My PBL Project-Roller Coaster

Introduction

This project demonstrates the scientific principle of conservation of energy. All of the potential energy the roller coaster has at the top of the hill is the close to the same (because of friction) amount of potential energy at the end of the track at the same or close to the same height. The water and the cup remain on the cart because of inertia.

Driving Questions:

Why do both of the cars finish at the same time, even though their tracks are different? Why does the water stay in the cup when the cart goes in the loop-the-loop?

Materials

• Pasco Roller Coaster Kit

• Scissors

Procedure

• 1. Assemble the roller coaster.

     1. Place the inserts and washers into the holes.

     2. Place the blue pins inside the inserts in the shape of the ramp and the loop.

     3. Put the clips in along the underside of the track.

     4. Adjust the clips and clip the track onto the blue pins.

     5. Clip the track onto the pins.

     6. Cut off the excess track, but leave a small amount excess.

     7. Slide the stops onto the end of each track making sure that they are next to each other and at the same height.

  2. Adjust the track so that the carts do not get derailed and so that both the carts get to the end at the same time.

Scientific Principle

This roller coaster set up demonstrates the scientific principle of conservation of mechanical energy. Since both carts start at the same height they have the same gravitational potential energy. Since they end at the same height, they have the same gravitational potential energy at the end of the track. The reason that the cup remains on the cart even in the loop-the-loop is because inertia keeps the water moving away from the center of the loop and into the cup and the cart. This inertia is often misinterpreted as centrifugal force, which does not exist. What keeps the cart in its circular path is centripetal force which is exerted by the track.