Pendulum Experiment
Conclusion:
Graphing the length against T2 clearly shows a linear relationship, in agreement with the theory. The actual line of best fit does not go through the origin(0,0) which suggests a systematic error in our experiment. When graphing a line of best fit, we find a line with a gradient of 4.128. Our value for ‘g’ can be calculated by dividing 4π2 with the gradient of the line of best fit; g = 9.56 m/s2 ± 0.6
Comparing our calculated value for the gravitational acceleration ‘g’ with the accepted theoretical value gives us an error of 2.5%, well within the error margins that we calculated. This is a reasonable result, given the equipment and the time constraints that we faced. Looking at our graph, we cannot identify any outliers. However, our data values suggest a line of best fit that does not pass through the origin. When we do fit a linear regression onto our data values, that passes the origin, we see that the line does not ‘hit’ all the horizontal error bars (the uncertainty in the length). This may suggest a systematic error in the measurement of the length of our pendulum. Furthermore, this experiment had to be carried out in about one hour, with very basic equipment. This, perhaps, contributed to the slight difference in the value for ‘g’ that we found.
Reference:
1. Practical Physics. 2009. The Swinging Pendulum [Online] Updated 22 October 2007. Available at http://www.practicalphysics.org/go/Experiment_480.html [Accessed 8 December 2009]
2. National Institute of Standards and Technology. 2009. The NIST Reference on Constants, Units and Uncertainty [Online] Available at: http://physics.nist.gov/cgi-bin/cuu/Value?gn [Accessed 8 December 2009]
Graphing the length against T2 clearly shows a linear relationship, in agreement with the theory. The actual line of best fit does not go through the origin(0,0) which suggests a systematic error in our experiment. When graphing a line of best fit, we find a line with a gradient of 4.128. Our value for ‘g’ can be calculated by dividing 4π2 with the gradient of the line of best fit; g = 9.56 m/s2 ± 0.6
Comparing our calculated value for the gravitational acceleration ‘g’ with the accepted theoretical value gives us an error of 2.5%, well within the error margins that we calculated. This is a reasonable result, given the equipment and the time constraints that we faced. Looking at our graph, we cannot identify any outliers. However, our data values suggest a line of best fit that does not pass through the origin. When we do fit a linear regression onto our data values, that passes the origin, we see that the line does not ‘hit’ all the horizontal error bars (the uncertainty in the length). This may suggest a systematic error in the measurement of the length of our pendulum. Furthermore, this experiment had to be carried out in about one hour, with very basic equipment. This, perhaps, contributed to the slight difference in the value for ‘g’ that we found.
Reference:
1. Practical Physics. 2009. The Swinging Pendulum [Online] Updated 22 October 2007. Available at http://www.practicalphysics.org/go/Experiment_480.html [Accessed 8 December 2009]
2. National Institute of Standards and Technology. 2009. The NIST Reference on Constants, Units and Uncertainty [Online] Available at: http://physics.nist.gov/cgi-bin/cuu/Value?gn [Accessed 8 December 2009]