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Build a milk carton windmill

Windmills have been used since the first century. The first windmill was designed by a man known as Hero of Alexandria. I guess if your name is Hero, you better do something important! Windmills used to be used to grind grain and draw water. Now their descendants, wind turbines, are used to generate electricity for cities around the world. Approximately 4% of electricity in the United States comes from wind power.

How do they work?

When wind turns the blades of a wind turbine it turns a shaft inside the turbine. The shaft drives an electrical generator which generates the electricity. This can then be used by homes and businesses.

Okay, lets build one!

Here is an easy way to make a windmill that works really well. We won’t be generating electricity, but this model will still help show how the power of the wind can be harnessed. It can be built by using only a few materials, most of which you probably already have at home. It is also really quick to build.

Here’s what you’ll need:

  • Milk carton
  • Craft sticks
  • Card stock or cereal box
  • Wooden dowel
  • Hot glue gun

Building the windmill

First make a hole near the top of the carton. We did this by first poking a small hole with a screwdriver and then gradually making it larger. You want the hole to be very slightly larger than the thickness of the dowel. Once you have created the hole on one side, measure it and then make a hole in the same spot on the opposite side of the carton.

Building the windmill

Push the dowel through both holes in the carton. You can now widen the holes a bit. You want the dowel to be able to spin freely without a lot of friction.

Next glue two craft sticks together so that they form an”X”. Glue this X shape to the end of the dowel. We will use this to attach our windmill blades.

Cut four windmill blades out of card stock or a cereal box. You can make the blades any size you want provided they aren’t too tall to swing without touching the ground. Larger blades should catch more wind and be more effective. We cut ours approximately 1.5 inches wide and as long as we could. You can also make a small bend along the length of the blade so it catches more wind. Glue your blades onto the X shape attached to the end of the dowel and your done!

Building the windmill

One additional think we did with our windmill was to add a small bead of glue to the dowel on either side of the carton, leaving just enough space for the dowel to still spin freely. This helps the shaft to not slide in and out of the carton.

Test it out

Where we live there is no shortage of wind so we brought our windmill out onto the deck for testing. It immediately started spinning surprisingly fast. It definitely was a good demonstration of the power you can harness from the wind. You can also experiment indoors if you have a fan. A variable speed fan can help show the difference in how fast the blades spin depending on the intensity of the wind.

We were pretty surprised at how well this windmill worked from such an easy and simple build. Our next step is to attach something to the shaft of the windmill so that it can actually power something, but that is a project for another day.Testing the windmill

Testing the windmill

Build a milk carton windmill

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