What causes the sound of a dripping tap and how do you stop it? | Hacker News Reader

What causes the sound of a dripping tap and how do you stop it?

sciencedaily.com

55 pointsdaegloe36 comments

This is at least the second time that tap dripping was involved in a scientific study.

The first that I know of is when some Santa Cruz (hippie capital) students set up electronics to record the timing of drips for a paper. They were going to break the pattern down to understand it. They tried and tried but the pattern always seemed random.

With the help of other researchers they discovered it was caused by chaos. This was the first time that chaos theory was described, although Feynman had noticed that some equations behaved weirdly when banging on his calculator.

Interesting. Is this the paper?

https://doi.org/10.1016/0375-9601(85)90065-9

Yes. There's also this book:

http://www.worldcat.org/title/dripping-faucet-as-a-model-cha...

In fact, the interaction of water movements has good dynamical properties for liquid state machine (reservoir) computing [1] (purely as an interesting demonstration).

[1] "Pattern Recognition in a Bucket": https://link.springer.com/chapter/10.1007%2F978-3-540-39432-...

Chaos theory predates that, see https://en.wikipedia.org/wiki/Chaos_theory

One clever solution I've seen, if you can't fix it right away, is to tie a string from the spout and hang it down to the drain. The water runs along the string instead of falling and dripping.

I had a dripping pipe over my power shower pump and couldn't do anything immediately. So I taped a metal straw from the source of the drop angled down to a bowl. Worked perfectly.

This reminds me of a home I saw once with large rusty chains used as down spot channels from the rain gutters, it was pretty neat looking.

Rain chains are common in Japan, and decorative as well as useful.

https://en.wikipedia.org/wiki/Rain_chain

Just this week I was admiring one of these at Bogle Vinyards outside Sacramento.

Rain chains are pretty common if you might generate ice, too. Can help create an ice column instead of a mass that tears the gutter off.

Or you could wrap cling-foil around the tap. Saves water too :)

(I didn't test this)

I don’t think that would work. The pressure on the two sides of the leak will eventually equalize if the water can’t escape. Your cling wrap probably can’t contain that pressure. If you can’t turn the faucet on full blast and have the wrap stay, it won’t be able to contain the leak either.

Yeah, I thought of that. But I guessed that the foil would hold.

Yeah, a leaking pipe is essentially full pressure, just a low flow rate. It will only last until the void fills with water and then it will pressurize to the line's pressure.

According to my grandpa, who was a plumber his whole life, it's impossible to use tape to fix a leak.

My solution if I can't fix the leak is usually to place a sponge or cloth under the tap.

As long as we're asking plumbing noise questions, I'll ask one that I've never managed to find a satisfactory answer to.

When I turn on the hot water, such as in a tub or a sink, some cold water comes out before hot water does. (I have to wait for the water to "get hot", which of course is not really getting hot, it's flushing cold water out.) I'm pretty sure I'm not imagining this, but I can hear when the water is hot. The only way I know how to describe it is that it sounds a bit calmer. Why is that?

I saw a video about this recently: https://www.youtube.com/watch?v=Ri_4dDvcZeM

Thanks! I have literally wondered this since I was a kid, and this is the first satisfying explanation I've seen.

ITT people are so clever in creating a workaround but are unable to perform basic maintenance. Replacing washers is a fundamental skill

Just in case you didn't read the article, it makes no mention of the researchers' maintenance ability.

"According to the researchers, while the study was purely curiosity-driven, the results could be used to develop more efficient ways to measure rainfall or to develop a convincing synthesised sound for water droplets in gaming or movies, which has not yet been achieved."

Because of course everyone carries a stock of washers, in case of drips happening in the middle of the night.

And of course you can shut down the water to the faucet at a moments notice, without disturbing anyone.

And the replacements never fail, so it's perfectly fine to start such a project during non business hours, because you'll never have to keep the water off for hours or a weekend waiting for stores to open so you can get the parts you need.

And obviously everyone has time to do such a project the moment the drips start, because that's the highest priority.

> Because of course everyone carries a stock of washers

I was taught that you should always have a set in the toolbox...

> And of course you can shut down the water to the faucet at a moments notice

I was under the impression that even apartment/units have a separate water main valve to isolate the individual unit? My previous places did, although I more frequently rent houses.

> And the replacements never fail

They honestly rarely do fail when you put a fresh washer in.

> And obviously everyone has time to do such a project the moment the drips start

It honestly takes so little time to change a washer, I'm surprised that you've made such a long post about it, haha. A tap is a machine with one moving part... It's pretty straight forward and you can change a washer in like a minute.

Unless the bibb screw is rusted to nothing and you can't get it out. Or you got it out but you don't have a new one.

I've changed washers before, the things I posted are from experience not theory.

In my own experience, it is not an easy skill though. In the end it may look bad, behave bad (you bought wrong washer/materials/tools) or simply drip in another place, become greasy, leaky, squeaky, etc. It is an usual thing to outsource hard problems to professionals (and look at things as trivial when you’re one). I think that everyone should do what they really like to do and what they are satisfied with.

Stop using taps that need washers. All the taps in my house (in Norway) are over thirty years old and none of them drip. The reason is simply that they use a cartridge with ceramic mating surfaces.

I know of at least one of these ceramic valves that began leaking, but it was because of a gasket, not the ceramics.

https://youtu.be/6tddHSt6CUQ

> Stop using taps that need washers. All the taps in my house (in Norway) are over thirty years old and none of them drip. The reason is simply that they use a cartridge with ceramic mating surfaces.

Cartridges (ceramic or otherwise) fail for a variety of reason. Gaskets come in some fairly standard sizes and cost a few pennies to replace. Cartridges typically cost $20-$40 each, are quite non-standard even from a single manufacturer, and some manufacturers will require special tools to remove/install their cartridges. Plus a cartridge will still typically have gaskets that can fail (e.g. I recently had a diverter valve that was part of a cartridge leak and flood the under-sink area).

When I read the title, I thought it was /r/theonion

Put a dishrag under the drip-point, how difficult can it be? It will asorb all drip sounds. Let the drops fall onto a dish-rag.

The Cambridge University video linked to from the article with water drops being filmed “using high-speed cameras and high-sensitivity microphones”: https://www.youtube.com/watch?v=-iP3Dwy0RSQ

So a polyurethane mat with spikes pointing up to break the surface before impact would quiet it.

Like the fresheners in urinals have?

It's a bit disappointing that we need high speed cameras to figure this out. I would have expected simulations to be sufficient.

I think the 3D fluid dynamics simulation required to find this might be a much. I always figured "water droplets smashing into another surface" was sufficient. My dripping taps never seem to drip into a puddle of water, but on the sink surface. With the high-speed capture work from years ago on why droplets splash back from dry surfaces (because air), I'd have also assumed air would play a role in drops making noise when falling on water.

My point: I don't think we could have simulated this effectively; I think a thought experiment would suffice; but ultimately, high-speed would be a necessary step to observe what either experiment predicted.

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