Uncertainty for calculating period
(3.80s±0.02s)/5 = (3.80±0.53%)/5
= 0.76±0.53%
= 0.76s ± 4.03x10-3s
Graph 1. Period per Length
The period of the pendulum could be calculated with the formula;
Where T is the period, l is the length of the pendulum in meters, and g is the gravity which is 9.81m/s2.
Table 5. Theoretical Values
Uncertainty for theoretical value of the period
Multiplying and dividing absolute uncertainties
T = 2 x pi x (0.10/9.81)1/2
= 2 x pi x (0.10m±0.01m/9.81)1/2
= 2 x pi x (0.10±10%/9.81)1/2
= 2 x pi x (0.0102±10%)1/2
= 2 x pi x (0.1±10%)
= 0.63±10%
= 0.63s±0.063s
Table 6. Comparing the Gained Data and Theoretical Data
The formula that was used above to calculate the period is then derived into lengths over period squared to gain the constant gradient.
Table 6. Time per Lengths
Conclusion and Evaluation:
There was an effect on the period of oscillation of the pendulum when the length of a pendulum was changed and the angle of oscillation was constant. As the length of a pendulum got longer, period of oscillation of the pendulum took longer compare to shorter length of a pendulum.
Table 3 is data calculated from the raw data in table 2 and the average time taken calculated is for five oscillations that were being measured during the experiment and the time taken for each period is then shown in table 4. Graph 1 is showing the linear graph when period of each lengths were plotted and the y = 1.9x + 0.564 graph was gained. Table 5 is the theoretical values that were calculated from the formula;
Then in table 6, each gained data and theoretical data were compared by calculating the percentage difference between them. There were only small percentage difference between gained data and theoretical data for lengths of 0.2m, 0.3m, 0.4m and 0.5m. On the other hand, for 0.1m, percentage difference was more than 20 percent even though there were only 0.13seconds difference between the theoretical value and the gained value. This maybe because of the systematic and random errors occurred in the experiment created bigger uncertainties than other values as the 0.1m values are small numbers.
Through out the experiment, there were equipments’ uncertainties frequently being carried out and also there were number of random errors and systematic errors also being carried out. Firstly, the equipments such as stop watch and ruler created errors in performing the experiment. Secondly, random errors that were found during the experiment would be the air resistance, the swinging trend of the mass as the mass was not swinging in a straight line but swinging forming small thin elliptical shape and friction caused by the string and sticky tape connecting the mass and the clamp. Finally, systematic errors that were carried throughout the experiment would be the change in the length of the wire while tying the wire to the clamp and to the mass, error in using the stop watch as human cannot be exactly on the spot in reflex timing, change in angle of oscillation as there may have been uncertainties while measuring the angle and when person was releasing the mass from 10° angle, that person may have inserted force into the mass which gives more velocity to the mass which then affects the period of oscillation.
The experiment was performed several times per length of the wire to obtain more accurate results. While recording the data, unreliable data were not used in the calculations and only the reliable data were used to calculate the period of oscillation.
Improvements:
Table 7. Improvements