Beat me to this.
Water also drains clockwise and foucault pendulums process clockwise in northern hemisphere. These are somewhat less likely to have a bearing on the matter than a sundial.
Water also drains clockwise and foucault pendulums process clockwise in northern hemisphere. These are somewhat less likely to have a bearing on the matter than a sundial.
Whether or not it meets the standard of 'appreciable' is subjective i suppose.
I didn't watch this all the way through this time, but I do recall watching it back in 2017 when it was posted -- IIRC he did this experiment <sic>, asserting all variables were controlled for, but in a garage with leaky walls, on a poorly insulated floor, with no control test and only once, in one location.
Consider that hurricanes don't form within 5 degrees (~ 550km) of the equator - which gives a good indicator of just how strong (or not) the Coriolis effect is.
The tub they used was something like 60cm deep and 3 or 4m in diameter.
I can pull up the reference if you like.
It wasn't perfectly reproducible though; in classic fashion when they demonstrated for a local newspaper (Sydney Morning Herald) the water went the "wrong" way.
I have given the url / details here in HN a few years back.
Anyway, we're in agreement that it is a thing, and we just need a big enough tub to demonstrate it, correct?
The force is perfectly calculable, and we can compare that to the effect of, say, a breeze across the top.
ps. the reference https://www.nature.com/articles/2071084a0
"Published: 01 September 1965 The Bath-Tub Vortex in the Southern Hemisphere LLOYD M. TREFETHEN, R. W. BILGER, P. T. FINK, R. E. LUXTON & R. I. TANNER
pps. my earlier mention https://news.ycombinator.com/item?id=15122988 Nature volume 207, pages1084–1085(1965)"
AIUI the math is that the delta in acceleration across a 1m bathtub north-to-south would be 1x10-8 m/s/s due to Coriolis ... so your starting conditions would have to be at a level of perfection that I don't think anyone's achieved, certainly not some bloke in a drafty garage with a kiddy's wading pool one time.
I accept that in theory that delta definitely exists, but I don't accept that it can be, has ever been, observed at the tiny scales of a few metres, let alone the 100mm (toilet flushes) that's typically asserted by the faithful.
I accept that across dozens of kilometres we definitely do see this phenomenon as it generates consistent, hemisphere-dependent, large wind events (eg hurricanes) once you get a good way from the equator.
And searching for neutral questions like 'Why don't hurricanes form near the equator' reveals consistently Coriolis Effect explanations.
Wikipedia's article on subduction makes no mention of weather events at all.
Do you have any citations for your claim?
As an aside, the ITCZ is a trigger for hurricanes when it moves too far from the equator.
https://www.eoas.ubc.ca/courses/atsc113/sailing/met_concepts...
The Coriolis effect is WAY too weak to affect the direction the water is flowing. Typically the way the water moves initially and the shape of the container will have an outsized impact in the final direction.
Does it have an effect and can it sometimes be seen? Yes. Is it often swamped by other factors and rendered irrelevant? Also yes. That doesn't mean it's false, but it does mean that some statements that rely on it as a factual basis are at best mistaken.
It is something large enough to be plainly visible, but not something that appear on every drain.