Undershot Water Wheel example essay topic

A water wheel changes the energy of falling water into mechanical energy that can be used for machines. The water is directed into the wheel through a tube. The wheel is placed on an axle, which is connected by gearing with the machine it is to operate. There are two types of water wheels, vertical and horizontal. The vertical wheels has an overshot and a undershot. The overshot water wheel has buckets around its edge.

Water is delivered to the top of the wheel. The weight of the water falling into the buckets makes the wheel turn. An overshot water wheel has a very good chance of working with a 80 percent efficiency rate. That means, it may turn as much as 80 percent of the energy of the water into mechanical energy. Though, its use is limited to making small amounts of power. The undershot water wheel is built so the water hits the blades at the bottom of the wheel.

The power of the wheel depends on the speed of the water hits the blades. The undershot wheel has such a low efficiency that it is rarely used. Most modern water wheels are horizontal. A horizontal wheel rotates on a vertical shaft.

It is driven by the force of the water hitting the blades on one side of the wheel. Horizontal wheels are very efficient if made correctly. For my experiment I made an vertical undershot waterwheel. For the base of the waterwheel I cut off 8 centimeters of the bottom of a milk jug. Then out of the top of the jug I cut four triangles, four squares and four circles out for the fins of the waterwheel. After that I thumb tacked the 4 triangles to a cork.

Put a hole at the end of each side of the cork and glued a skewer in each side for an axis. Then I cut a hole at each side of the base and put the skewers with the cork suspended in the middle. Then I put a 2 inch x 2 inch piece of clay shaped as circles on each side of the skewer. That's how I got my waterwheel. In my experiment I didn't use electricity instead I measured the rate at which a water wheel lifts a weight. Doing this determined the speed at which the water wheel spins.

For a weight I used a penny that was taped to a string which was wrapped around the clay. Then I poured water onto the water wheel and timed how long it took for the penny to reach the top. Then I changed the experiment a little each time I did it and recorded the effect. The first time I did the experiment it took 5 seconds to reach the top. The second time I did it I added more clay, it took 7 seconds that time. In the third test I changed the clay shape to a square it took 8 seconds.

In the fourth try I changed the shape to a triangle and it took 10 seconds. In my fifth try I changed the clay back to circles and subtracted 2 fins this time the experiment didn't work. In the sixth try I changed the fin shape to squares and it took 6 seconds. On my final try I changed the fin shape to circles It took 13 seconds to rap around the clay. In conclusion the original design worked the most efficient. I think this was due to the amount of the clay on each skewer, the shape of the clay and the shape of the fins.

The trail with two of the fins taken away did not work at all. This was because the space between the fins was too large and only a little amount of water hit the next fin. I thought that the trial with the square fins would work the best but it came in a close second. I think this was because there was too much surface area and the water didn't have anywhere to drain and hit the next fin like the triangular one did causing it to go slightly slower.

The opposite went for the trail with the circular fins, they had too little surface area making the wheel harder to turn. The shape of the clay also took a part in the efficiency of the water wheel. The square and triangular shaped clay both took longer to bring the penny up. I think this was because the thread could not wrap around those as smooth as it did the circular shaped clay..