Reliable ––- Errors
Readings should be repeated to identify anomalies and thus increase reliability
Errors
human error problems with our own human fallibility
systematic error problems with the system of measurement and/or the equipment
random errors inconsistencies in the way the measurements are done
Try these 3 experiments to measure TIME
Expt.A
Use your stop clock to find the time for one and only one complete swing. This is called the PERIOD of the pendulum
Record attempt 1 in the table as shown below
Repeat this measurement three more times
Put all results in a neat table as shown, indicating how precise your readings are
Record each measurement to an appropriate number of significant figures
| Expt | Attempt | Time / s | Sig. Figs. |
|---|---|---|---|
| A | 1 | +/- | |
| 2 | +/- | ||
| 3 | +/- | ||
| 4 | +/- | ||
| B | 1 | ||
| C | 1 |
Results
Expt. B Find the time once and only once for 5 complete swings. Calculate and record the Period.
Expt. C Find the time once and only once for 20 swings. Calculate and record the Period.
Expt. D Find the time once and only once for 50 swings. Calculate and record the Period.
Questions …. To be answered in full sentences:
What sort of error occurs in each of the above expts, and why ?
If you had to choose a number of swings to find a reliable value for the Period, is there an optimum number of swings to use, and why ?
Extension if time:
Refer to your “How science works” sheets … how could you reduce each of the errors:
-
human error ?
-
systematic error?
-
random error?
-
anomalous values?
Apparatus: Stopclock. Simple pendulum.