A very fun activity to do on a sunny day is jump on a trampoline. Fun for all ages, a trampoline makes it easy to get major air. What exactly is behind this mechanism of a trampoline flinging a person into the air? Well let's talk physics in terms of energy.
Let's say that our reference level is where one stands on the trampoline. As soon as a person stands on a trampoline the webbing is stretched and sinks down to equilibrium. This is similar to our lab experiment of placing a mass on a vertical hanging spring. Now once a person stretches below equilibrium (by pressing down a force and/or jumping up) the fun begins. A person has a potential energy at the top of their jump, and this is converted into kinetic energy as they move, which is then turned into spring potential energy, when a person stretches below equilibrium level.
This idealogy is the basic physical concept of a trampoline. With this knowledge a person can incorporate cool and crazy tricks to do on a trampoline.