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Pendulum Lab

Raw Data

Null Effect of Mass

Null Effect of Amplitude

Period vs. Length

There is a visible curve to the data, so we are on the right track with our deduction. But can we prove the equation definitively???

Pendulum Lab – Proving the Deduced Equation:

Log Rules: 1)

2) log(mn) = log(m) + log(n) 3) log(m/n) = log(m) – log(n) 4) log(mn) = n · log(m)

)log(10 xx

Pendulum Lab – Proving the Deduced Equation:

We set out to prove that the period, T, of a pendulum was given by the equation:

glCT

, and that mass and amplitude have no effect on T. In addition, we also want to determine the constant, C. With the data we have taken, we have the information we need to do this!

Pendulum Lab – Proving the Deduced Equation:

This equation, gLCT is the same thing as saying that,

If we plot Log T vs Log L and our deduction is correct, then the slope of the line should be ½!!!

5.0Lg

CT

g

CKKLT where,5.0

KLT

LKKLT

loglog5.0log

loglog)log(log 5.05.0

b mx y

Period vs. Length

Pendulum Lab – Proving the Deduced Equation:

After plotting the Log T vs. Log L and fitting a line to the curve, we now have an experimentally determined equation that can be used to validate our deduced expression. This equation can also be used to help us determine the constant C. Can your team figure out how this might be done???

Additional Questions:

1. What were your method(s) for extracting

accurate data in the face of difficulties you

encountered?

2. Using the data you obtained extrapolate the

length of string required for the period of

oscillation of the pendulum to equal 2 seconds.

Explain your process and show all work.

3. Assuming that the constant C equals 2π, find a

best-value for the acceleration due to gravity.

Explain your process and show all work.

Pendulum Laboratory Report

1.Format: 10% 2.Objectives and Procedures: 30% 3.Analysis of results: 30% 4.Error analysis: 10% 5.Questions answered 20%

Sample Lab Report: http://www.writing.engr.psu.edu/workbooks/labreport2.html (Only difference is that you need to include data plots in the

body of your report, not just as an appendix.)

Grading Rubric:

Pendulum Laboratory Report

1.Format: 10% • Title Page • Introduction • Objectives • Materials • Procedure • Data • Analysis & Discussion of Error

Sample Lab Report: http://www.writing.engr.psu.edu/workbooks/labreport2.html (Only difference is that you need to include data plots in the

body of your report, not just as an appendix.)

Grading Rubric:

Due Date: 10/13/10 10/14/10

10/18/10 Final Due Date: 10/22/10

Pendulum Laboratory Report

3. Write-up a) Typed, 12 pt font, 1.5 spacing b) 3-5 pages long, not including appendix of data tables c) Separate report into sections d) Answer #1-3, making sure to cite all sources used

a) Describe the purpose of experiment b) Describe the experiment and method c) Describe the results

Include data plots and a description of what they tell you – based off objectives

d) Describe possible errors that led your results to be different from the theoretical values

Pendulum Laboratory Report

3. Write-up (continued) e) How do your graphs and results support or refute

the theory of a simple pendulum? Your purpose here is to discuss, in writing, what evidence there is that indicates (or does not indicate) that the theory is correct. Do not do any calculations for this question. Instead, refer to the shapes, features, and types of relations and equations shown on the graph(s). Be sure to discuss each part of the lab.

Pendulum Laboratory Report

1.Format: 10% 2.Objectives and Procedures: 30% 3.Analysis of results: 30% 4.Error analysis: 10% 5.Questions answered 20%

Sample Lab Report: http://www.writing.engr.psu.edu/workbooks/labreport2.html (Only difference is that you need to include data plots in the

body of your report, not just as an appendix.)

Grading Rubric: