A friend of mine a long time ago,(this chap was a bit of an eccentric) said that everything should be measured and thought of in Snickers or mars bars, these have been the same for so long everybody knows you exactly what they are, if somebody asks how far is it from A to B and you replied 300 snickers they would know exactly how far it is, same with weight, how heavy is that? 200 snickers, no more lbs, inches, mm, kilometers it would be much easier.
Great, but when I was in the US in 1988 I was confused because we then called the Snickers a Marathon (but now its a Snickers). And a US Milky Way was what we called a Mars Bar (and still do). Probably the same length though.