Why does the kettle make noise before boiling? The electric kettle is very noisy, what should I do?
Every day, in hundreds of millions of kitchens around the world, water boils several times a day. And every person at least once in his life has asked the question: “why does there be noise before boiling?” Someone immediately remembers the school curriculum and the unusual word “cavitation” pops up in their memory.
“Some bubbles are bursting - that’s why there’s noise,” the subconscious helpfully prompts. But few people remember the exact course of the process. And, moreover, few people know that noise is created simultaneously by two phenomena.
What is boiling?
What is boiling? There is a clear definition: “Boiling is vaporization that occurs simultaneously throughout the entire volume of liquid.” To start the process, the following conditions must be met:
- Availability of steam generation centers;
- Constant heat supply;
When a liquid reaches a certain temperature, called its boiling point.
Why do steam bubbles form in boiling water?
The centers of vaporization around which bubbles begin to appear are small cracks, greasy spots, solid particles - dust particles. They trap small volumes of air, and the liquid traps the air until it begins to boil. Water also contains dissolved gases: oxygen, nitrogen, carbon dioxide. The bonds between gas molecules and water molecules are weak and quickly break down when heated. When the dissolved gas is released, the pressure of the water forces it to take on the most energy efficient shape - a spherical shape. You get bubbles.
After gas is released, high temperature begins to separate liquid molecules. Steam is formed, which is released into the already formed bubbles. This is how the boiling process begins.
Causes of noise when boiling
The first signs of boiling can be observed at the bottom of the kettle - there is the highest temperature, and this is where the first bubbles appear. Each of them contains gas and saturated steam. While the bubble is small, it is held in place by surface tension forces. Then fast-moving water molecules, which form steam, accumulate inside the bubble and it begins to expand. Separation occurs at the moment when the Archimedes force pushing out the bubble becomes greater than the tension forces holding it back. The bubble is released and rushes to the surface
The separation causes fluid vibrations. It is these vibrations that are the first cause of noise during boiling.. You can estimate the frequency of the resulting sound. It is inversely proportional to the time it takes for the bubble to rise from the bottom. Time characterizes the strength of the vibration caused by the separation.
Calculations have shown that the average lift-off time is about 0.01 seconds, which means the sound frequency is about 100 Hz. It was these data that allowed scientists to understand that there is some other reason for the noise when the kettle boils. After all, the real sound frequency was measured and turned out to be an order of magnitude higher than calculated.
The discovery of the dual nature of noise was made by Scottish scientist Joseph Black. This happened in the 18th century, during his work at the University of Edinburgh.
The main source of noise when water boils
It was Joseph Black who first investigated the boiling process and identified the source of the additional noise. He discovered that not all bubbles breaking away from the bottom and walls reach the surface. And at the very beginning of the boiling process, not a single bubble reaches the surface - they disappear in the water column.
The scientist was so interested in the phenomenon that he spent several sleepless nights trying to discover the reason for the disappearance of the bubbles. Research helped to draw the right conclusion. The answer turned out to be simple - temperature difference. At the beginning of their movement, the bubbles are in the hottest part of the vessel. The pressure of saturated vapor allows them to maintain a spherical shape.
Sound change when boiling water
As they move upward, the bubbles enter cooler layers. The steam begins to condense, the pressure inside drops. At some point it can no longer hold its shape and collapses. The phenomenon of formation, separation and collapse of bubbles during boiling was called “cavitation”. Were held necessary calculations, which showed that the sound frequency during collapse is close to 1000 Hz. The data correspond to the experimentally measured parameters. As the liquid heats up, the bubbles stop collapsing and the noise level changes. The sound frequency decreases noticeably. Soon, all the bubbles without exception reach the surface. The noise subsides and a “gurgling” occurs.
The birth, separation, ascent and bursting of bubbles is a physical phenomenon that millions of people see every day. But boiling is more complicated than it seems at first. Two processes can be distinguished: cavitation and liquid oscillation during bubble separation. Both produce a characteristic sound, but the acoustic effect of one is easy to distinguish from the other. You can easily determine by the noise when the water in the kettle has heated to the desired temperature.
Why does the kettle make noise when the water boils, and the closer to boiling, the louder, and when the water boils, much weaker? and got the best answer
Answer from Oriy Melikaev[guru]
The cause of any sound is mechanical vibrations of the medium. In a subcooled liquid, steam bubbles do form on a hot surface, but they do not rise to the surface. As the bubble grows, its “top” touches the colder liquid, the vapor condenses and the bubble collapses. That is, the bubble “breathes” all the time. This leads to fluctuations in the water in the kettle. This process continues until all the liquid has warmed up to the boiling point - the bubbles no longer collapse, but rise to the surface.
Reply from *Janelle*[guru]
Well, because... The water gurgles and boils, the molecules begin to move faster due to the high temperature, and that's why...
Reply from Philip petrov[guru]
It seems to me because before boiling, many small steam bubbles make noise, and by the time it boils they simply merge and large bubbles no longer make so much noise
Reply from Alexander Greshnev[guru]
Bubble boiling of water turns into film boiling.
Reply from Gena Vasilkovets[guru]
THERE ARE TWO ANSWERS:
1. Microorganisms begin to scream that they should not be cooked.
2. Steam bubbles, which form at the bottom of the kettle on microcracks or non-wettable droplets of fat, rise to the surface and eventually burst and all the steam accumulated in them comes to the surface. There are a lot of such bubbles, so the noise is loud. When the kettle boils, the bubbles become larger, but their number is smaller, and the noise weakens. In general, it’s better to find Ladsberg and read him. This seems to be volume 1.
Reply from Alex[newbie]
And if the water boils away, it will stop making noise altogether.
Reply from User deleted[master]
Noise is a mysterious and enigmatic thing!
Reply from Vladimir[guru]
The air is noisy. When water is heated, the solubility of gases in it is greatly reduced, and the main amount of dissolved air is removed at a temperature close to the boiling point. My statement is easy to verify: pour carbonated mineral water into a kettle and heat it - carbon dioxide Much more dissolves in water than air and the effect of noise when heating soda is very distinct.
Reply from Moby Dick[guru]
The noise that we hear when the kettle boils is, oddly enough, the sound of collapsing steam bubbles, which, rising upward, cool. When the water has already boiled, the collapse process stops, and the sound abruptly changes its character.
Reply from Cor48[guru]
Everything is correct about the collapse of steam bubbles, but the increase in sound is related to the size of these bubbles; the larger they are, the stronger the hydraulic shock when they collapse and, as a result, the louder the sound.
Reply from Olga Abramova[newbie]
the kettle is noisy, which is not good, as they said before, it doesn’t always make noise.
Reply from Irina Farrakhova[newbie]
The cause of any sound is mechanical vibrations of the medium. In a subcooled liquid, steam bubbles do form on a hot surface, but they do not rise to the surface. As the bubble grows, its “top” touches the colder liquid, the vapor condenses and the bubble collapses. That is, the bubble “breathes” all the time. This leads to fluctuations in the water in the kettle. This process continues until all the liquid has warmed up to the boiling point - the bubbles no longer collapse, but rise to the surface.
HOME » SOLUTION GUIDE
2014-05-31
Why does the kettle make more noise before it boils?
Solution:
Before boiling, steam bubbles begin to form in the hottest areas of the kettle, for example near the walls. However, as a result of contact with colder masses of water, the temperature of the walls of the bubbles may be insufficient to create atmospheric pressure. Therefore, the newly formed bubbles collapse, which causes a lot of noise.
Have you ever thought about what makes sounds when the kettle boils?
If you think carefully, you can guess.
Why does the kettle make noise when heating up?
The best thing to do is to immediately go and look into the kettle - we will see rising air bubbles, which at the end of their path burst and make a sound.
Where do these bubbles come from?
Let's say that we have an ordinary electric kettle, which heats water using a current that heats the spirals at the bottom of the kettle. Therefore, the temperature at the bottom of the kettle is very high, which is higher than at the top of the vessel. Because of this, bubbles form at the bottom, which are formed during boiling. After the water gets very hot, the bubbles separate from the bottom of the kettle and float to the top, where they shrink until they burst.
Later we don't hear the collapse because the temperature in the kettle is very high. The kettle is boiling, and we only hear gurgling, as these bubbles become very large from the heat and there are many more of them.
Perhaps, of course, this is due to the contact of hot with cold, and when the water gets very hot, the sound becomes less. But we still hear gurgling!
By the way, we must not forget that sounds attenuate in the volume of the room, and that our ear perceives low and high frequencies differently and because of this, the noise becomes less noticeable when heated.
In conclusion, I’ll say: “What difference does it make how it gurgles, the main thing is that the tea is delicious!”
