Coins

So a discussion recently on %afda on coins... led to this essay/analysis/something, whatever this turns out to be.

So, let's introduce the players...

Notes regarding the images:

• They are all to scale - in fact, they are all cropped from a single scan at 100dpi
• The diagonal stripes are artifacts from the textured plastic sheet I protected the scanner from the coins with. (I wasn't going to lay chunks of metal directly onto brand-new scanner glass now was I?!). Besides, these images are more about relative size than relative design.

North American coins

http://www.nut.house.cx/~nemo/extras/coins/us_1cent.jpg http://www.nut.house.cx/~nemo/extras/coins/us_5cent.jpg http://www.nut.house.cx/~nemo/extras/coins/us_10cent.jpg http://www.nut.house.cx/~nemo/extras/coins/us_25cent.jpg http://www.nut.house.cx/~nemo/extras/coins/us_50cent.jpg http://www.nut.house.cx/~nemo/extras/coins/us_1dollar1.jpg http://www.nut.house.cx/~nemo/extras/coins/us_1dollar2.jpg

• USA Coinage
  • 1 cent (penny)
  • 5 cent (nickel)
  • 10 cent (dime)
  • 25 cent (quarter)
  • 50 cent (half-dollar)
  • 100 cent (susan B or golden-dollar)

http://www.nut.house.cx/~nemo/extras/coins/ca_1dollar.jpg http://www.nut.house.cx/~nemo/extras/coins/ca_2dollar.jpg

• Canadian Coinage
  • 100 cent
  • 200 cent

Australian coins

http://www.nut.house.cx/~nemo/extras/coins/au_5cent.jpg http://www.nut.house.cx/~nemo/extras/coins/au_10cent.jpg http://www.nut.house.cx/~nemo/extras/coins/au_20cent.jpg http://www.nut.house.cx/~nemo/extras/coins/au_50cent.jpg http://www.nut.house.cx/~nemo/extras/coins/au_1dollar.jpg http://www.nut.house.cx/~nemo/extras/coins/au_2dollar.jpg

• • 5 cent
  • 10 cent
  • 20 cent
  • 50 cent
  • 100 cent
  • 200 cent

European coins

Have a look at wikipedia at http://www.wikipedia.org/wiki/Euro_coins -- they are very detailled about the Euro coins and display the Euroland standard backsides as well as all 15 sets of national frontsides.

Misc others

http://www.nut.house.cx/~nemo/extras/coins/ja_1yen.jpg http://www.nut.house.cx/~nemo/extras/coins/ja_10yen.jpg http://www.nut.house.cx/~nemo/extras/coins/ja_50yen.jpg http://www.nut.house.cx/~nemo/extras/coins/ja_500yen.jpg http://www.nut.house.cx/~nemo/extras/coins/uk_1pound.jpg

• • Japanese 1yen
  • Japanese 10yen
  • Japanese 50yen
  • Japanese 500yen
  • UK 1pound

Analysis thingy

"Analysis thingy"?! I've been watching too much Star Trek I have that's what's going on. Report Mister Data.

So the discussion underway at the time was about how the USA should consider dropping the penny (on the basis that it's effectively meaningless as a coin in it's own right, and only used for trivial tipping or changemaking). As many other countries have shown in recent times, low denomination coins can be dropped and rounding take up the slack. In fact, even the USA used to have a half-cent coin in the early 19th century.

Discussions also abounded as to the 'greedy algorithm' of changemaking as used by cashiers (especially in america it seems), and then moved onto the rarity of use of the USA 50c coin.

It was noted and agreed by all that the USA 50c coin is bulky in size. Even I noticed this while I was there... and yet, when I came to compare, the australian 50c coin is even larger yet again!

The Australian 50c coin is, however, widely and commonly in use, and whilst I wasn't around when Australia currency moved to decimal, I've certainly never heard complaints that the 50c coin is bulky. Indeed, the original 50c coin was slightly smaller and round, but was often confused for a 20c coin for that reason. After only a year or two, a new 50c coin was introduced with the 12sided shape and (I believe), very slightly larger size. This coin has now been standard in Australia since the late 1960s.

So why would I think the smaller USA 50c coin bulky whilst the Australian 50c is not?

