Why does water make noise in an electric kettle?

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Did67
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by Did67 » 12/11/14, 19:04

Observe a resistance, and you will see that around, it "bubbles" very shortly after starting the kettle ... I was not talking about boiling, of course.

Now, in fact, bubbles or the Browian movement of molecules around resistance, there, the debate is open ... It may be molecular agitation before bubbles ...


But if you prefer chemical reactions, molecules that shatter, why not a nuclear mini-reaction, electromagnetic waves ... Or homeopathy ??? The memory of water that remembers that in another life, it had boiled ???

I leave you.

Just another experience: it turns out that I have slightly acidic water at my tap; no calciare, but pipes, heating resistors which corrode very slightly ... So my kettle is probably half a dozen, if not ten years without almost any deposit. But I certify that it makes noise when I set off. I therefore dismiss the idea of ​​limestone, based on this observation ...

If someone does the test with distilled water suggested by Malloche, we will see ...
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by Leydorn » 13/11/14, 10:51

Yes, serious confusion on my part, between noise as a signal (electromagnetic, like yesterday that emitted by Philae) and noise as sound, sound, acoustic, vibratory waves actually, emitted by the friction of grains of sand or any other movement offering resistance, this is a well-chosen example, because for pre-bubbles, simmering, they are also gas-liquid friction, in all cases the physical process is the same, it is the transformation state that creates this noise; for the bursting of a bubble it is the gas which escapes and remains gaseous certainly, as by deflating a balloon, frictions again and again, but in water, earth, fire, palsma , when a gas is formed, it creates two co-existing states, and the gas escapes from what holds it captive by emitting a sound.

Do you think that another approach is more relevant?
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by Did67 » 13/11/14, 11:14

Leydorn wrote:
between noise as a signal (electromagnetic, like yesterday that emitted by Philae)



For me, this is not a "noise". It is an electromagnetic wave that a receiver transforms into "noise", therefore a vibration of the air ...

As there is in your entourage a sacred mess of waves of all kinds (radio, GO / FM, etc ... TNT ... Wifi ... Bluetooth ...) that the adapted device transforms into vibration, by means of an "element" which vibrates and transmits these vibrations to the air (what is commonly called a "loudspeaker").

Moreover, more and more often, this "wave" becomes digital and there is no difference of a physical nature between the transmission of sound, image, text, video ... transmitted by coded channel, electromagnetic in this case (but it can also be via cable - ADSL - or light - optical fiber) ...

As I wrote above, I think they are vibrations, with "elements" that resonate. But to know if it is the micro-bubbles, or more generally, the vibration of the water molecules around the resistance, I admit not to comment ...
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by Did67 » 13/11/14, 11:18

On the off chance, I asked the question that arises here at Google. I should have started there!

Who answers me this:

http://www.larecherche.fr/savoirs/autre ... 2006-76012

Finally it is Jacques Leblond, professor emeritus at the Graduate School of Industrial Physics and Chemistry, Paris who responds, in the journal La Recherche [a peer-reviewed journal, which does not publish anything ...]
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by Obamot » 13/11/14, 16:38

Possible answer: good pick at the educational level.

On the other hand, relatively preliminary, therefore not brilliant on an epistemological level (without any offense, didactic question, it lacks the central role of the disciplinary contents of the two branches that the author is supposed to teach: et chemistry, since it lacks the opportunity to arouse curiosity about the permanent interaction between the laws of physics and those of chemistry: moreover where is chemistry in there? And what is the purpose of such an answer?). So everything depends on the idea that the "Reading committee"wanted to be heard and for which audience, right?

What does he actually say? He talks about the change of state of the water: liquid to gaseous, returning to liquid having regard to a temperature differential, then going back to gaseous, etc.: response already mentioned relatively better, notably by Maloche, and let us note, quite incomplete (which seems to have poorly satisfied the interlocutors of this thread it seems ...?)

In my humble opinion, the point is that it demonstrates "effects"the rise in temperature (then fall, then rise again, etc.), with interactions / telescoping at the level of"fluid dynamics"(in a way) is mainly linked to the change of state of the water (and already seen above ...): it tells us"how to(?)"this noise occurs but not exactly"Why(?)", at least not in enough depth. A more exhaustive answer has already been given above, and therefore confirmed by the correct reasoning of Maloche (and a few others) ...

Without wishing to prejudge, one wonders: answer fundamentally correct or for Boeotian?
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by Leydorn » 13/11/14, 17:38

There is simple common sense (the obvious) and elaborate common sense (requiring reasoning).

This question of bubbles, a baby understands it, it is simple common sense, obvious.

Strange that there are only university professors (or me) who understand it here.

You make things too complicated.

Fill a glass of water, take a straw, blow in it, listen.
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by Obamot » 13/11/14, 18:56

And is Leydorn telling us that? : Cheesy: : Mrgreen: Well here >>>

We simply had a relatively incomplete explanation (just read the previous posts to be convinced *). I say "relatively"because it is" good "pedagogically: I repeat!

By way of example, to explain how a reduced response can induce so many errors, just by explaining the same phenomenon "differently": today I had to pass the technical inspection of a vehicle. So I needed - a few days ago - to change the coolant when I noticed significant rust deposits in the expansion tank ...

So I rinsed the entire circuit at least five times and filled each time with oil exclusively from the fleet, then purged the air regularly, completing, until saturation, then drain filling, purging, draining etc.

Oddly enough, it bubbled with a lot of broth - relatively - at the start of the engine launch and the size of the bubbles decreased as the temperature rose, until it consisted only of a kind of foam (whereas with a kettle one would imagine the opposite ...: first small bubbles, etc.).

One can imagine that the foam came from residues left by the old antifreeze and that this was what explained a different behavior than with pure water in a kettle ... Well I don't know - such and how this physicochemical teacher did it in his explanation - how she could have brought some understanding to the observation of the phenomenon! **)

*)
When we deduce: the risk is to think "times"! (go to a false trail)
When we induce, not to think enough ...

**)
Because ... it could just as well have been deposits that the previous antifreeze - with antirust included - had detached and which had remained in suspension in the fluid! So all kinds of reactions could happen in there, until the circuit came to its point of equilibrium. So I suggest that a incomplete explanation would never have made it possible to understand this point of detail for lack of a general review of the problem or a deepening of the question ***).

But this is only my humble opinion.

***) Because a third element still appeared at the end and it was decisive, I had omitted to purge the air in the very small conduit which leads to the expansion tank to make it tight. To get to the bottom of it (and although no garage will do it for you, it was just an experience) so I took a funnel plugged into a flexible tube, filled it with fluid until the bubbles come out through the tank of the expansion tank thanks to gravity, and ...

... pffffuit more advantage of bubbles in the circuit, : Cheesy: just dilation ...!

;-)
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by Leydorn » 13/11/14, 19:39

Again, not only do you complicate a simple physical reaction, but you also bias it with details that are not only unnecessary, but superfluous.

Why?
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