The Effect of Hull Shape on Speed Through Water
Researched by Kyle W. 2001-02	PURPOSE  HYPOTHESIS  EXPERIMENT DESIGN  MATERIALS  PROCEDURES  RESULTS  CONCLUSION  RESEARCH REPORT  BIBLIOGRAPHY  ACKNOWLEDGEMENTS  ABOUT THE AUTHOR

PURPOSE

The purpose of this experiment was to determine which three-dimensional shape went through water the fastest.

I became interested in this idea when I saw a TV show about submarines and wondered why they were shaped the way they are.

The information gained from this experiment would help people who design submarines and boats to see which shape is the most hydrodynamic. 

My hypothesis was that the egg shape would go through the water fastest and that the cube would be slowest. 

I based my hypothesis on the fact that submarines are made in an egg shape so it must be the best shape, and because the end of the egg has the least amount of surface area and would have the least amount of drag. The cube has a lot of surface area so it would make lots of drag and go slowest.

My second hypothesis was that the smaller shapes would go faster than the big ones because they create the least amount of drag.

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The constants in this study were: 
* The amount of water
* The height the shape was dropped from
* The stopwatch and method of measurement
* The tube that the water’s in 
* The material that the shapes were made of 
* Density of the shapes

The manipulated variable was the shape of the objects.

The responding variable was the speed that the shapes traveled through the water.

To measure the responding variable as I dropped the shape into the tube, the 2 observers started the stopwatch, then when they saw it hit bottom they stopped the stopwatches.

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MATERIALS
 

QUANTITY	ITEM DESCRIPTION
1	4.2672 meters PVC pipe, 10.16 cm wide
1	Egg Shape (wood)
1	Cube Shape (wood)
1	Sphere Shape (wood)
1	Sm. Sphere Shape (wood)
1	Sm. Cube Shape (wood)
1	Spool Shape (wood)
4	4.8768-meter strands of dental floss
2	Stopwatches
1	Displacement Container
1	Graduated Cylinder (100 ml.)
1	Triple Beam Balance Scale
1	Pack Assorted lead Fishing Sinkers
6	Eyelet Screws
1	Drill

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1. Obtain all materials.
2. Screw an eyelet screw into the shape, at the trailing end of the shape.
3. Find the density of each shape.
a) Drill a hole in the shape (size according to the amount of lead needed) cover with tape.
b) Fill displacement container 100% full of water.
c) Slowly submerge the shape 100%.
d) Measure the water displaced with graduated cylinder.
e) Find the mass of the shape with a balance scale. 
4. Make shapes density = 1.5grams/cm3 by taking (1.5 X shape’s current Volume - the shapes current mass) to find mass of lead needed in shape.
5. Melt and add the amount of lead needed and then cover the lead with acrylic. 
6. Tie a piece of dental floss to the screw.
7. Stand up the tube. (PVC)
8. Fill up the tube with water, within 15cm of top.
9. Grab the end of the line.
10. Drop the shape into the tube; be sure to have fishing line feed out smoothly.
11. When you drop it have some one start the stopwatch.
12. When they see the shape hit the bottom stop the watch.
13. Then pull up the shape with the fishing line.
14. Record the data.
15. Repeat steps 2-6 for all the shapes.
16. Repeat steps 9-15 10 times for each shape. 

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The original purpose of this experiment was to determine which three-dimensional shape went through the water the fastest.

The results of the experiment were that the small sphere went the fastest at 8.46 seconds, but the egg was only 7 tenths of a second slower at 8.53 seconds. It also showed that the cube was the slowest shape at 15.27 seconds. 

See data and graphs 

My first hypothesis was that the egg shape would go through the water fastest and that the cube would be slowest. 

The results indicate that this hypothesis should be rejected, because the egg was 0.7 seconds slower than the small sphere.

My second hypothesis was that the smaller shapes would go faster than the big ones because they create the least amount of drag.

The results indicate that this hypothesis should be accepted, because the big cube took 15.27 seconds while the small cube took 11.95seconds. Also because the big sphere took 14.20 seconds and the small sphere took 8.48 seconds. 

Because of the results of this experiment, I wonder if I used a lesser or higher density for the shapes if the results would be the same. Also if I used a lesser\higher density of liquid.

If I were to conduct this experiment again I would conduct more trials, a better way to measure the times.  I would also have a more precise scale to weigh the shapes. Also I would repeat the experiment over again.

