We learned about daphnia, hypothermia, conducting our own lab report, and how our experiment related to scuba diving. Daphnia are cold blooded animals. When they are placed in cold water their heart rate drops by approxamently 44 heart beats per minute. When placed in warm water, their heart rate goes up by approxamently 10.1 beats per minute. Hypothermia can be defined as losing heat faster than your body can produce it. We saw this occur when the daphnia were placed under cold water. Originally, we planned on dropping 0 degree Celsius water on the daphnia. We were not able to do this because the moment they were exposed to this cold water, they heart beat stopped, and they died. This happened because they were unable to produce enough heat. This was the first time we conducted a lab report without a teacher's instruction. This resulted in us finding how to teach ourselves many new things. We learned how to use the computer camera, the microscope, thermometers, and how to regulate water temperature. This experiment was related to scuba diving in many ways. Although we used cold blooded animals for our experiment, the results on humans would be similar. If the water one is in is 60 degrees Fahrenheit, and one quickly drops to water 20 degrees Fahrenheit, your heart rate will have a similar affect as it did on the daphnia. Scuba divers must be aware, when descending, about the effects of hypothermia on their body.

In conclusion, our experiment was successful in proving the concepts we were testing. At the beginning we created an experiment not having any expectations it was going to work or be educational. Yet, we were not only able to learn from our teachers and our results, but we learned the most from ourselves; this is what made our experiment successful.

 Background Essay

 Method and Materials


Lab Report

Analytic Essay










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