Introduction

Taking accurate, reliable and appropriately precise measurements is very important for scientists.

Accurate - the reading is close to what is should be

Reliable - if the reading were repeated the same or a very similar figure is achieved

Precise - the number of digits with which a value is expressed

A thermometer reads 970C when put in boiling water. It is accurate?	A man stands on bathroom scales 3 times in 5 minutes. They read 88.0kg, 88.1kg, and 87.8kg. Are the scales reliable?	A digital thermometer reads 31.40C. How precise is it?

There will be errors in our measurements, both random and systematic. We should learn how to identify sources of error and account for them.

Random errors - these are unpredictable and result in different values for a quantity which is constant

Systematic errors - the difference between the measurement and the actual value is constant. Often due to a calibration error, e.g. a zero error.

When we have our table of results we must also present this data in such a way that the relationships between quantities can be identified.

We should also express the degree of uncertainty in our measurements, e.g. by using error bars.

In your A level Physics course you will learn these skills. You should also learn to take pride in your ability to take high quality measurements.

Near the end of the course you will be given an assessed task in which you should demonstrate these skills.