Preparing for Lower Sixth Physics #19: Precision

The sign says 7 3/4 miles to Sebergham. Ah, fractions! We don't usually use them in Physics. We like decimals because a decimal will tell you the PRECISION of the measurement. Let's go with 7 3/4 metres because it breaks down more easily than it would in miles. 7.75 m would mean it was measured to the nearest centimetre. 7.750 m might seem the same but it actually shows that I measured to the nearest millimetre, which is clearly more precise. So please start using decimal fractions to show the correct precision of any measurement.