Winding a Windmill

Challenge
The windiest month of the year is usually March. The second? April. It’s a little nicer in April than in March to fly kites, which is why it’s the National Kite Month. Besides flying kites, what else does the wind help us do? One thing that has become more common is using the wind to generate power (energy) with windmills. Windmills will be involved in the challenge this month. The challenge is to build windmill blades that generate the most power. How many blades should there be? What types of blades catch the most wind? Use your skills to find out!

Your windmill blades do have some criteria and constraints. Only the materials provided can be used in your design. The blades can only be a certain height determined by the height of the windmill base. The blade spokes need to be coffee stirrers or craft sticks, but part of the blade that catches the wind can be any material.

Materials

• index cards
• tissue paper
• toothpicks
• tape
• string
• foam ball
• wooden skewer
• empty juice carton
• small paper cups
• craft sticks
• coffee stirrers
• paper
• aluminum foil
• wax paper
• small 3 speed fan
• washers, coins, marbles, or other small objects for weights

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Hints and Tips for Success

1. Allow students planning and discussion time by having them experiment with the items to see how flexible and movable they are. They could also research different windmills to study the blades, how they are positioned, how many there are, or how they are angled.
2. After experimenting, allow student groups to plan their final design and decide which materials would be best. Include as many ways to improve their windmill blades as needed.
3. For differentiation, adjust the amount of materials available and allowed to use, add any additional materials, provide examples of blades that work, show them the different angles, start with little weight in the cup. Adjustments could be made to make it more challenging or simpler.
4. To make the windmill, fill the empty juice carton with heavy items to hold it in place. Poke the wooden skewer through the top of the juice carton and wiggle it around so the hole is big enough for the skewer to twist freely. Secure a piece of string the length of the carton to a small cup using tape or another fashion. On the dull end of the skewer, tie the other end of the string holding the cup. The students should be able to add weights to the cup. When the skewer twists, it should now cause the string to wrap around the end, raising the cup.
5. Give groups of students a foam ball to use as their center. This ball will be attached to the front of the windmill base, opposite the string and cup. Demonstrate how the windmill works with the students by attaching the foam ball and twisting it. Remind them that their goal is to cause the windmill to generate power by lifting the cup with weights. The fan should be placed in front of the windmill about 1 foot away.
6. Challenge the students further by using different speeds on the fan and adding more weight to the cup if they succeed.
7. Connect to science by discussing weather conditions including severe weather, speed of an object to the energy of the object, or energy and natural resources.
8. Connect to ELA by reading The Boy Who Harnessed the Wind by William Kamkwamba and Bryan Wheeler, where the main character builds a windmill to help provide a water well for the village. Nonfiction books about wind or windmills would fit well with this concept as well.