Despite a little confusion at Long Beach, our experiment was a success. As you probably know, our problem statement was “How does an object’s shape affect its drag and Hydrodynamics?” We tested this by pulling different shaped objects through a PVC pipe. To do so we had a pulley on one end with the control weight, a six ounce sphere. attached to a string. The weight on the other end of the tube was changed to test our problem statement. We had three weights to test. Weight 1 was a one-pound sphere. Weight 2 weighed one-pound and had a blunt front and curved back. Weight 3 weighed one-pound and was shaped like a submarine. This was our hypothesis: weight 3 will have the fastest time, weight 1 the second fastest, and weight 2 the slowest. Here is our graph to illustrate this information


 

 

 

 

 

 

 

We found, however, that our prediction was close, but not quite right. We predicted that weight 2 would be the slowest. In fact, it was the fastest. While talking about our hypothesis, I had ventured that weight 2 could conceivably be the fastest. We thought that the rounded end might push the water behind it. But we couldn’t explain it well, and we didn’t really believe it would have the least drag. Whether our reasoning was true or not, we were surprised to find that it had the quickest time of all three weights. Our initial reasoning for putting weight 3 as the most hydrodynamic was its resemblance of a submarine. The fact that almost all submarines are shaped like that, and considering that submarines depend on minimal amounts of drag, we figured that the engineers must have a very compelling reason for shaping them that way. Here is our result table for our average times for each weight.


 

 

 

 

 

 

 

As you can tell, weight 2 had the least drag, weight 3 the second least, and weight 1 the most. We had thought that the object with the least frontal surface area usually had the least drag, but weight 3 had an area of .5625 sq. in. while weight 2 had an area of 1 sq. in. We suppose that the frontal surface area is not the only factor in hydrodynamics.
Our only regret about the experiment is that we only used three weights. We tried very hard to get more weights, but all the stores only had three choices. We called five different fishing stores, but none of them had a large supply of one pound fishing weights.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Background by Nora

 

 

 

 

 

 

 

 

 

 

Analytic Essay