Paper windmills are easy to make and can provide a distraction for children on a rainy day. They also demonstrate the principles that make real windmills work, and help children learn how wind provides power different purposes. Paper windmills will turn in the wind by themselves, or by blowing on them. Making one takes just a few minutes, and if you have childproof safety scissors, the children can do it all themselves.
Fold a square piece of paper diagonally to make a triangle. Then unfold it and fold it again along the opposite corners. When you're done, you should have a pair of folds making an "X" through the paper. Paper size can vary greatly, but 8 1/2 inches on each side makes a good starting point. You can make paper squares that size by cutting the bottom 2 1/2 inches off of a standard piece of printing paper.
Measure 1 inch from the centre of the "x" along each of the crease marks, and use a pencil or marker to note those locations. You may need to measure a larger or smaller length, depending on the size of your paper, but 1 inch is a basic starting figure.
Cut a straight line down each crease with a pair of scissors until you reach the points you have marked. Don't cut past those points; otherwise, the paper will fall into pieces.
Grasp one half of the corner you have just cut and pull it down to the centre of the "X." Be careful not to crease it or fold it. Repeat this process with all four corners until they are all in the centre. Use the same side of each cut every time: if you pulled down the corner to the left of the first cut, pull down the left-hand corners of the remaining three cuts as well.
Stick a pin firmly through the centre of the paper, making sure it pokes through all four folded corners, as well as the back of the paper. The paper should now form a windmill-like pinwheel.
Stick the pin with the pinwheel attached through an unsharpened pencil or a tall, thin stick. If you use a stick, secure the pin to it with a bit of white glue. If you use a pencil, stick the pin through the eraser: the rubber should hold it firmly in place.
Move the windmill gently from side to side, blow on it, or hold it up to a light breeze to watch it spin.
If you like, decorate the pinwheel by sticking bits of ribbon into the tips when it is complete. Alternately, colour the paper using crayons or markers: multicoloured paper will make the windmill more spectacular.