Download Energy Conservation Lab

Name __________________________________
Block______ Date ____________
Conservation of Energy Lab
Goals:
- Test how much energy is converted into useless forms when a marble rolls in a
foam track, and during a pendulum’s swing.
- Practice measuring potential and kinetic energy.
- Build and analyze a sample roller coaster from the perspective of energy.
1. Conservation of PE
Using one half of one ‘tube’ should provide you with about 6 ft (~2m) of track.
With two ring stands make a U out of your track, so that the ends of your track are 60 cm
high, and the bottom of your track is touching the ground/table in the center. Start the
marble at the end of the track, release it, and record how high it comes on the other side.
Record this height, repeat 2 more times. Based on conservation of energy how high
should the marble have gone? What was the average initial potential energy for the side
you started on, and what was the average potential energy for the other side? What
happened to the rest of the energy? What does this tell you about the energy of the
system? How much PE would the marble have when it was at the bottom of the U? How
do we know?
2. Energy conversion
Set up a half U of track like you did at the beginning of pt. 1. Release the marble
from heights of 0.5 m and 1 m and record how much KE the marble has after it rolls onto
the floor right off the track. Record your data. How much kinetic energy did you
expect the marble to have? What does this tell you about the energy of the system?
3. Roller Coaster
A. For a starting height of 1.5 m, what is the largest diameter of a loop-the-loop
that you can consistently get the marble to go around from this starting height? Compare
this diameter (and this the height of the top of the loop) with your overall height. How
much kinetic energy should the marble have at the top of the loop? How much potential
energy? What velocity?
B. Build a roller coaster with the tube, include humps, loops, & twirls if you can.
4. Pendulum
Construct a pendulum with a bob which has a mass of 50-200 g. The pendulum
should be 45 cm long. Pull the pendulum back 20 cm from its neutral position. Let it
swing at least 5 times. Record the time it takes for one swing (period). Where does the
bob have the most KE? Most PE? Measure how much PE you think the bob should have
at its starting point, record this number. How much KE should the bob have when its PE
= 0? Sketch graphs for PE vs. time and KE vs. time (2 graphs).