Errors

The students are required to have an appreciation of the errors inherent in practical work and the precautions that should be taken to reduce such errors.

No quantitative treatment of errors is required.

There are many causes of error in physics experiments:

observational error

one of the most important errors when reading values is called the error of parallax

instrumental errors,

such as zero error on a micrometer screw gauge or a meter; adjustment errors, such as an incorrectly adjusted spectrometer;

Students need to understand the difference and the appropriate precautions taken to reduce them.

Students should appreciate that a measurement has a certain level of error, and the concept of percentage error could be mentioned, although calculation is not required. Students should appreciate that the measured value may be different from the accepted value for the quantity.

zero error is an easy error to avoid.

just make sure the mass balance, multimeter, etc read zero before they are used to measure any value. With a multimeter reading resistance there might be some residual resistance of the test wire. Thus to overcome this minor inaccuracy the resistance of these wires should be measured before doing the experiment. The value obtained here must be subtracted from the experimental reading in order to improve the accuracy of the experiment.

For more details on the zero error http://physics401.one-school.net/2009/01/140-measurements-and-error.html