Vinegar

• Measure how high your egg can bounce when it doesn't have a shell that can crack. For this experiment, you can use vinegar, which is an acid, to dissolve the egg's tough exterior. First boil an egg in water. Place the egg in a jar of vinegar and let it sit for a few days. Within about four days, the egg shell should have completely dissolved. Remove the egg from the jar with a spoon and pat it dry. Drop the egg from a few inches in the air and watch it bounce. Record this process for your science fair project.
  
  

Sizes

• See if the size of eggs makes a difference in their bouncing abilities. Buy a variety of chicken eggs, including small, medium and large ones. Boil each egg and place them in vinegar to dissolve the shell. Set up a measuring tape along a wall where you can measure how high each egg bounces. When the eggs' shells have been removed, bounce each egg from a certain height, around two inches above the ground. Continue increasing the height they're dropped from until only one egg is left intact. Record and analyze your data to understand why a certain size egg faired better than the others.
  
  

Padding

• If you don't have enough time to let an egg shell dissolve in vinegar, experiment with ways to make a shelled boiled egg bounce. Wrap various materials around the egg to find out what will not only help it bounce off the ground, but also keep the shell intact when it hits the floor. Bubble wrap, socks, foam, rubber bands and tissue paper are just some of the materials you can secure around the boiled egg and experiment with for this science fair project.
  
  

Materials

• Find out what kind of floor materials will best support a boiled egg and help it bounce. Select an array of materials that you think will be both soft for the egg and bouncy, including pillows, foam, blankets, cellophane and rubber. Hold these materials taut with a measuring tape nearby to see how high the eggs bounce on each one. Record and analyze your data after the experiment to understand why one material might be more bouncy and supportive than the others.