[SquarishTriangle (OP)]

Wasn't sure if I should put this in General or Chat, but I can't help thinking that theoretically, it'd be relatively simple to control which balls are drawn from the pool in most television lottery set ups. I don't watch these a lot but from what I've seen, it seems like they start with the balls in a FIXED rack, which roll into a FIXED container (usually a spherical one), with a mixer with FIXED arms moving at a constant rate around a single axis.

So as long as you start the arms of the mixer at the same position each time, and time the drop of the balls the same, doesn't the only variable become the position of the balls in the rack (ie. if the first ball drawn was in column A, row 2 and the second ball in column B, row 3 etc...whichever balls are in those positions in the next draw will be first and second again)? And then you can put whichever balls you like into the positions you know are going to result in the ball being drawn?

Does that make any sense? Or am I missing something?

[graham.d]

I think it is likely that the random effects within the system will dominate after quite a short time. From a practical point of view, I believe these systems, primitive though they may seem, have been tested extensively for the randomness.

[DoctorBeaver]

I would imagine Chaos Theory comes into it.

[Bored chemist]

Since it's the same rig used each time, and they use it in the same way, presumably the same numbers come up each wekk.

[lyner]

The Victorians thought that it was only a matter of time before you could work out what would happen to any system in the future if only you could measure initial conditions accurately enough. How wrong can you be?

[Bored chemist]

It seems you start of slightly wrong, but you rapidly get even more wrong.

[lyner]

Qm implies that you don't have much of a clue, even at the start, usually.

[SquarishTriangle (OP)]

I would imagine Chaos Theory comes into it.

Qm implies that you don't have much of a clue, even at the start, usually.

Sorry, I don't have much of a grasp of those concepts (and no I don't expect you to explain chaos theory to me).

What I'm getting it that small variables are bound to occur with each run of the system, and these changes affect other objects within the system triggering a chain of consequences that accumulate and the increasingly deviate from the 'predicted'...resulting in randomness between the results of each run (?). And that it can't be controlled to a point where randomness can be rendered practically insignificant?

Presumably those boring, aged-looking people who sit on the desk during the draw would actually prevent any deliberate ordering of the balls from occuring in any case.

So are we saying possible, possible but unlikely, or so unlikely that possibility is negligible?

And if I tested the system a huge amount of times, controlling variables at tightly as possible to produce a large data set, is it possible to then predict the result of the draw from the initial position of the balls using patterns in the results?

[Bored chemist]

Imagine that you knew the exact path and weight etc of all the balls except 1 at the start.Also, imagine you have a fast computer (or enough time on your hands to calculate exactly whay would happen from one moment to the next (and I'm ignoring the QM side of the problem here.)
You would be able to make a computer model of what would happen; now remember the 1 ball that's a bit wrong.
After a few tenths of a second or so, according to your model it should hit some other ball at a particular point but, because it isn't quite right to start with, it misses so you now have 2 balls that are not quite behaving as you expected. Another bounce later and the 2 balls that were wrong are still wrong and they have also missed the expected balls so now there are 4 that you don't know the properties of.
Every few tenths of a second or so the number of "wrong" balls doubles so, since there are only about 64 balls in total it only takes half a dozen bounces or so and you have no idea what any of the balls is doing.
A second or so is enough to scramble the balls and they stir them for a lot longer than that.
This problem where a small change in the initial conditions rapidly becomes a big change in the final condition is characteristic of "chaotic" systems.
The weather is probably the best known- imagine that, instead of a few dozen balls you are dealing with all the molecules in the atmosphere and they bump into eachother at roughly the speed of sound.

[turnipsock]

You could apply this concept to a roulette wheel. It's a lot simpler.

[rosalind dna]

You could apply this concept to a roulette wheel. It's a lot simpler.

You could apply this concept to a roulette wheel. It's a lot simpler.

LOL LOL LOL LOL

[that mad man]

Randomness is also produced because they use ping-pong balls.

I doubt that any 2 would have exactly the same properties of bounce as they are not produced to be that accurate, very close but not exact. They are hollow and after a while of use they lose some bounce and have to be changed, ping-pong players would confirm.

Any change in temperature in the studio when it takes place I think would also affect them.

[turnipsock]

The time from the balls being realeased to the guy pushing the button, and wishing us all luck, is a variable.

[Bored chemist]

I think the NPL actually check the lottery balls for QA purposes.
http://www.npl.co.uk/server.php?show=nav.376