Renewable energy sources are the face of today's green movement, but water turbines or water wheels have been around for centuries. Create a model at home to understand the power produced by water turbines, and to test one for yourself.
- Skill level:
Things you need
- 2 litre plastic bottle
- Razor blade
- Barbecue skewer
- Washer weight
Wash out the bottle and remove all labels.
Cut the bottle with a razor blade above and below the labelled area. This divides it into three parts: the mouth to neck, the middle area (where the label was), and the bottom.
Cut the middle section of the bottle into eight equal rectangular sections. These will become the spinning blades of the turbine.
Slice eight incisions around the circumference of the long side of the cork with the razor blade. Make sure they are equally spaced and the length of each of the long sides of the plastic strips.
Insert the plastic strips into the cork about 1/8 of an inch deep. The cork should resemble a water wheel or turbine at this point. Position the plastic strips so that they all curve in the same direction.
Make a V-shaped cut out in the bottom section of the bottle, beginning at the cut edge and moving down, so that the smallest section of the V ends 1 inch or more above the curved base of the bottle. This spout-like cutout will allow the water you pour into the bottle to stream out.
Push the barbecue skewer carefully through the top centre of the cork turbine you prepared earlier. Corks can be fragile, so do not rush this step. After you have pierced the cork, remove the skewer.
Pierce two matching holes on opposite sides of the plastic bottle bottom with the skewer. Make the holes parallel to the V-shaped cutout.
Insert the skewer halfway through the plastic bottle bottom, then slide on the turbine.
Slide the skewer through the rest of the bottle and out the other side. The plastic blades should slope down toward the V-shaped cutout.
Tie one end of the string to the washer weight and the other to the sharp end of the skewer. The string should be about a forearm's length or longer.
Suspend the base of the bottle on the edge of a chair or table outdoors. Drape the string with the weight at the end over the edge of the table.
Pour water from a full pitcher over the turbine. The turbine should spin with the water, and the weight of the falling water should lift the washer weight up in the air.
Tips and warnings
- Try this experiment a few times to make sure you've got it right, especially if you are working on it for a classroom setting.
- If you will perform the experiment in class, use a large tub or sink to catch the flow of water from the spout.
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