Catapults are machines that fascinate kids and adults, and teaching kids about them should be fun and exciting. Because several types of catapults exist -- the trebuchet, the mangonel, the onager and ballista, to name a few -- you'll want to keep your explanations of the physics simple and brief. Focus predominantly on keeping your students engaged with the subject of catapults and why they're so interesting

Start with a Demonstration

One of the biggest mistakes you can make is to begin a potentially riveting lesson by giving students all the information and history first, in an attempt to "get it out of the way." Instead of boring the students, start with a demonstration of a catapult at work. Bring a small, tabletop catapult into the classroom and show the kids how it works. Perhaps even supervise a few students while you allow them to use it.

Tell a Story

Once the kids are engaged by the demonstration, use this opportunity to teach them about the history of catapults. This is also when you can briefly explain the types of catapults and how they were used. Remember to refer to the tabletop catapult whenever possible to keep the kids engaged with the actual object. As for the history lesson, always try to give the information in the form of a story. If possible, choose a specific incident to illustrate each of your points.

Modern Uses

Make sure to teach the kids that catapults are not simply ancient machines, but ones that are still used today. Most catapults today are used by the military: aircraft carriers use catapults to fling airplanes into the sky. Previously, they had been used in the trenches during World War I as a method of launching hand grenades at the enemy. Today, catapults also find their ways into the hands of children, as slingshots

Build a Catapult

Leading kids through a craft project will cap the lesson magnificently. Each student will need an empty soup can, a Popsicle stick, a few rubber bands, a small rectangle of cardboard and some tape. Instruct each student to wrap the rubber bands around the top half of the can, then insert the bottom part of the stick underneath the belt of rubber bands. Then have the kids tape the cardboard to the top part of the stick, on the side that faces away from the can. They can then fold small flaps into the cardboard so that it better holds the payload. Open a bag of plain popcorn and let the kids fire away,