This windmill science project article contains instructions for building a windmill science project from Tinkertoysâ„¢and information on a number of extensions to expand students' understanding of how windmills work.

Build a Windmill

In this project, students make a simple model to demonstrate the greenhouse effect. This project requires a sunny day.

Materials

•  Assorted Tinkertoysâ„¢ including eight of the green trapezoids to use as blades.
•  Assorted paper, cardstock, cardboard, and plastic to use as blades
•  Balsa wood to use as blades
•  A small household fan
•  Scissors or a cutting blade
•  Watch or timer

Directions

1. Use spools and rods to construct a square base.

2. Use this base as the foundation of a tower, with the four corners at the top of the tower all being attached to a central spool.

3. Use the central spool as the base for the windmill apparatus:

• Place a fairly short rod in it, with a spool attached to the top of the rod by one of its edge holes (not its central hole).
• Place a medium rod firmly in the center hole.
• Slide a spinning spools central hole over the end of the medium rod, and cap the rod so the spinning spool can't fall off.
• Using orange rods, fill all the holes around the edge of the spinning spool.
• Place the short side of a green trapezoid into the slit on the end of each of the orange rods. To start off with, make them all parallel to the spinning spool, i.e., flat side front.

4.  Set up the small fan a good distance away to start.

5. If you think it is necessary, weight the base of the tower to prevent it from being blown over.

6. Turn the fan on low and see if the windmill turns. If it does, use a watch or timer to determine the number of revolutions per minute and record this number.

Extend Your Understanding of Windmills

In this section, students extend their understanding of their observations by making alterations to their basic project.

1. See what happens to the windmill's revolutions per minute (rpm) when you do the following (first one at a time; then try some combinations):

• Change the location of the fan.
• Use fewer blades.
• Place the blades on yellow rods instead of orange rods.
• Place the blades on blue rods instead of orange rods.
• Change the orientation of the blades by tilting them.
• Change the material of the blades by substituting cutout blades of other materials.
• Change the shape of the blades, by cutting out larger, or pointed, or otherwise altered blades.
• Change the shape of the blades by curving them.
• Change the speed of the fan.
• If you have a Tinkertoyâ„¢ motor, attach it to the hub and use the electricity created by the windmill to do something (for example, cause a small lightbulb to light).
• Change the height of the fan so that it is blowing slightly up or slightly down at the windmill.
• Adjust the base so that the windmill can take higher speed winds.
• Take the windmill outside. Find the location around your home in which it functions best. Analyze the conditions to determine why.

2. Describe the optimal and the least optimal conditions for the operation of your windmill.

3. Visit a wind farm and observe particularly the blades and the location. Ask questions to gain a better understanding. Compare the conditions for optimal function of the turbines at the wind farm with those for your model windmill.

4. Research the history of windmills.