An anemometer measures wind speed. A homemade anemometer will not measure wind speed in mph, but in revolutions per minute. The homemade anemometer is made of paper cups, strips of cardboard, a push pin, a pencil and modeling clay. Other required materials include a colored marker, staples and ruler. Wind speed is determined by counting the number of revolutions the cup makes in one minute.
Arches are used in many forms of architecture including bridges and igloos. This project requires four eggs, tape and books. The eggshells are emptied and formed into domes. The domes are placed in a rectangle and books are placed on top. Even though eggshells are fragile, the dome shape of the shells provides strength and the shells will hold a surprising amount of weight.
Water is often filtered using sand and gravel to remove impurities. A water filter can be created from a 2-liter soda bottle, gravel, sand, cotton balls and dirty water. Cut the soda bottle in half and place the top half inside the bottom half like a funnel. Kids can then layer the filter materials in the funnel part to create a filter. The kids can experiment with layering the items in a different order to see which works best and take the filter apart to see what types of contaminants were removed by which substance.
A hovercraft works because it rides on a cushion of air, which reduces the friction between the bottom of the craft and the floor. A simple hovercraft is made up of a paper plate, film canister, poster putty and a balloon. The paper plate forms the bottom of the hovercraft, the film canister directs the air and the balloon provides the force that lifts the craft. The paper plate and film canister have holes punched in them to focus the stream of air.