Why don't you fall out of a roller coaster when it goes upside down? Which is stronger, your arms or your legs? Why do skydivers spread out their bodies when they jump from a plane? All of these questions can be answered by studying the properties of force and motion. These hands-on experiments are easy to carry out and most require simple items that can be found in the home or at school. For those wishing to enter a science fair competition, every...