Die question

[Mole]

Must the sum of the opposite sides of a die all equal each other?

This question arose recently when an acquaintance claimed the sums of the opposite sides of a 6 sided die HAD to equal 7 else it was unbalanced. Another person argued that as long as each number was represented only once, the die would be balanced. I'm curious if there is indeed a reason for it or if it's just tradition.

[Crowbar of Irony +3]

I don't think the number of spots on the face of the die determines its balance. I could have six "6s" on the same die and each of the six has one in six chance of coming up...

Or so my common sense tell me..

[Cillasi]

I found this:

Casino dice are different from dice used in board games. Casino dice (also called precision dice) are primarily red and somewhat transparent. Casino dice have to be as square as is technologically possible so as to be fair to both the casino and the players. Dice used in board games are crudely manufactured and always favor the higher numbers (4, 5, and 6) because more material is drilled out of those sides.

at this site: http://www.diceman.net

So, it seems that the weight/balance of a die is important. I'm sure there is more to it, and there is a lot of interesting information on the above site.

[MC Master of Ceremonies]

It's just tradition, if the dots affected the balance there'd be an imbalance between the side with the six and the side with the one.

[ifitmovesitsbiology_198778]

if they weren't equal then the balance would not be affected, but it may affect the fairness.
Have you ever noticed how certain numbers come out more when playing a game with a dice. If the numbers on a dice were in a different order then this would suggest that a different number would come out more. Like a 2 in stead of a four.
It could possibly affect the balance slighty as the dots may have some bearing on the weight, but not much.

[Cillasi]

At same site, I also found this in section about making dice.

Next come the spots. First, the spots on every opposite side should equal seven. That is, the side with three spots must be opposite the side with four spots, the one spot opposite the six spot, and the two spot opposite the five spot. Spots are made in many different styles: solid, bulls-eye, birds-eye, doughnut, and several more. The spots are filled in with special paint that weighs the same as the plastic that was drilled out for the spots. This insures that each side of the cube weighs exactly the same.

[friedo]

If the special paint weighs the same as the plastic, and each side weighs the same, what is the point of having the sums of the opposite sides all equal seven?