Ib Lab - Torsional Pendulum (d Dcp Ce)

International Baccalaureate Physics

4/PSOW

Torsional Pendulum Design Lab Aim: The time period of a pendulum was first investigated by Christian Huygens in the 17th Century (after apparently observing a swinging chandelier in church). From Huygen's work the first accurate clocks were invented and refined You may be very familiar with traditional swinging pendulums and the variables that do and do not affect their time periods. In this design lab, you will learn about the workings of a torsional (twisting) pendulum. Diagram:

IB Criteria Assessed Design, Data Collection and Processing, Conclusion and Evaluation Criteria assessed

Aspect 1

2

3

Level awarded

D DCP CE

Apparatus: •

A torsional pendulum made from a 30cm acrylic ruler and elastic band (shown opposite)

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Anything else you might find in a normal physics classroom.

Design: Design a procedure to test how a certain variable (of your choice) may affect the rate of an oscillating torsional pendulum that includes appropriate use of apparatus for the control, collection and analysis of data. As always, this should design lab should include: • • •

Defining the Problem and selecting variables: Controlling the Variables: Developing a method for collecting data:

Step by step instructions and diagrams are helpful to the reader and highly recommended. Also include a quantitative hypothesis for your investigation together with a sketch graph of what you think will happen. Note: It is important to realize that the period of such a pendulum is NOT the time of one revolution, but instead the time taken for a stationary twisted pendulum to spin in one direction, stop briefly, and then wind itself back up. This completes one cycle. Data Collection and Presentation: • Record the raw data (both quantitative and qualitative) for the experiment in a suitable form. Include uncertainties due to the precision of the measuring apparatus. • Process your quantitative raw data. • Present the processed data in a appropriate way and include errors and uncertainties Conclusion and Evaluation: • Draw conclusions based on your interpretation of the data. Include a comparison of your results with any published data regarding torsional pendulums. Compare your results with your original hypothesis. • Evaluate your own plan, including any weaknesses and/or limitations. Include an evaluation of the apparatus used. © Dingrando - ISM 2009

15614017.doc

International Baccalaureate Physics

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4/PSOW

In light of the weaknesses and limitations suggested above, suggest ways in which the procedure could be modified in order to improve it for the future.

The above information was given to the student by the instructor. What follows immediately below is the student’s own work.

© Dingrando - ISM 2009

15614017.doc