How could your machine convert one form of energy to another?įinally, you can use this project to demonstrate the engineering design process. Or, the energy could come from work that you do with your hand by exerting a force. It could come from gravitational potential energy, the energy stored in an object that is raised up off the ground. Where will that energy come from? It could come from elastic potential energy, the energy stored in a stretched material, like a rubber band. The ball needs kinetic energy, the energy of motion, in order to fly through the air. You can also use this project to learn about energy. How do the initial velocity (starting speed) and launch angle (angle at which an object leaves the launcher) of a projectile affect its range (distance it travels)? What trajectory (path through the air) will make it easier to catch the ball? A high, steep trajectory or a low, shallow trajectory? You can also use this project to learn about projectile motion. Think about how you could incorporate different aspects of these machines into your design. You can also investigate more complex machines, like catapults, trebuchets, or slingshots, that are used to launch projectiles. The bibliography has websites to jump-start your learning.įirst, this is a great opportunity to learn about simple machines, like the lever or the inclined plane. Choose one or two to learn about in more detail. If you are doing this project for a science fair, do not worry about learning about all of these topics. Rather than explaining each of these topics in detail, this background section will give you a brief overview of each one, and then you can do more research using the links in the bibliography. This challenge gives you the opportunity to explore some interesting topics in physics and engineering. Different designs for launching (left) and receiving devices (right).

Two receivers are made from paper, a plastic cup, tape and pencils pictured on the right.įigure 1. Two catapults are made from pencils, plastic cups, tape and a ruler and are pictured on the left of the image.

Catapult launcher