PhysicsLAB Lab
Marble Tube Launcher

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In this lab we are once again going to take distance measurements and analyze our results using graphical analysis.
You will need the following equipment:
  • one launch tube
  • one stand with test-tube clamp
  • tape
  • one plumb line
  • three sheets of printer paper (target paper)
  • three sheets of carbon paper
  • two meter sticks
  • one marble
Set up the first three pieces of equipment as shown in the following picture making sure that the top of the tube is at least 25 cm above the top of the table.
Next use a plumb line to place your target paper on the floor. The plumb line allows you to locate the edge of the table on the paper so that you can measure the horizontal distance each marble travels when it rolls off the table. Draw a line on your paper to mark its location.
Now tape your target paper to the floor so that it won't move. Place the carbon paper on top of it to record the positions of the marble's strikes.
To collect data, you will release the marble from 10 different positions/heights along the tube. Do not adjust the clamp or the stand, just place the marble along the tube and measure the height of the side of the tube - you should be able to get 10 positions by decreasing the height by 2 cm with each trial. You will deal with the thickness of the tube later.
When the marble leaves the table it will fall through the air and strike the carbon paper on top of your target paper. Mark each impact as it occurs, making sure that you know which impact position correlates with each release position. Release the marble twice from each height to insure that your experiment has consistency. Do not worry if the impact points are slightly different - if in doubt, run a third trial.
Make sure that you replace the carbon paper after you mark each impact before releasing the marble from the next height.
When all ten heights have been completed, you may carefully remove your target paper off the floor. Make sure to place all group members' names on the paper, as well as your period.
Refer to the following information for the next ten questions.

Carefully measure the distance of each impact position from your plumb line to the nearest millimeter since our tube measurements were only taken to the nearest 1/10th of a centimeter.


impact #1

impact #2
(cm) (cm) (cm) (cm)
Now measure with a meter stick the height of your lab table, including the thickness of the tubing. Record your answer in centimeters. 

Refer to the following information for the next seven questions.

Graphical Analysis
After completing your data table, you need to go to the file system and open the EXCEL workbook entitled 1-tube. Immediately resave the file with the title to tube_LastnameLastname.xls in your period folder.
On the first worksheet, you will be graphing Release Height vs Average Impact Distance. EXCEL will allow you to quickly adjust all of your height measurements for the thickness of the tube. Measure your tube's thickness (to one decimal place) and place its numerical value in cell B2 (it is the green cell). 
Next place your original measurements in columns B and C. EXCEL has been programmed to subtract your tube thickness and plot your data.
What is the name of your file?

What is the coefficient of restitution, R2

As the release position decreased, which of the following is true of the impact distance?
In this lab, which of the following was the independent variable?
What shape is your graph?
What was the value of your graph's exponent for x? 

Explain what an exponent that is less than "1" means.

Refer to the following information for the next three questions.

Data Analysis
Worksheet #2 will convert your graph from worksheet #1 in to a line by having you square your values for the average impact distance. Understanding the physics behind this result is not a requirement: it involves knowledge of conversation of energy, moment of inertia (the ball's rotation), and horizontally released projectile motion.
What is the slope of your line? 

What is the unit on the slope of your line? 

In this experiment what previous meaurement does the slope represent? 

When you lab has been completed, you are to turn in your target paper as well as your data sheets. Also, make sure that all of your information has been submitted online.

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Catharine H. Colwell
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