Grade: 3
Uniqueness: 97 %
Date of publication: 30.03.2012 19:41
Faktrum warns: although this is very important to know, it is not taught in school. When water boils, its composition changes, which is completely normal: volatile components turn into steam and evaporate. Thus, boiled water is safe to drink.
But when the water boils again, everything changes for the worse:
Boiled water is completely devoid of taste. If you boil it several times, it becomes very, very tasteless. Some might argue that raw water also has no taste. Not at all. Do a little experiment.
At regular intervals, drink tap water, filtered water, boiled once and boiled many times. All of these liquids will taste different.
Life is in full swing
When you drink the latter version (boiled many times), you will be left with an unpleasant aftertaste in your mouth, some kind of metallic taste.
In addition, if you decide to re-boil the water, then pay attention to how much time has passed since the last boiling process. If enough has passed for a long time, then it is better to drain the water and fill the kettle with fresh water. The fact is that in stagnant water various harmful microorganisms, and more dust and other debris gets in.
So, some useful tips:
- For boiling, pour fresh water each time;
- do not boil the liquid again and do not add fresh liquid to its remains;
- Before boiling the water, let it stand for several hours so that heavy substances settle to the bottom;
- Having poured boiling water into a thermos (for preparing a medicinal mixture, for example), close it with a stopper after a few minutes, not immediately.
Read also: This is why we should start work or study no earlier than 10 am
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uForum.uz > THEMATIC FORUMS > Warm-up for the brain > Why is the kettle noisy
View full version: Why is the kettle noisy?
09.03.2011, 10:42
Alexander Sofyenkov
09.03.2011, 10:48
Why does a kettle of water make noise just before it boils and the noise suddenly subsides at the moment of boiling? What processes create this noise? Don’t ask me for the answer... I don’t know it, I can only guess.
At the heated bottom of the kettle, water turns into steam, bubbles with steam rise up. But before reaching the surface, the steam cools and the bubbles collapse.
Hence the noise.
The whole process can be seen in a glass teapot.
09.03.2011, 10:53
Alexander Sofyenkov
09.03.2011, 11:04
But before reaching the surface, the steam cools and the bubbles collapse. Hence the noise. So why the noise? They collapse, but they don’t burst. Moreover, they collapse as evenly as they appear. By the way, when heating water in a saucepan (without a lid), there is no such sound, but with your explanation the sound should not disappear.
Maybe the hydrodynamic and acoustic characteristics of the kettle have some effect :)
We need to watch
Evgeniy Sklyarevskiy
09.03.2011, 11:38
in a saucepan (without a lid) there is no such sound. So it’s all in the spout!
09.03.2011, 11:45
They collapse, but they don’t burst.
09.03.2011, 11:52
Clap your hands and think about where the noise is coming from. When I press my palms, there is no noise (this corresponds to the reverse absorption of steam into water), and if there is, it is from the escaping air escaping from the palms (and we have no escaping steam - the steam pressure is not lower than the water pressure on the walls of the bubble). So?
So it's all in the nose!
Why does the kettle make noise when you turn it on, then go silent, and then make noise until it boils?
Maybe... what makes the spout whistle when the water is not boiling, and what prevents the spout from whistling more when steam is pouring out during boiling? We need to observe. Observe. It seems that the process of vaporization is much simpler, but we really don’t know anything about it either.
09.03.2011, 13:02
So why the noise? They collapse, but they don’t burst. Moreover, they collapse as evenly as they appear.
During collapse, a short-term local change in pressure occurs - essentially the same sound wave. This is not the only example - for the same reason, when an incandescent lamp breaks, the ringing is accompanied by a clearly audible bang. The uniformity of the appearance and bursting of bubbles is relative - some time passes between the collapses, the duration of these intervals varies, but fits well within certain limits. The result is real “white noise”, the “voice” of chaos.
Clap your hands and think about where the noise is coming from.
What does the clap of one hand sound like?
09.03.2011, 16:15
This is not the only example - for the same reason, when an incandescent lamp breaks, the ringing is accompanied by a clearly audible bang. Anton. Here the situation is different. The steam collects in a bubble and turns back into water, sticking to more cold water. There is no excess pressure at all. The ball bursts/collapses absolutely evenly over a relatively long time, comparable to the lifetime of the bubble.
09.03.2011, 20:09
There is no excess pressure at all.
There is :) But it’s not excessive, but on the contrary – negative, since when the steam condenses, the bubble turns out to be empty. It collapses, hence the sound.
