Follow these instructions to build a model water wheel project and experiment with hydropower.
Step 1: Cut the bottom from the bottle Measure and mark 8 centimeters up from the bottom of the bottle in 3 or 4 places around the bottle. Then draw a line around the bottle, connecting your marks. Using the craft knife, cut along the line to remove the bottom of the bottle.
Step 2: Cut the middle of the bottle Use the same method and cut an 8-centimeter-wide section from the middle of the bottle. Measure, mark, and cut four 2-centimeter-wide strips from the center section, and use scissors to cut the strips in half so you have eight strips that measure 4 centimeters-by-2 centimeters.
Step 3: Make the wheel Draw 8 evenly spaced lines around the cork and make slits through the lines using the knife. Then slide one of the plastic strips into each slit.
TIP: Make sure the strips all curve in the same direction.
Step 4: Cut the bottom section Measure and mark 2 points on the rim of the bottom section, 12 centimeters apart. Then, measure 3 centimeters up from the bottom of the base section and make a point halfway between the points on the rim. Draw and cut a deep arc from one point on the rim, through the point in the middle, and back up to the second point on the rim.
Step 5: Insert the skewer Poke 2 holes on opposite sides of the base, just below the rim. Then cut the skewer in half and thread each half through one of the holes and into the ends of the cork. Make sure that the skewer halves are wedged tightly into the cork and that they have room to spin in the holes in the bottle base.
Step 6: Attach the other cork Push the other cork firmly onto the end of one of the skewers and tie one end of a length of thread around the cork. Then tie the loose end of the thread to a fishing sinker.
TIP: If you don't have a fishing sinker, you can use another weight.
Step 7: Run the water Put your water wheel in a sink and turn on the water. Watch the water turn the wheel and see if it produces enough energy to wind the string around the cork and lift the sinker. Once you're able to lift the sinker, increase the weight and see how much you have to then increase the water pressure to lift it.
FACT: Hydropower was used as long ago as 100 BCE, when the Greeks and Romans placed vertical water wheels in streams or rivers to grind wheat and corn.