42 TechnologyNewsMeasurement units

Measurement units

So just how many London buses used to measure the height of Nelson’s Column would fit onto a football pitch?

We use many vague and interesting terms when trying to convey sizes and shapes and I thought it would be amusing to review some of the more unusual of these.

Old measurements often have interesting derivations and many original systems of weights and measures were based on real things. There really are some weird names such as the slug, barn and firkin. Others are a bit of a joke; the beard-second is defined as the length an average physicist’s beard grows in a second, which is then defined as 500 Angstroms, and the shake (as in two shakes of a lamb’s tail) has been defined as 10 nanoseconds, whilst a jiffy is less well defined as either 1/60 or 0.01 seconds!


We often hear that something is the thickness of a human hair, happens in the blink of an eye, or is as fast as a speeding bullet. None of these are real, historical, or accurate. British journalists frequently reference the length or height of a London double-decker bus (the acceptable maximum length and width has changed about 40 times since 1900!), another is the football field (which in the UK can vary in length and width, 90-120m long x 45-90m wide, and is different from those either in America, or Canada).

Newer technologies have added to the list. Computing has given us the bit, byte and nibble (as well as bugs!). Digital storage has evolved at a pace, we used to relate it to the number of A4 pages stored, now we readily consider the number of photographs, MP3s, or films.

Chillies on the Scoville scale

The engineering community doesn’t have a monopoly on strange units. Economists have used the cost of a Big Mac or Mars bar to refer to purchasing power, a measure of inflation or the cost of commodities and chefs have the Scoville scale for the hotness of chilli peppers!

We’ll award a bottle of wine to the weirdest real unit submitted to dave.wilson@42technology.com