-- Teacher Notes

The purpose of this activity is to use the Stella model for a mass oscillating when attached to a horizontal spring to investigate the effect of the amplitude on the period of the oscillation.

Preliminary Questions:

1)     What effect do you think starting position will have on the period of oscillation?  In other words, if a mass on a horizontal spring is stretched greater and greater distances from its equilibrium position, will the period of oscillation increase, decrease, or stay the same?

·        The period of oscillation is independent of the release position of the mass.

·        The period of oscillation is independent of the release position of the mass.

3)     Describe a procedure that you could use to investigate question 1 using the Stella model built to represent a mass attached to a horizontal spring.

·        Vary the starting position several times and check the period of oscillation.

Investigation:

Carry out the procedure you described above investigating the effect of amplitude on the period of oscillation.  Collect and record results in a careful, organized manner.  Make sure to collect enough data to perform reliable mathematical analysis.

Analysis:

Graphically analyze your data in order to determine a mathematical interpretation of the data.  Record or print out your results.

Conclusion:

Write a summary of this investigation.  Be sure to describe your experimental procedure and to express what effect the amplitude has on the period.

Teacher Notes:

The purpose of this activity is to verify results obtained from the Stella model regarding the effect of amplitude on period. In this lab the system will consist of a low friction cart attached to a horizontal spring.

Materials Needed

Spring

Low friction cart

Stopwatch

CBL/MBL and motion detector probe

Procedure:

Design an investigation to verify the relationship between amplitude and period that you discovered using the Stella model.  Describe the procedure.

·        The basic procedure will be to vary the position that the cart is pulled back from equilibrium, and measure the associated period of oscillation.  While it is possible to measure the period of oscillation using a stopwatch, the data will likely be plagued with experimental error.  This is a lab for which a motion detector really enables taking data that supports the conclusion we would like to see the students arrive at.

Investigation:

Carry out the procedure you described above.  Collect and record results in a careful, organized manner.  Make sure to collect enough data to perform reliable mathematical analysis.

Analysis:

Graphically analyze your data in order to determine a mathematical interpretation of the data.  Record or print out your results.

• The line-of-best-fit will be a straight horizontal line, showing that the period is not dependent on the amplitude.

Conclusion:

Write a summary of this investigation.  What physical quantities are changed when the amplitude is varied? Describe the relationship between the quantities that are affected and the amplitude.

• When the amplitude is increased the force is increased, initial velocity is increased, and acceleration is increased.  The period stays constant.