One of the easiest ways to cool off on a hot summer's day is with an electric fan. You could buy a fan from any department store or you can build your own using a few simple tools and household objects while learning about how they work in the process.
Loop a length of magnet wire around a tube of toilet paper or shot glass five to 10 times. Allow about four inches of room on both sides of the loop. Wrap the ends of the wire around the loop to hold it together.
Strip the enamel from one end of the wire using fine-grit sandpaper. Leave about 1/4 inch where the wire joins the loop. Do the same for the other end, but only strip the enamel off of one half of the wire.
Bend two paperclips into a "W" shape and attach them to the terminals of the battery using a large rubber bands, so they can "cradle" the loop assembly.
Join the battery and a strong magnet with the other rubber band so the magnet faces in the same direction as the cradle.The polarity of the magnet is unimportant.
Test the motor by placing the loop assembly into the cradle. If it works, it should spin. You may need to start the motor by hand with a gentle flick.
Build a set of fan blades by taking four business cards or credit cards and gluing them together in an 'X' shape.
Attach the fan blades to to the motor's loop by poking the wire through the cards and securing it with a drop of glue. If you used old credit cards, you might need to use a hot needle to help start the hole.