CBL
Lab 11

Simple Oscillations: Masses on Springs 

You will explore the relationship between the period of oscillation and the mass of an oscillating object.

TI-83 Calculator

Motion detector with CBL adapter

TI CBL with ac adapter

TI link cable

SPRING program

spring (stretch of about 4 cm per 100 grams suspended)

set of masses (50g increments)

mass pan (50g) to support masses

ring stand and cross bar

index card and tape

1. Attach the cross bar near the bottom of the ring stand so that the bar hangs over the edge of a table.

2. Hang the spring from the bar and secure with a small piece of tape so it can’t slip off.

3. Hang the 50g mass pan from the spring and gently add an additional 300g. Make sure the pan can’t slip off the spring and the masses can’t slip off the pan and hit the motion detector.

4. Tape an index card to the bottom of the mass pan so the motion detector can "lock on".

Place the motion detector face-up on the floor directly below the hanging mass. Make sure the detector and pan are separated by at least 60cm but no more than 1.00m.

5. Attach the calculator to the CBL with the link cable.

6. Plug the motion detector with adapter into the sonic port of the CBL.

7. Plug the CBL ac adapter into the wall outlet and turn on the calculator and CBL.

1. Press the PRGM key on the calculator and select the SPRING program.

2. Press ENTER to begin the SPRING program.

3. Follow the directions in the program to collect the motion data. (To set the mass into oscillating motion, carefully lift the suspended mass a few centimeters straight up and then gently release it. Make sure there is no side to side motion.)

4. In a few seconds, a graph of position versus time will appear on the screen. The graph should like sinusoidal (i.e., like a wave). The motion data is saved in lists L1 and L2 of your calculator.

Simple Oscillations Period:___________ Date:_______________

1. Once you have the waveform saved, you need to calculate the period (i.e., time for one complete oscillation ) of the mass. In order to obtain the most accurate measure of the period, how many complete cycles should be used for the calculation--only one or several? Why?

2. Hit TRACE and follow your teacher’s instructions to determine the time it takes for one complete cycle. Draw and label a diagram that shows the full screen and clearly denotes the two cursor positions you used to determine the period. Show your calculation of the period.

3. Remove 50g from the spring and repeat the data collection. Find the new period of the oscillation. Enter your data in the table below. Continue this process down to 100g. The mass data is already typed in for you. Use the period value` to calculate the frequency of oscillation in each case.

4. Clear lists L1 and L2 on your calculator. Enter the mass data in L1 and the period data in L2.

5. Follow your teacher’s instructions to create a plot of the mass and period data. Carefully sketch your graph below. Be sure to label the axes.

6. Describe the shape of your graph. Is it linear? curved? sinusoidal?

7. Look in your text book to find the mathematical relationship between period and mass for a mass on a spring. Write the relationship below. How does this relationship explain the shape of your graph?

copyright 2009 The North Carolina School of Science and Mathematics