Alexander Sofyenkov
10.03.2011, 01:02
I found an interesting article about boiling water: http://www.t-z-n.ru/prehme/int_boiling.html
10.03.2011, 01:43
Only not excessive, but on the contrary - negative. So the process of dissolution of the bubble is continuous, where does a void without pressure suddenly form? That's the question.
11.03.2011, 13:51
Bubbles of steam travel from the hot bottom to the cold upper layers and become water, collapsing at high speed and producing sound waves. There will be noise both in the kettle and in the pan.
Moving to an area with more high pressure, the bubble cavitates and collapses, emitting a shock wave. “Cavitation” occurs as a result of a sharp decrease in pressure in the liquid. This is what destroys the surface of the pumps propellers, hydraulic turbines. Thanks to "cavitation" in washing machines It turns out to be a gentle wash and it’s more convenient to clean antiques..
11.03.2011, 14:45
Bubbles of steam travel from the hot bottom to the cold upper layers and become water, collapsing at high speed and forming sound waves. Is there confirmation? There will be noise both in the kettle and in the pan. Does the shurpa in your cauldron make noise before it boils?
11.03.2011, 14:48
Why does a kettle of water make noise just before it boils and the noise suddenly subsides at the moment of boiling?
And you sit down on the comforter yourself... I suppose it won’t work out in silence either.... 🙂
But seriously, the electric kettle is noisy too.
I think that this happens due to the heating of the coil (heating element) and the rapid heating of the water near it. In the case of gas, the metal on the sides of the kettle heats up, and droplets of steam and a film of water wetting the sides quickly evaporate (the effect is almost the same as if you drop water on a hot metal)….
i.e. this is the local boiling of small droplets of water. And when the water boils throughout the entire volume, it all evaporates evenly...
11.03.2011, 15:23
Such categorical arguments: Bubbles of steam travel from the hot bottom to the cold upper layers and become water, collapsing at high speed and forming sound waves. Is there confirmation? Mathematical model? There will be noise both in the kettle and in the saucepan. Is the shurpa in your cauldron noisy before boiling?
14.03.2011, 11:41
Who needs it? What's the question? Why is the kettle noisy? Is it necessary to model mathematically to explain why?
Try to confirm the following experiments:
1. Heat the kettle with different amounts of water: from 200 ml to 1.5 liters.
At the beginning of heating, the kettle does not make a sound for several seconds; then appears
and the noise increases, which, having reached its maximum, begins to subside and
replaced by the gurgle of boiling water.
The amount of water does not affect the intensity of the sound, but what more water,
the longer each of the noise periods (silence, increasing and
fading noise, gurgling).
2. The same thing, but with the lid open.
The nature of the noise change is the same (silence, increasing and
fading noise, gurgling), but: firstly, the noise became louder, secondly, while
With the same amount of water, the duration of the second stage increased.
The noise appears along with small bubbles on the heating element of the kettle, which,
Having come off the heating element, they do not reach the surface of the water, but “dissolve” in it.
3. Place a hollow object (glass
bottle).
The sound intensity will decrease, but the nature of the noise will not change.
4. Clamp the teapot between two wooden dies.
The result of the experiment coincides with the result of experiment No. 2.
Hypothesis 1.
When turned on, the heating element of the kettle
begins to intensively heat the lower layers of water, with
release of small steam bubbles. Steam bubbles
begin to rise and, coming into contact with not yet
heated mass of water, condense. As a result
instantaneous condensation occurs multiple “collapse” of small vapor bubbles,
which generates vibration of water and, as a consequence,
noise. The increase in noise at the beginning of the experiments is explained by
increase in the number of bubbles – adjacent to
Then the layer of water begins to warm up. Explanation
fading is that the temperature of the water in the kettle
The process of condensation of steam in water also increases
slows down and the water begins to boil.
Confirmation of this hypothesis:
The appearance of noise along with bubbles on the heating element of the kettle;
Reducing noise when heating water in a kettle;
Reducing noise when installed on an empty heating element glass bottle –
The area of contact between the heating element and water has decreased.
The kettle body cannot be considered a source of noise, because:
With the lid open, the kettle makes more noise, and the kettle clamped in a “vice”
no less noisy, i.e. The housing also serves for sound insulation.
The final confirmation of the hypothesis will be the heating of water, including
the same as a kettle, but with reduced power of the heating element.
Experiment with his heating element.
