See a picture of the setup of our experiment.
How much air is needed to lift different objects from different depths?
Method and Materials:
50 ft of string
4 milk bottles (for weights)
6 2L soda bottles (3 for lifting, 3 for extra bouyancy)
21 bolts, (10, 7 and 4)
Our experiment was designed to find out how much air is needed to lift three weights from three diffrerent depths. To do this we realized that we would need a platform which we could raise and lower to different depths and would provide us with a place to conduct the experiments. The design we came up was the result of several different ideas that were combined into one. Click here to see a diagram of our experiment and a detailed description. We ended up using the depths of 16ft, 10ft, and 4ft because they were equally spaced and far enough apart to show a difference. Once we had contructed the platform and connected all the weights and bottles we were ready to to our experiment in the pool. In the pool we started at 4ft below the surface and used our purge valves to "pump" air into the bottles. Then we went to 10ft and did the same thing, and agian at 16ft. To measure the amount of air used we took China markers and marked where the bottle was filled up too. See diagram.
We thought that the amount of air you would need to lift up a certian weight would decrease as depth increased. We thought this made sense because the deeper you go, the more dense the water and therefore the more buoyant force. Since this force is higher at deeper depths it made sense to think that the amount of air needed to give the object more of a boost.
Background Essay: (click link)
Analytic Essay (Discussion): (click link)
Here are the conclusions we reached from our data:
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