• Equipment and Setup
• TA Notes
• Data, Results and Graphs
• Answers to Questions
• Lab Manual
• CUPOL Experiments

The experiment use the following eauipments (see Figure 1): Hollow tube, stop watch, nylon string, rubber stopper, 20 steel washers, alligator clip, meter stick. A shortcut of the stop watch program is on the desktop, the program can be found at: "Lab Program" --> "207 labs"--> "stopewatch" (Figure 2). You may also use An on-line stopwatch. When using the stopwatch to measure the time for one revolution, it is better to count the time for 30 revolutions and devided it by 30, thus minimize the error compared to just taking one or few revoultions. Before the lab, check that all tubes are smooth on the top end. Replace the tube if necessary (Figure 3). Adjust the string to let the distance from the center of the rubber stopper to be 50 cm. Place the alligator clip on the string 3 cm from the bottom of the tube (see Figure 4). Don't put the washers on the clamp, instead, they should be put on the string (see Figure 4). Be sure that the weight of the clamp is also included when you use the balance to the measurement.

[Click on images to enlarge.] 1 2 3 4 3

• As usual, perform the experiment ahead of time!
• Tell the student to watch out when they swing the the stopper. Don't hit anybody!
• You may wish to remind the students the difference between the "M", which represents the mass of the rubber stoppers, and the "m" of the steel washers.
• Make sure that students swing the the stopper in horizontal circles, not vertical circles.
• Maintain the "3 cm" mentioned about (Figure 4) during the swinging.
• Accurate revolution period measurement is critical to the experiment. Let the students take as many measurements as necessary to get the value of a period. When doing this, they may do better if they use some physical backgroud as reference to count the number of revolutions.

Enter TA password to view sample data and results of this experiment:

The Lab Manual for this experiment does not exist on-line.

Take a look at these CUPOL experiments for an on-line laboratory experience:

• Vernier caliper tutorial