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Comment by LeifCarrotson | Hacker News Reader

The answer to the click bait title: Because the lane length can vary by more than the time difference.

> In a 50 meter Olympic pool, at the current men’s world record 50m pace, a thousandth-of-a-second constitutes 2.39 millimeters of travel. FINA pool dimension regulations allow a tolerance of 3 centimeters in each lane ... Attempting to construct a concrete pool to any tighter a tolerance is nearly impossible; the effective length of a pool can change depending on the ambient temperature, the water temperature, and even whether or not there are people in the pool itself.

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This title is not click bait at all. It presents a question and spends a brief article explaining the exact answer to the question. The answer is too long to fit in the title, and there's no click every paragraph to get to the next one bullcrap.

So, build the pool slightly oversize, and have movable boards at one end that are laser-ranged to an accurate distance.

Sounds like something an engineer would say :)

Sure you can solve the problem. Is the solution worse than the problem? I think it might be here.

A few ties beat spending millions on Lazer walls.

The olympics cost ~$15 billion to host; an accurate range finding device costs a couple of hundred dollars. Heck, with a 3cm margin of error right now, even a $20 tape measure would be an improvement. I'm sure they can afford it :P

I think you missed the part about the pool expanding and contracting as the temperature changes.

Also, think about the false start measurement devices. Are those accurate to a a microsecond?

> expanding and contracting as the temperature changes.

So measure and adjust the adjustable end-plates a few minutes before each round starts? How rapidly can the temperature change? (I have no idea, but I'm struggling to imagine it changing a huge amount in a small amount of time)

> think about the false start measurement devices. Are those accurate to a a microsecond?

I have no idea, but I don't see why not. 10,000 FPS cameras are available on the general market already, so you could record each swimmer's start and adjust the timings as if they had all started at the same moment :)

There's probably more to setting up a sophisticated time-keeping operation than buying equipment.

I'm sure there is - I'd like to know what the real problems are, because I'm pretty certain that "we don't have the technology to accurately measure 50m" can't be the whole story :)

The have hard enough time just keeping the water not bright green.

If the presence or absence of people can affect the size, wouldn't the fact that swimmers start out of water and dive in screw this up?

Unless the boards were mechanized/able to adjust after the fact to maintain the correct distance despite changes to the pool environment. I was imagining setting up the boards prior to the race, but if they are responsive that's different.

Cool, problem solved. Can't wait to see this at the next Olympics!

The article is incredibly short and addresses what the title promises unbelievably succinctly.

While you called it clickbait, you quoted literally 35.7% of it (577 of its 1613 characters) to show your point, and what you left out was interesting history.

I think it's really rude of you to do this and use the word click bait.

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