what is the center of a trampoline called
Trampoline The fabric that users bounce on (commonly known as the "bounce mat" or "trampoline bed") is not elastic itself; the elasticity is provided by the springs that connect it to the frame, which store potential energy.
History of the roller coaster In 1959, the Disneyland theme park introduced a new design breakthrough in roller coasters with the Matterhorn Bobsleds. This was the first roller coaster to use a tubular steel track. Unlike conventional wooden rails, which are generally formed using steel strips mounted on laminated wood, tubular steel can be bent in any direction, which allows designers to incorporate loops, corkscrews, and many other maneuvers into their designs. Most modern roller coasters are made of steel, although wooden roller coasters are still being built along with hybrids of steel and wood.