The scale does is not a factor of the Coriolis force. The magnitude of
the force is constrained by latitude and speed of matter. It is a force

stemming from the inertia of mass having a rotational spin placed on it

by the motion of the earth so it affects all matter even the water in
your sink.

The scale does not affect the apparent "force" - but the Coriolis
effect is only significant with large scale circulation, mostly because
the larger scale allows the time necessary for the earth's spin to have
its apparent effect. For small containers under normal circumstances,
it is still mathematically insignificant.

If you don't believe me then you can do this experiment yourself. Fill a
sink with water and after it is very still open the drain without
disturbing which way the water spins down the drain. Do it a couple of
times and you will notice a tendency for the water to spin clockwise.

I have tried this. Unfortunately, I do not have a perfectly round
sink, nor was I able to get a perfectly still pool (we have enough
close truck traffic so that ripples can appear at most any time in a
basin of water). The results were inconclusive - but the results bore
on whether the system was perfect enough, not whether the Coriolis
effect is real (it is). Besides all that, if the Coriolis effect were
large, the rotation would show up fairly quickly even when the drain
remained closed. The fact that it requires both a perfectly still pool
and the added energy of a draining basin to make a showing says
something about its magnitude.

One interesting fact about it that nobody grabs onto is that in the N.
hemisphere, the Coriolis vector does not shift a wind to the left
(counterclockwise) but rather to the right (Clockwise). It is the
combination of the wind direction, its friction with the ground, the
locations of the high and low pressure areas, and the Coriolis vector
that determines rotation. Without the potential energy added to the
system by the pressure gradient, even at medium scales the Coriolis
vector would have a relatively small effect...and the effect would be
clockwise (!).

Bruce Jensen