Here’s a fun activity that will introduce your fourth grader to the concept of frictionless motion by constructing a hovercraft. A hovercraft is a vehicle that travels on a layer of compressed air just above any kind of land or water surface. The compressed air serves as an invisible cushion that eliminates almost all friction between the vehicle and the surfaces.
What You Do:
- Cut a 4-inch square out of the cardboard.
- Punch a hole in the center of the cardboard. The hole should be the same size as the hole in the spool. If using a spool with yarn or string wrapped around it remove the string.
- Glue the spool to the cardboard on top of the hole. Make sure the holes line up. Use enough glue to assure that no air can escape between the spool and the piece of cardboard.
- Cover the top of the spool with a circle of paper. Glue it to the spool and allow to dry.
- Punch a hole in the middle of the paper cover where the hole of the spool is. Now your hole should run through the paper, spool, and cardboard without any obstructions.
- Inflate the balloon and pinch the end to keep the air from escaping. Stretch the balloon over the top of the spool.
- Set the hovercraft on a level surface (table top, floor, etc) and let go of the balloon. Give the hovercraft a few gently pushes.
The air flowing from the balloon through the holes forms an air cushion between the craft and the flat surface, which reduces the force of friction (the resistance that occurs when two object rub against each other). With little friction to slow it down the hovercraft shoots across the table!
Mike is a 20-year veteran science teacher, and runs an online business (www.scienceinabag.com). Over the years Mike has studied trends in science, education, and finance, conducting research, developing programs, and writing articles on these topics.