As you may remember, Amy was locked in her lab last month, feverishly working on her science fair project. Now, the results are ready to be seen. Take a look at Amy's work.
For the science fair, I've chosen to experiment with evaporation. To do this, I've explored heat and its affect on evaporation rates when water is placed under different wattage bulbs.
For the experiment I used four different watts: a twenty-five watt bulb, a forty watt bulb, a sixty watt bulb, and a seventy-five watt bulb. Each bulb was placed in a rubber light socket and attached to a box where it hung over a glass of eight oz. water.
I decided to do this experiment because of an occurrence at my camp. I go to seven weeks of camp in Belgrade Lakes, Maine. This past summer, the water level of the lake was the lowest it's been since I've been there. We also had only three rainy days the whole summer. Since heat energy causes evaporation, I wanted to know if the great amount of sun had to do with the lack of water in the lake.
My hypothesis was that the seventy-five watt bulb would cause the most evaporation. The reason for my hypothesis is this. All substances have molecules. These molecules have a certain amount of kinetic energy. The more kinetic energy molecules have, the faster they move allowing them to break free of the bonds that hold them together. Evaporation takes place when molecules of a substance have enough kinetic energy to escape from the substances surface. Kinetic energy comes from heat. Therefore, the more heat a substance obtains, the more kinetic energy it has which causes evaporation. Another way of saying it is, the higher the temperature, the more rapid the evaporation.
This photo shows how the boxes looked in the
This photo shows how the boxes looked after
the thirty hours passed:
This photo shows the control box with
There are a few possible errors in my science fair project. The lights could have been at a slightly different angle. This could have effected the amount of heat on a glass of water compared to another. Another possible error is that when pouring the water back into the measuring cup, a little water could have been left over. Even though this could of happened, it would be such a tiny bit of water that I don't think it would have effected the overall results.
I could have improved my experiment by adding a couple more wattages. That would have helped my results even more. I tried to do a one hundred watt bulb, but the socket started to melt and we didn't want the house to burn down! Another way of improving my experiment would be to use actual measuring glasses instead of cups. Then I could have taken daily observations of the actual evaporation.
One new question formed in my head while I was doing this experiment. Another idea is to not only test the evaporation of water with different wattage bulbs, but you could also test the angles of which the bulbs are placed. Then you could use it as a replica of the sun and see what time of day the most evaporation takes place. That would be most interesting.
My hypothesis was correct. The seventy-five watt bulb caused the greatest amount of evaporation. In the first test, there was five and one-half ounces of water left. In the second test, there was five and one- quarter ounces of water left. In the third test, there was five and one -quarter ounces of water left. In the fourth test, there was five and one-half ounces of water left. In the fifth test, there was five and one-half ounces of water left. Over all the average rate of evaporation was 2.6%. The average rate of evaporation for sixty watt bulbs was 1.85%. The average rate of evaporation for forty watt bulbs was 1.65%. The average rate of evaporation for twenty-five watt bulbs was 1.45%. It is obvious that the seventy-five watt bulb caused the most evaporation. This is because again, the more heat a substance has, the more kinetic energy and it is kinetic energy which is the cause of evaporation.
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