On a family trip to New Mexico this summer, we saw a wind farm. My boys were curious how the windmills worked. I told them that the wind made the windmill turn, and the windmill was attached to a generator that turned the movement into electricity. They were ok with that explanation, but I thought a hands-on activity would help them better understand. So I found a model windmill kit as a fun STEM activity for us learn about wind energy!
Wind Energy STEM Activity: Building your own model Windmill
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I found this windmill model kit, which looked simple enough for us to build together.

Building a Windmill
First we took everything out of the box, and made sure we had all of parts. To confirm we had what we needed, we matched each piece to the bill of materials provided with the instructions. When I looked at the instructions, the first thing I noticed was that an exploded view of the windmill was provided. I showed it to my son, and reminded him we had learned about exploded views with another toy.
What a love about exploded views is you can see exactly how something is put together, even without instructions. Or, if something in the instructions is unclear, the exploded drawing always clears it up.
Our Windmill’s Gear Train
The first step was to connect a large gear to a small gear. The small gear connects to a generator, and the large gear connects to the windmill. The two gears make up the windmill’s gear train. A gear train is a series of gears that transfers motion from the beginning to the end of the train. The windmill’s gear train transfers motion from the windmill to the generator.
Depending on the sizes of the gears, motion is either sped up, slowed down, or kept the same. The windmill’s gear train, when the large gear completes a full rotation, the small gear turns 6 times. So motion in the gear train speeds up.
What is a generator?
The generator changes the mechanical motion of the windmill into electricity. In other words, it converts the kinetic energy from the rotating windmill into electrical energy.
Turning Wind Energy into Light!
The next step was to connect the wires from a small light bulb to the generator. We learned from one of my son’s Tinker Crates that electrical energy (or electricity) is created by the flow of electrons. Connecting the light bulb’s wires to the generator allows electrons to flow from the generator to the light bulb. So now when the windmill spins, the light bulb turns on!
Putting our Windmill Together
We connected the windmill blades to the shaft of the large gear. The final step was to attached the windmill assembly to a stable base. We filled an empty water bottle halfway with sand, then screwed the windmill onto the water bottle.
Now it was time to test out our windmill! We took it outside on a windy day, and lo and behold, our windmill worked. We were able to use wind energy to power the light bulb!
Did you enjoy this STEM activity? Try some of my other ones!
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