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

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

Introduction

Who likes roller coasters?  I do! 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 the starting height of a marble on a coaster track affect the speed it gathers to complete a successful loop?

Hypothesis

I hypothesize that if... _________________________________________________________________________________ then... __________________________________________________________________________________________________ because... __________________________________________

Materials

Foam pipe insulation

Glass marble

Ruler

Tape

Triple beam balance

Procedure

1. Construct your crazy coaster track using the materials provided.
2. Lay the track on the ground and make a loop with 1/3 of the length; the loop should be ~ 24-30 cm in diameter.  Tape the loop to the side of the track to keep its shape.
3. 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. 
4. Using a triple beam balance, weigh the mass of the marble and enter it below.
5. Measure the length of track and record your data into your Results.

Variables:

Independent
Dependent
Constants

  

Additional Data

Loop diameter   = ___ cm 

Mass of marble = ___ grams

Results

Starting height (cm)	Successful loop completion by marble – 3 trials (Y/N)	Additional observations about the marble's "energy" – one prediction, one observation, one inference for each starting height.
0.0 cm	1. 2. 3.	Prediction: Observation: Inference:
25.0 cm	1. 2. 3.	P: O: I:
50.0 cm	1. 2. 3.	P: O: I:
75.0 cm	1. 2. 3.	P: O: I:
100.0 cm	1. 2. 3.	P: O: I:
125.0 cm	1. 2. 3.	P: O: I:
150.0 cm	1. 2. 3.	P: O: I:
MAX ___ cm	1. 2. 3.	P: O: I:

Variables:

Independent
Dependent
Constants (3)

Estimate the marble's Kinetic Energy by eyeballing its speed (3 is fastest and 1 is slowest)

Point A
Point B
Point C

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?

3.        How does height affect potential energy?

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

5.       Starting height minimum for successful loop = ____ cm

6. 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) 

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

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

7. The Law of Conservation of Energy states that energy is never created or destroyed; it just changes form.  How do your results show this?

8. Bar graph showing how starting height affects the energy of a marble completing a loop.  
Graph your data.  
X- axis: Starting Height (cm) Potential Energy;
 Y- axis: Successful Loop - Yes, No,  Kinetic Energy 

Conclusion

What was your problem?

Restate your hypothesis.  Was your hypothesis right or wrong?  What facts would support this?

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.

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Table of Contents	Page numbers, title of lab, dates all present	One is missing	Two are missing	Two missing & incomplete	Three missing	ZERO
Title of Lab	Written with full heading at beginning of lab	Written in wrong location	Partially written	----	---	ZERO
Problem	Copied from Science Scholars Blog	Partially written	---	----	---	ZERO
Hypothesis	Written after Problem, If... Then... Because... statement present	If... Then... Because... statement present, but wrong location	Partially written	----	---	ZERO
Materials	Copied from Science Scholars Blog	Partially written	---	----	---	ZERO
Data Tables	Ruler used, data entered, units shown, numbers rounded to nearest tenth	One aspect missing	Two aspects missing	Three aspects missing	Incomplete	ZERO
Graph	Title present, x and y axes labeled, units listed matches data from tables	One aspect missing	Two aspects missing	Three aspects missing	Incomplete	ZERO
Analysis Q/A	ALL of the questions are answered	One aspect missing	Two aspects missing	Three aspects missing	Incomplete	ZERO
Conclusion	ALL of the questions are answered	One aspect missing	Two aspects missing	Three aspects missing	Incomplete	ZERO
Additional observations, sketches, inferences	Evidence shown	---	---	----	---	ZERO