Lab # 2 – Crazy Coasters and the Exploration of Potential vs. Kinetic Energy

Introduction

The purpose of the coaster's initial ascent is to build up its potential energy. The concept of potential energy, often referred to as energy of position, is very simple: As the coaster gets higher in the air, gravity can pull it down a greater distance. You experience this phenomenon all the time: think about riding your bike or pulling your sled to the top of a big hill. The potential energy you build going up the hill can be released as kinetic energy -- the energy of motion that takes you down the hill.

  

Problem 

How does height affect the energy on an object?

Hypothesis   

I hypothesize that the higher…..

Materials

Foam pipe insulation

Glass marble

Ruler

Tape

Triple beam balance

  

Procedure

1. Construct your crazy coaster track using the materials provided.
2. Measure the length of track and record your data into your Results.
3. Lay the track on the ground and make a loop with 1/3 of the length; the loop should be ~ 26-30 cm in diameter.  Tape the loop to the side of the track to keep its shape.
4. Take turns trying to get the marble to complete the loop successfully; a marble that does not complete the loop or jumps the track is unsuccessful.  Record your data in the table below and make any additional observations on its energy. 
5. Using a balance, weigh the mass of the marble and enter it below.

Additional Data

Mass of marble = ___ grams

Length of track = ___ cm

Loop diameter = ___ cm

Results  

Starting height (m)	Successful loop completion by marble – 3 trials (Y/N)	Additional observations about the marble's "energy" – three sentences, one for each observation
0.25	1. 2. 3.	1. 2. 3.
0.50	1. 2. 3.	1. 2. 3.
0.75	1. 2. 3.	1. 2. 3.
1.00	1. 2. 3.	1. 2. 3.
1.25	1. 2. 3.	1. 2. 3.
1.50	1. 2. 3.	1. 2. 3.
1.75	1. 2. 3.	1. 2. 3.
2.00	1. 2. 3.	1. 2. 3.
2.25	1. 2. 3.	1. 2. 3.

Starting height minimum for successful loop = ____ cm

Starting height maximum for successful loop = ____ cm

Calculate the marble’s Potential Energy (P.E.), at each position, using the following equation:

Potential Energy = (mass)(gravity)(height)

P.E. = mgh

 (note: gravity ~ 10 m/s²)

  

  

Analysis

 1.       At what heights were you able to successfully complete the loop?

2. Why didn’t the marble complete the loop at lower positions?  At higher positions?

 How does height affect potential energy?

3.  Where on the crazy coaster was the marble’s potential energy its lowest?  Its highest?  Draw a picture and label these positions.

4a. Describe the energy the marble would have at a starting height of 0.0 m. 

4b. Calculate the PE of your marble at a starting height = 0.0 m.

Conclusion

What was your problem?

Restate your hypothesis.  Was your hypothesis right or wrong?  What facts would support this? What was the independent variable?  What was the dependent variable?  What is

What did you learn in this lab?

What did you like about this lab?

What were some challenges you had to deal with?

What could you do next with this problem?  What other tests could you perform?

Write down any other additional thoughts, observations, inferences, etc.