Through our studies of hydrodynamics, our tests, and our experiments, we learned about which shapes and sizes will travel through water the best. This is very useful because it helps us make educated guesses on how other objects may move. Also, if you understand hydrodynamics, it can help you realize why people build boats and submarines the way they do. We now understand that streamlined objects will have betterhydrodynamics. We also learned how we can reduce drag on objects, and how angles will affect velocity and direction of objects. Our studies of hydrodynamics also help us understand why various sea life is in the shape and size they have evolved into now. For example, a shark’s body structure is a tear-drop shape. With fins, and a large tail, it can travel through water very effortlessly. It has an angled nose to decrease the drag that could slow the creature down. Furthermore, hydrodynamics helps us understand principles about water dynamics and how different shapes, volume, and weights work better than others.

    Error


In our experiment, we calculated a very small percentage of error. For the cylinders, the average percentage of error was 1.56%, while the rectangles averaged 1.31% error. Fortunately, the error did not effect the results. The first possible source of error was human related. In our project, a human would start and stop the timer when the object started moving and when it broke the surface. It is difficult to judge the correct time. As a result, the times we calculated may not have been exactly correct. Another error we learned about was friction. In our experiment, we used fly line to pull the test objects up. The line had to go through wood, and eye hooks. These materials that the line went through created a small amount of friction on the line. On the top of each object was a small hook, attaching the test object to the line. This hook might have slowed the object from getting to the surface, although every test object had the same hook. These were the main errors we identified in our project. Even with these possible sources of error, our data was very accurate.

    Our project was designed to show us what shaped object will move the fastest through water. In other words show which shape has the best hydrodynamic design. We used six objects; three cylinders, and three three dimensional rectangles. One cylinder and one rectangle had a zero degree angle, one cylinder and one rectangle have a thirty degree angle, and one cylinder and one rectangle have a 45 degree angle. In order to give them each the same buoyancy, we screwed on various amounts of washers to the bottom of the objects. Each object had to have the same buoyancy to remove the effect of buoyancy from our data. The washers added weight to the test objects so they could sink. In our project we had a base that hung out over the edge of the pool. On it there was three eye hooks with fly line going through it. On each side of the fly line here was a weight and on the other side one of the six test objects. When we let go of the weight from the top of the water it dropped and one of the objects was pulled to the top. The time measured how smoothly each of the objects cut through the water.

   

    After each object was tested in the pool, we found out that the cylinder with a forty five degree angle traveled up the fastest. It traveled through the water at a speed of 6.265 feet per second. No other object surpassed that speed. Overall the cylinders traveled faster when you compare the average speeds to the rectangles with the same degree of angle. The average speed for cylinders is 5.725 feet per second, while the rectangles traveled at an average of 5.55 feet per second. The 45 degree angle cylinder encountered the least amount of drag due to its angled point. The cylinders are more streamlined than rectangles.

 

    The overall design to the experiment in our opinion was very reliable. However, if we were to change anything, we would buy the same type of wood for all our test objects. This is because the two different kinds of wood we bought were very different in density, and made it more difficult to add weight to give each object the same buoyancy. We would also change the device that stopped the objects after they broke the surface. The device we used was difficult to make, and time consuming. The original one we used we had to make from scratch with bad wood. It involved us manually sawing it, drilling a lot of holes, and manually screwing it on. The main problem was we did not have some tools we would have liked to have. I would buy an object that could do what we wanted it to do. I would go to a local hardware store to have the object all ready and save that time. After that I would screw it on to the apparatus. That would have been a lot easier than manually sawing the wood, drilling the holes, and screwing it on. That is what we could have changed to make the project better.