Physics 8
Name ________________________________
Chapter 11 Lab
Start Date ________________ Period ______
Due Date _________________
Speed of Marble – Two Positions
Introduction: This activity is designed to help with equation skills, graph development, graph
interpretation, and applying learned information to future situations.
You will be rolling a marble down an inclined plane (ramp). While the marble is rolling, you will measure
and record time (seconds) at the 50 cm mark and at the 100 cm mark. Speed can then be calculated
because you know distance and time for each position.
Equation:
v= (df – di) / (tf – ti)
v = d/t
Equipment:  one textbook
 marble
Question:
v
df
di
ti
tf
= speed or velocity
= distance final position : (50cm or 100cm for this lab)
= distance initial : (0cm for this lab)
= time initial : (0 seconds for this lab)
= time final position
 stopwatch timer  pencil or pen
 inclined plane (with length marked)
How will the speed of the marble at the 50cm mark
compare to the speed at the 100cm mark?
Hypothesis:
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Set-up Diagram:
marble
50 cm mark
100 cm mark
ONEText book
Inclined Plane
Physics 11.2 Marble Lab 10.2014
calculator to keep the
inclined plane straight
stopwatch timer
Procedure:
1.  Locate a table, clear of obstructions (binders, purses, water bottles, etc.)
2.  Review safety procedures with today’s materials.
3.  Gather materials.
4.  Setup the textbook and inclined plane as shown in the setup diagram.
5.  Locate the 50cm mark on the inclined plane. Place a pen or pencil on the table at the 50cm
mark so as the marble rolls, you can see when to stop the timer.
6.  Place the marble at the top of the inclined plane at zero distance (0cm).
Data Gathering:
7.  Find the time necessary for the marble to roll from 0cm to the 50cm mark [to the nearest
1/100ths of a second (.01)]. Record the time as Trial #1 on the data table titled “Marble Rolling
Data Table.”
8.  Repeat steps 6 and 7 for two other trials for a total of three trials at the 50cm mark.
9.  Repeat steps 6 and 7 for a total of three trials for time at the 100cm mark.
10.  Calculate the average of the three trials for the 50cm mark and the 100cm mark to the nearest
0.01 second. Show the 2 “average time” ESA’s below. Record on the “Marble Rolling Data
Table.”
Plot these two columns
Marble Roll Data Table
Final Distance (df)
From Start (cm)
Time Trial #1 (s)
Time Trial #2 (s)
Time Trial #3 (s)
tf Average Time
(s)
Speed (cm/s)
0
0
0
0
0
0
50
100
Workspace to calculate average time:
average time = Trial #1+ Trial #2+ Trial #3
3
Physics 11.2 Marble Lab 10.2014
Equation Skills:
11.  Calculate the speed of the marble at the 50cm mark and 100cm mark to the nearest 0.01
second. Write the ESA’s for each distance on the “Speed Calculations Table.” Be sure to have
units for EVERY number! (Ex. 2.10 sec)
di = 0.00 cm
tf = average time
Speed Calculations Table
Equation
Substitution (units)
Answer (units)
Speed at the
50cm mark
Speed at the
100cm mark
12.  Place the speed values for the 50cm mark and 100 cm mark into the “Marble Roll Data Table.”
Graph Development:
13.  The horizontal axis is called the “x” axis or the independent axis. Design the axis numbers
so the maximum value is near the end of the axis. Example, if the maximum time is 3.14s, the
value 3.14 should be near the end of the axis. Plot time in seconds on the horizontal axis for the
average time at the 0cm, 50cm, and 100cm values.
14.  The vertical axis is called the “y” axis or the dependent axis. Design the axis so the
maximum value is near the end of the axis. Plot distance in centimeters on the vertical axis for the
0cm, 50cm, and 100cm values.
15.  Connect the three points with a curved line. This line represents the graphical relationship of
distance with time, for the rolling marble. In other words, the slope of the line represents speed of
the marble.
16.  Notice the curved line representing speed of the marble with time.
17.  Return all materials to the appropriate area.
Conclusion Questions: These questions will help you to see, interpret, and draw conclusions from your data measurements.
1. Was your hypothesis correct? Explain by using your speed ESA’s.
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Graph Interpretation:
2. Plot these values on the “Time-Distance Graph:” Connect the points with a straight line.
 (0s, 0cm),  (1s, 25cm),  (3s, 75cm. Label line “Steady Speed of 25cm/s.”
3. Describe how your “Time-Distance Graph” displayed the change in speed of the marble, as the
marble rolled the 100cm.
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Title: Distance – Time Graph