Show students the materials.
Give them their challenge:
Make a device that turns in the wind. For older students add that it could be used for measuring how fast the wind is going.
They can test their device by blowing on it, or ideally, by taking it into/making it in the wind outside.
After students have worked a while, state the key design components:
(to help students that are still to start on a design, and to conceptually frame designs already in progress)
A pivot: parts that can spin around each other.
"Blades" that can catch the wind: larger surface areas that the wind can hit and push against.
It might be useful for them to refer back to these if they get stuck in their designing.
Show younger or less mechanically minded students different ideas for making a pivot (there are many other ways):
1. a skewer in an inverted tube/pen cap (to which the blades can be attached)
2. a skewer through a straw (to which the blades can be attached)
There are other ways to make a pivot, but these are the simplest.
For Kindergarten students, provide them with tube-and-skewer pivot, cardboard, scissors and tape. Demonstrate how the tube spins on the skewer. Draw and name shapes that they could cut out of cardboard ("rectangle", "triangle", "blade shape" good to include), to tape to the tube. They can add more shapes if they want. Depending on how they tape the blades onto the tube, and so how floppy the blades are, they may need to be shown how to strap a strip of curved cardboard across two blades to hold them steady.
Allow students time to freely experiment, discuss ideas together (and "steal" good ideas from each other, as all good designers and architects do).
The Play-Debrief-Replay method for teaching works well for this activity - see notes in the resource.
If students are in need of help, either ask them to visit other wind machines that are spinning in the classroom, or help them focus on some ideas (e.g. see pivot ideas above).
Once they are done experimenting, review the different ways of making the key machine elements (pivot; blades to catch the wind)
During discussion, refer to uses of wind machines:
Anemometers measure wind speed - cups that spin around a shaft. Using magnets, the number of turns is translated into wind speed. (Show real anemometer if possible.)
Other applications of machines that turn in the wind:
(Wind vanes have a blade that turns in the wind, but its position stablilizes to show the direction that the wind is coming from.)
Windmills are wind machines used to pump water for farming or for groundwater extraction. They were also commonly used for grinding grain. They are complex machines of levers, wheels and gears.
A wind turbine is a windmill used to generate electricity: the energy in wind turns a blade which runs a generator to make electricity. Wind turbines are in greater use with increasing sustainable energy practices.