Lithium button cells, often called coin cells, are designated by their diameter and thickness in millimeters and tenths of millimeters, i.e. CR2032.

The proposal is that coins in circulation should be of regular sizes, i.e. 10mm diameter x 1mm thickness, 15mm diameter x 2mm thickness, this information being marked on the coin.

This would provide anyone with a handful of change with immediate access to a useful, reproducible measurement standard.
-- 8th of 7, Jun 03 2016

[+] Excellent idea. Did you know that the American One Dollar bill weighs exactly one gram?
-- r_kreher, Jun 05 2016


I like to tell people that the reason that a '99 (a type of ice-cream piped into a polystyrene cone from a criminal in an ice-cream-van and topped with a crumbly bit of chocolate) is so-called because the flakey chocolate, otherwise known as a "flake" is always exactly 99mm long and that the naming coincided exactly with both decimalisation and Margaret Thatcher (who invented whippy ice-cream of this nature prior to going on a crusade against flare-wearing hippies and other nerrdowells)*

* It should be noted that a proportion of the earlier statement, somewhere between 0 and 1, is utter bollocks.
-- zen_tom, Jun 05 2016


Likewise a sheet of A0 paper is exactly 1m² - so A1 is œm², A2 is Œm², A3 is 1/8m², A4 is 1/16m², and so on. When we start using 'A' paper sizes as currency things will all get a lot easier.
-- hippo, Jun 06 2016


...and so it follows that a sheet of 80gsm A3 paper weighs 10g (and this is easier to carry around than 2 litres of water, although I suppose you can drink the water if you're thirsty)
-- hippo, Jun 06 2016


... also known as "Euros" after Greece and a few more default on their sovereign debt.
-- 8th of 7, Jun 06 2016


//Did you know that the American One Dollar bill weighs exactly one gram? — r_kreher, Jun 05 2016//

Actually, no. That is a random fact that I just may pass on today if the subject arises. Cool. Thank you.
-- blissmiss, Jun 06 2016


Some coin facts I've found: 16 pennies stacked equals 1 inch and 16 pennies in a line equals 1 foot. 5 quarters weigh an ounce. A 1 yen coin weighs 1 gram, and has a radius of 1cm.
-- xaviergisz, Jun 06 2016


// represent the amount of quantity of energy they represent //

:<?
-- notexactly, Jul 03 2016


We wondered about that, too.

At one extreme, how much energy will "a shilling in the meter" buy you ?

At the other, substitute the mass of the coin into E=MC^2 ...
-- 8th of 7, Jul 03 2016



random, halfbakery