Windmills serve many purposes. They create energy that, with some engineering, can create electricity for a small town, pump water through a dam or irrigation system or simply turn gears to grind corn and other grains. Windmills have a long history starting on farms and continuing through present day with wind turbines. Children can learn about the different uses for windmills and make one of their own as a follow up activity. Since this windmill really turns, children get a look at how a larger windmill might work.
Draw an isosceles triangle on your cardboard, using your ruler to make sure the edges are straight. Start with the base, making it 6 inches wide. Draw a second line projecting up from the centre of your baseline about 8 inches. Connect the centre line to the ends of the base line to create your triangle.
Place your ruler across your triangle about 4 inches from the tip. Draw a horizontal line and erase the point of your triangle so the shape has a flat top. Cut out your new figure and use it as a template to create three more figures.
Tape your figures together at the edges. This is the base for your windmill. Paint it white or light brown and paint on more details like a door, windows and vines growing up one side. Cut a square from your scrap cardboard, tape it to the top of your windmill to close it and paint it to match the rest of the model.
Cut a 5-inch square of cardstock and draw a line in from each corner to the centre so that your square has an X on it. Cut along this X, leaving the centre of the square intact. Bend the tip of the top flap of each cut to the centre of the square and secure them there with a push pin, creating four wind sails.
Cut the points from your wind sails so they look more like real windmill sails. Push the push pin holding your sails through the front of your cardboard model. Snip the eraser from a pencil and use it to cap the pin's tip on the inside of the windmill.