The purpose of this experiment was to determine how much the hydrodynamic shape and mass of an object would affect its velocity when sinking through water.
I became interested in this idea when watching a Discovery Channel documentary on submarines, which must be able to travel through water at high speeds.
The information gained from this experiment can be used to help create new and modified hull shapes for submarines and boats so they can travel more quickly and more efficiently. This will also help architects to design new bridge support columns that will let water flow around them more easily.
My first hypothesis is that a shape with heavier mass will sink at a faster weight than that of a lighter weight in the water tube.
My second hypothesis that that a shape with more streamlined hydrodynamic properties will sink at a faster rate in a water tube.
I base my hypothesis on the physics of aerodynamics and hydrodynamics that say that a more smooth and streamlined shape will be like a wing shape and let more water flow past them easier
The constants in this study were: Same mass in the shapes, same distance to travel, same amount of pressure when it is dropped, same dropper, same water tube.
The manipulated variables were the different shapes of the objects and the mass of each shape.
The responding variable was the speed the objects traveled through the tube.
To measure the responding variable I will have someone drop the object on the count of three and I will start the stopwatch, then stop it again when I hear it hit the bottom of the tube.
1.Make 4 pyramids, 4 spheres,4 cubes and 4 cylinders.
2.Drill the core out of each shape.
3.Fill one of each shape with 30 grams of shot (shotgun shot).
4.Fill one of each shape with 60 grams of shot.
5.Fill one of each shape with 120 grams of shot.
6.Fill one of each shape with 200 grams of shot.
7.Fill all holes with same amount of glue to seal the hole.
8.Fill the tube with water almost to the top.
9.Drop all of the 30 gram shapes one at a time.
10.Record the data.
11.Drop all of the 60 gram shapes one at a time.
12.Record the data.
13.Drop all of the 120 gram shapes one at a time.
14.Record the data.
15. Drop all of the 200-gram shapes one at a time.
16.Record final data.
The original purpose of this experiment was to determine if the shape and mass of an object would affect its freefall through water.
The results of the experiment were that the more streamlined an object is, the faster of rate it will fall through water. The cone fell the fastest because it is streamlined, the cylinder fell the slowest and the cube and spherical shape fell somewhere in between those two. See the table and graph below
My first hypothesis was that a shape with a more streamlined hull shape would sink faster in a water tube.
My second hypothesis was that a shape with more mass would sink faster that a shape with less mass.
The results indicate that this hypothesis should be accepted because the cone sunk at the fastest rate and was the most streamlined shape.
Because of the results of this experiment, I wonder if an object with a larger surface area could ever fall faster that a streamlined shape. This may seem impossible unless the larger object has much more mass than the streamlined shape.
If I were to conduct this project again I would use better shapes for the experiment and use a better water tube than this last time. I would try to find a clear tube to drop the shapes into and I would use a more accurate form of measurement.
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