O I NTHE SCREAM MACHINE T C U D O R T N I It’s finally your turn You step into a roller coaster car and safety bars lock you in your seat You hear the click click click click as a machine pulls the cars up the first huge hill Up at the very top you see the steep drop ahead of you Ready Hang on tight 4
The cars speed down the hill It makes your stomach feel a little woozy as though it’s floating inside you You let out a loud scream The roller coaster cars hurtle along the track They have enough momentum to move around it by themselves No engines do the work The cars fly around curves and even go upside down on loops This is energy at work The cars gather potential or stored energy as they are lifted to the top of the first hill When the cars travel down the hill that stored energy changes to kinetic energy the energy of movement
WHAT IS ENERGY Energy is the ability to do work such as moving around a roller coaster track There are many types of energy Electrical potential and kinetic energy are three forms Motion is essential to energy It can spark the change from one form to another On most roller coasters a machine uses electrical energy to pull cars up the first hill That energy becomes potential energy and then kinetic energy as the cars fly down the hill Energy constantly changes but is never destroyed So when one form of energy becomes another the amount of energy is always the same Forces play a role in this transformation The machine that pulls roller coaster cars up their first hill is an electric winch 1 R E T P A H C 6
MEASURE IT MEASURING ENERGY 216,000 J Playing soccer for 6 minutes 450,000 J A car traveling at a speed of 60 miles per hour 97 kmh 1 MILLION J A roller coaster s stored energy at the top of a 164-foot 50 m hill Work equals the amount of force used times the distance an object is moved The unit used to describe this work is a joule J This chart shows how many joules it takes to do different kinds of work 7
