Maybe your parents have one at home that you can play with. You might notice that it's very springy. Look at the picture of the man jumping from the bridge. First, as I stepped off the bridge gravity pulled me down. Gravity is a force that always pulls us toward the ground.
Forces are things that push or pull.
Only gravity is pulling me down. Because gravity is the only force acting on me, I could say I'm in free-fall. When I'm in free-fall, gravity causes me to accelerate toward the ground. When the bungy cord is stretched out, a scientist would say it has energy. Energy is just the ability of a thing to do work like move a car or spring back into place or fall towards the ground.