Procedure
Procedure
- Take your scissors and cut out the flat bottom part of the aluminum pie plate.
- With the permanent marker, copy the design of a waterwheel template onto the circle of aluminum. Draw the lines from the edge of the circle to about 2 centimeters (cm) from the middle of the circle.
- Cut the aluminum circle along the eight solid lines. End each cut at 2 cm from the center. These are the paddles of the waterwheel.
- Carefully bend each paddle at its dotted line. Put the ruler at each dotted line so that you can make a straight bend. This waterwheel has eight paddles. Bend each paddle at its dotted line.
- Drill a 5/16-inch hole through the middle of the waterwheel. You could also use a hammer and nail to make the ¼-inch hole in the middle. If you use a hammer and nail, clip off any sharp metal edges around the hole with the scissors.
- Glue the nylon spacer to the middle of the waterwheel. The nylon spacer stiffens the waterwheel. Here is a completed waterwheel.
- Wait until the glue is fully dry before continuing. Consult the packaging of the epoxy for drying times.
- After the glue dries, use thin strips of Scotch tape to secure the nylon spacer to the waterwheel. Make sure that the hole in the center is not covered with tape. Set the waterwheel aside.
- Remove the handle from the bucket. Now drill two 3/8-inch holes where the ends of the handle use to be. Make sure that the wood dowel can fit comfortably through the holes and spin freely. It should not be a tight fit.
- Wind a piece of Scotch tape around the middle of the wood dowel. This is to add some thickness in order to keep the waterwheel in place. Now insert the dowel through the holes of the bucket. Move the dowel out of one of the holes and carefully slip the waterwheel onto the dowel over the piece of tape. Reinsert the dowel through the hole in the bucket. Turn the waterwheel and make sure that the wood dowel turns as well. If the dowel doesn't move, you should gently move the waterwheel off of the tape and wind another piece of tape over the original piece of tape to add thickness so the two objects move at the same time. The waterwheel must sit tightly on the dowel so that when the waterwheel turns, the dowel turns.
- Take the cotton string and tie one end to the metal nut. Tie the other end of the string to one end of the wood dowel, outside of the bucket. Tie the end such that when the dowel starts to turn, it immediately starts to wind up the string. You need to pay attention to how the waterwheel turns to do this; either clockwise or counterclockwise.
- Wind some tape and make a little tab (by folding the end of the piece onto itself) on the dowel outside of the bucket on both ends so that the waterwheel and dowel don't move horizontally too much—you don't want the dowel slipping out of the holes. The waterwheel should be sitting in the middle of the bucket and should be able to turn freely, without hitting the bucket. Now you are ready to start converting the kinetic energy in falling water to mechanical energy.
- To do these experiments you can use any source of moving water, like a sink or bathtub faucet, or an outdoor hose.
- Pick a water source where the water comes out in a steady stream. Do not use a water source where the water is a wide, cone shaped spray it will lead to poor results. For example, a shower head would not be a good water source. If you are using a hose with several different nozzle settings choose the setting that is least like a shower and most like a steady stream.
- Using the measuring cup and the stopwatch, first calculate the flow rate of the water source you are using. You will do this by seeing how long it takes to fill 2 cups of water. Note this time down in your lab notebook in a data table like the one below.
- Divide 2 cups by the number of seconds it took to fill 2 cups. This is the flow rate and its unit of measure is cups per second. Note down the flow rate in your lab notebook.
- Do not turn off the water between measuring the flow rate and testing the waterwheel or else you will have to redo the flow rate calculation (you might turn the faucet on harder or softer the next time, which would negatively affect your results).
- Make sure that the string and weight are unwound before you begin. Place the waterwheel under the flowing water. Measure the height of the flowing water with the ruler. Record this information in your lab notebook. Using the stopwatch, time how long it takes to wind the weight up. Note this time in your lab notebook.
- Repeat this measurement two additional times at the same water height and record the information in your lab notebook.
- One thing to keep in mind is to not let the bucket get too full of water or else the bucket water will get in the way of the waterwheel.
- Note: Make sure that the water hits the waterwheel in the same spot for every trial. The waterwheel should go either clockwise or counterclockwise each time. Record all information in your lab notebook.
- Now you do want to change the flow rate of your water source, so adjust it and repeat steps 13 and 14. Make sure that the trials are all done at the same water height. Change the flow rate one more time and repeat steps 13 and 14 again. So you should have three trials each for three different flow rates.
This is the final product.