I believe the answer is due to the relative sizes and values of other coins. The first minor note to consider is that the Australian 20c coin is larger than the nearest equivelant American coin - the 25c quarter (which is, in turn, almost the same size as an Australian 10c coin. Note to Americans, the US 10c coin is about the same size as our 5cent coin, which is our smallest coin - both physically and economically. Thus Australians are a little more used to carrying larger coins around with us.

More importantly, I believe, is the proportional size between coins. In Australia, to carry 50cents, the least bulky way is with a single 50c piece. The next best way is with 2x 20c and 1x 10c piece. Then 1x20c and 3x10c, next 5x10c, and finally 10x5c. Thus there is always a benefit to desiring the higher denomination coin, for economy of carrying reasons. By comparison, there is no such incentive to desire a USA 50c coin. The next coin down - the 25coin, is significantly smaller, and it's easier to carry 2x25c than 1x50c. I suspect a similar reason would be behind the relative scarcity of 5c coins I saw in the USA - the increase in carrying efficiency in 1x10c compared to 2x5c is so huge for USA coins, that nobody desires a 5c coin.

A note on relative thickness - the Australian $2 coin and then the Australian $1 coin, are the two thickest I immediately see in my sample here. Followed (in my estimate) by the Australian 50c coin, the Australian 20c, American 5c, American 100c, American 50c, American 25c, Australian 10c, American 1c, Australian 5c, American 10c. (note that the only coin in my sample in total that was thicker than any of these, was the UK 1pound coin)

So, I can see why Americans love their quarters - they pack the best economic worth into the smallest package, and are conveniently easy to carry.

Of course, with inevitable inflation, the quarter isn't as economically usefull as it once was... but that's another story.

On values available

North American coins seem to have been chosen on the basis of breaking a dollar down. ie, start with your 100cent dollar, and halve it to get a 50c coin. Then halve your 50c to get a 25c coin. Half again... and 12.5c doesn't make sense, so round it down to 10cents. Halve to 5cents, then halve (and round down) to 2 and finally 1. The american 2cent coin has since been abolished (actually, I've never even heard of it before now, and not tracked down any evidence of it, but that's an aside). By comparison, Australian coins seem to be created on the basis of building up from 1. 1c doubled is 2c. Doubled and rounded is 5, doubled is 10. Repeat for 10c, then for 100c (in note form as it happens). The result - Australia has (or had) a 2c, a 20c, a 200c, a 2000c coin or note. America has a 25c, 200c, 2000c... this lack of consistency across the scaled of large values ot small values makes it harder to learn a consistent single system of change and coinage, thus leading to increased adoption of the 'greedy algorithm', even when such an algorithm doesn't nescessarily lead to the most efficient bundle of change.

Aside from the cash value and size considerations, let us consider the role of coins as a place to display national symbols. There are eagles on the quarter and dollar coins. The other sides of those coins are the father of the country (quarter) and the guide that introduced the white man to the western half of North America. The patron saint of the Republican Party is on the cent, the only statue to face that way in common use until Sacajawea came along on the new dollars. It could be argued that the patron saint of the Democratic Party is on the dime. (If that is true, there is nine cents difference between the partys from a small change point of view...) What does it mean that the guy who wrote the Declaration of Independance is on the nickel?

Trivial observations

In Australian, Canadian, UK and Japanese coins observed, the "top" of the coin is always at the same point on both sides. That is to say, if you spin the coin left-to-right, both sides face up. American coins have the "top" of each side at different ends of the coin however - meaning you need to flip the coin top-to-bottom to view the other side right-way-up.

The Queen appears to be common to all commonwealth coins that I've come across (Australian, New Zealand, Canadian), and the design is identical. She faces right. By comparison, the head on almost all American coins faces left. As noted above, the 1cent and the new $1 coin are exceptions to this.

External Links

• http://www.ramint.gov.au/making_coins/coin_designs.cfm - has details on designs and exact diameter sizes of australian coins.
• http://www.mintsoftheworld.com/index.html - List of world mints.
• http://www.usmint.gov/faqs/ - ask it about size for an explanation of why the nickel is larger than the dime. (summary: it was originally smaller, due to it's silver content being proportional to other coins, but it was TOO small, so they made it bigger with an alternative metal - leading to the modern nickname of "nickel")