Introductory Experiment: The Experimental Procedure

The Experimental Question:
What variables affect the period of a pendulum?


In this experiment, you will measure the period of a homegrown pendulum. You will vary the parameters of the pendulum. You will change the length of rope and the mass at the end of the rope. Your objective is to discover which variables affect the motion of a pendulum.

There are three parts to the introductory experiment. The following describes the Experimental Procedure and materials you will need for this experiment. After you have gathered your materials and you are ready to perform the experiment, go to the Data Acquisition and Analysis section where you will learn how to record your data in the final part to this section, the Lab Notebook, where you can enter your data, refer to the generated graph, and answer the questions for analysis.

MATERIALS:
String
Washers (or weights)
Pencil
Yardstick (or ruler)
Stopwatch (Javascript stopwatch provided)

PROCEDURE:

  1. Make a pendulum by tying a washer onto one end of a piece of string, then measure 48 inches of string and tie a paper clip onto the other end.
  2. Hang the end with the paper clip from a high place.
  3. Release the pendulum.
  4. Use a stopwatch (there is one available in the the Lab Notebook) to time the number of swings in 30 seconds.
  5. Record the number of swings.
  6. Repeat several times using 1, 2, and 3 washers.
  7. Change the length of the string to 24 inches and repeat steps 4 ,5 and 6.
  8. Change the length of the string to 12 inches and repeat steps 4 ,5 and 6.
  9. Change the length of the string to 6 inches and repeat steps 4 ,5 and 6.
  10. Vary the starting angle (amplitude) of the swing to see if it affects the time each swing takes.

Now go on to Data Acquisition and Analysis where you will learn how to record your data in the Lab Notebook


*For references to this material, please visit Educational Resources


 
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