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Report Introduction          Transportation is very important to humans to move things, like food, fuel, and medicine, sometimes long distances. In the water there is more drag than in air so vessels need a more hydrodynamic shape to go faster and transport things efficiently.  Water Water is a liquid made from of hydrogen and oxygen. In one water molecule there are two hydrogen atoms and one oxygen atom. Water helps keep all living organisms alive. The human body can only live for about three days without water or it will die. Water can be found in three different forms: gas, liquid and as a solid. If the water is in its liquid form it is like the water that we drink and the water in the ocean. Air contains water vapor, its gas form. Ice is the solid form of water.  Water Cycle Water has existed for millions of years. If water is sitting in the ocean, some evaporates. Then it forms clouds and when the clouds get cold and condense they precipitate and the same water originally from the ocean rains down into a river then flows down the river to the ocean. Some can just land in the ocean. Then the same process starts over again. This process is called the water cycle. Pollution Pollution is a very bad thing for the environment. It can be especially dangerous to humans who need to have pure water and food or they can get diseases like cancer. If a person is pregnant pollution can cause birth defects. The major types of pollutants of water are man-made chemicals, biological wastes, or physical materials. The cause of almost all of these things is humans. If a tanker spills oil into the ocean it can cause major effects on the animals in the water. They can die because their fur can bunch up and they will die of hypothermia or they can ingest the polluted water and end up poisoned or getting a very bad disease.  Submarines A submarine is a ship that operates under water. It is made of steel and titanium. The metal used for it is very thick, to withstand the water pressure. They can travel at a speed of 40 knots because of their long, cigar shape. The most modern subs now run on nuclear energy but the older subs run on diesel on the surface and batteries under water. Attack subs may have torpedoes, mines, antiship missiles, land attack cruise missiles and ballistic missiles with nuclear warheads. Another type of submarine is the scientific research sub that goes slower than the attack subs and has lots of research instruments instead of weapons. History   The first subs were made about 500 years ago. They were wooden rowboats with leather covering over them. In the 1700’s through the mid 1800’s people improved from the rowboat but it was still hand powered. By World War I most countries had a small fleet of crude but effective electric submarines. In World War II the submarine played even a bigger factor than in WWI because of their increased speed and long range shooting.  In 1954 nuclear power was introduced to the submarine. It made them even faster and able to travel a very long way under water. Friction and Drag Friction is when two surfaces brush against each other and create heat and slow the objects down. Friction wears down objects but also makes us able to walk. Without friction it would be like walking on ice. To reduce unwanted friction in machines people apply lubricants such as oil or grease. You can also reduce it by sanding the object. You can never stop friction completely. There are three kinds of friction. The first one is rolling friction. This is produced when a rolling object goes over something, like a soccer ball. The next one is sliding friction; it is when two things move across each other, like when you are sanding something the friction makes the object hot. The last one is fluid friction; it’s the force between a fluid and a solid, such as water flowing through a pipe.  Drag Drag is a frictional force that acts between an object and a fluid. Drag is a force that slows vessels in water and planes in air. The amount of drag depends on the shape, size, and weight of the object and the viscosity of the water or fluid. Viscosity is the thickness of the fluid that the object is traveling through. If an object has with a point, the shape has less drag because the point of the shape will cut through the water. But if you have a shape that doesn’t have a point, like a cube, will not go as fast because the flat part will not cut through the water and then the shape will slow down. Top of page

BIBLIOGRAPHY Benford, Gregory."Friction." World Book Encyclopedia. 1999. "Fluid Flow." World Book Encyclopedia of Science. "Fluid Mechanics." Microsoft Encarta Suite, 2001. Johnson, Clifford V."Friction." Microsoft Encarta Suite, 2001. Offley, Ed. "Submarines," Microsoft Encarta Suite, 2001 Polmar, Norman. "Submarine." World Book Encyclopedia.1999.

ACKNOWLEDGEMENTS
I’d like to thank the following people. Without their help my project wouldn’t have been possible.

* My Dad for helping me with all of my experiment including melting the lead, drilling hole and timing the shapes.
* My Mom for helping out with the recording of the data and dropping the shape.
* My Little brother for helping out with the timing.
* Landin and Aaron for helping me by listening to my presentation.
* Mr. Newkirk, helped me with everything from correcting my report to staying after school to help me with my project.
 
 
 
 

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