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Experiment to find gravity from a Pendulum. Covers objectives:. P3 – demonstrate the ability to plot a linear graph using scientific data P3 – Calculate the rate of change by the most appropriate method D1 – determine the size and influence of errors on final calculations. Stage 1.
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Experiment to find gravity from a Pendulum Surya Tahir/BTEC National Diploma/Pendulum Experiment
Covers objectives: • P3 – demonstrate the ability to plot a linear graph using scientific data • P3 – Calculate the rate of change by the most appropriate method • D1 – determine the size and influence of errors on final calculations Surya Tahir/BTEC National Diploma/Pendulum Experiment
Stage 1 • Draw up a table with the following headings: Surya Tahir/BTEC National Diploma/Pendulum Experiment
Stage 2 • Set up equipment safely • Measure string at a short length • One person to time 10 pendulum swings • Partner to record data • Do this twice • Measure 5 different lengths of string Surya Tahir/BTEC National Diploma/Pendulum Experiment
Stage 3 • On graph paper plot length of pendulum (l) against T² • You should have 5 sets of data points • You can now work out the gradient by choosing 2 suitable points and calculating : T² / l Surya Tahir/BTEC National Diploma/Pendulum Experiment
Stage 4 • We can now find an estimate for gravity by comparing the formula for a straight line: Y=mx+c • With the formula for one complete oscillation of a pendulum: T= 2π√(l/g) Or T² = 4 π²l/g Surya Tahir/BTEC National Diploma/Pendulum Experiment
Stage 4 continued.. • So gravity = • 4 π² ÷ gradient from graph Surya Tahir/BTEC National Diploma/Pendulum Experiment
Stage 5 -comparison • How close were you? • In the northern hemisphere.. • Acceleration due to gravity… • Is… • 9.81m/s² Surya Tahir/BTEC National Diploma/Pendulum Experiment
Stage 6 – Evaluation and write-up **Question 1 Work out the actual error and percentage error between your value and the actual value for gravity **Question 2 • Consider why we took values for 10 pendulum swings, and why this was done twice Surya Tahir/BTEC National Diploma/Pendulum Experiment