# The Law of Coin Pressure

I remember have this strange theory that is usually true. I might have even mentioned it on this blog before maybe even blogged about, but this is a post entirely devoted to this funny subject.

In a contracted form, it simply says this: The more coins or small change you have, the more likely you are to give them out - and the less likely you are to receive them. I call it "coin pressure" as a reference to air pressure. Air flows from high pressure areas to low pressure areas - and so do coins. This is typically the case when you go out with friends.

Imagine the case where you go out with friends to eat. Being students, going Dutch is standard practice. There is no arguing over who pays the bill. Everyone pays the bill. Now, some places do cater to students and allow you to pay separately for items on the bill. This means that there is conversation going: "You owe this much from that, and you're supposed to pay for that, and I'm supposed to pay for this."

Usually you relegate this calculation to the accounting major students by just using the excuse that usually goes: "Let's give this to the accounting majors to sort out." In real life, there's probably a better mental mathematician at the table than the accountants (in fact I think in our case it was a management major student) - but hey, anything to not do the work. :P

After it gets sorted out, then everybody gets the numbers. Sometimes the numbers can get pretty bad change wise, for example, $8.90 per person. That means to pay exactly, you need one$5 note, one $2 coin, one$1 coin, one 50c coin, and two 20c coin - and that's already the simplest possible. 6 pieces of change to pay off your bill.

Of course, if you have the change, you just pay your part. If you don't, you take on more and more change - in general, the bigger the currency note you have to pay with, the more change you will have to carry when you leave. It follows that the opposite holds true, the more small change you have, the less small change you will have to carry when you leave. (Hence, the origin of the law.)

There is the largest possible denomination of currency - a credit card. If you are paying the bill on behalf of the table by credit card, then you effectively collect all the payment by everyone else - since you had the lowest "coin pressure".

Of course, there is such a thing as too much coin pressure. If you carry around 200 5c coins just so that you will always have enough coin pressure to pay off any possible bill within \$10 - nobody will want to have to split a bill with you. :P

Moral of the story?

Carry a good variety of coins and small notes with you.

Try to never leave any coins at home unless it's in your piggy bank. Coins at home have this bad habit of accumulating to ridiculous numbers since you leave more and more and home - and leaving coins at home reduces your coin pressure, hence increasing the probability of you receiving even more coins.