Conclusions:
The amount of water in the kettle affects the boiling speed: the more water,
the longer you wait for boiling;
A closed lid retains heat in the kettle and the water boils faster;
The kettle makes less noise if water is heated in it while it has not yet cooled down.
The water in the pan makes noise before it boils, but what about you? 🙂
14.03.2011, 18:59
The water in the pan is noisy before it boils, but what about you? I sometimes boil water in a cauldron and the cauldron does not make noise. And the kettle is noisy... even with the lid open :)
Evgeniy Sklyarevskiy
15.03.2011, 00:13
I sometimes boil water in a cauldron and the cauldron does not make noise. And the kettle makes noise... even with the lid open. What if you solder the spout to the cauldron? What are the forecasts?
15.03.2011, 08:58
What if you solder the spout to the cauldron? What are the forecasts? It won’t make noise... the question here is all about the temperature of the surface in contact with the water. For a cauldron it is lower, since the cast iron is thick, and for a tin pan it is higher, since the tin is thinner. I’m telling you, you can’t figure out bubbles without a mathematical model :)
15.03.2011, 14:03
For a cauldron it is lower, since the cast iron is thick, and for a tin pan it is higher, since the tin is thinner. But it seemed to me that the difference is in the surface area. The cast iron will still warm up, but the contact area of the cauldron is larger and “more voluminous” or something... accordingly, the liquid is heated over a larger volume, and the difference in temperature between the lower and upper layers of water is smaller.
15.03.2011, 14:30
and “more voluminous” or something... Maybe so. Due to the thick wall, the heat is better redistributed from the bottom to the edges... but then a large cauldron for pilaf should be “noisy”, but it doesn’t make noise either.
15.03.2011, 17:09
What is noise for you? How many db? 🙂
what happens if you boil the same water in a kettle in a vacuum?
28.03.2011, 11:40
what happens if you boil the same water in a kettle in a vacuum? I have a gas burner - it doesn’t burn in a vacuum.
Due to the absence of thoughts, something that is mistaken for wit gushes out.
Noise occurs under conditions of high water temperature gradient. This situation is typical in thin-walled and electric kettles, but not in a cauldron.
28.03.2011, 16:09
gushes out something that is taken for wit. Did they say something funny here?
Where? Noise occurs in conditions of high water temperature gradient. This situation is typical in thin-walled and electric kettles, but not in a cauldron. I agree with this, but it would have been better to clarify everything right away. For example, would sound appear in a thin-walled frying pan (wok, for example)? The answer is both yes and no, depending on other physical parameters. To produce sound before boiling, you need a combination of:
conclusion: not in every kettle and not always the water makes noise before boiling - this is not a matter of the shape of the spout, but of the amount of water and the design of the kettle. If, for example, you put a boiler in a ceramic teapot, then according to the resulting theory, the water should not make noise before boiling.
28.03.2011, 20:46
gushes out something that is taken for wit. Did they say something funny here? Where? Noise occurs in conditions of high water temperature gradient. This situation is typical in thin-walled and electric kettles, but not in a cauldron. I agree with this, but it would have been better to clarify everything right away. For example, would sound appear in a thin-walled frying pan (wok, for example)? The answer is both yes and no, depending on other physical parameters. To produce sound before boiling, you need a combination of:
1) thin and preferably flat bottom(for high heat transfer from the burner to the water);
2) a high wall of the vessel (and therefore a flat bottom), so that the water upper layers it was heated only by convection of warm water, but not from the walls - for this reason the cauldron is not suitable - heat transfer also comes from the walls of the cauldron and the sound does not appear.
3) A sufficient amount of water in the vessel so that the heating of the upper layers significantly lags behind the lower ones.
Those. conclusion: not in every kettle and not always the water makes noise before boiling - this is not a matter of the shape of the spout, but of the amount of water and the design of the kettle. If, for example, you put a boiler in a ceramic teapot, then according to the resulting theory, the water should not make noise before boiling.
It shouldn’t according to you, but it makes noise. Maybe it's cavitation?
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Today we’ll talk about electric kettles, or more precisely about the speculations and misconceptions associated with them.
You can write your opinion in the comments.
Myth 1. Water in a kettle becomes saturated with harmful substances during boiling.
This is only true for the lowest quality products. If the body of the electric kettle is made of high-quality material, there is no danger. The most environmentally friendly in this regard are glass and ceramics, which are inherently incapable of entering into chemical reactions. Moreover, contrary to popular belief, modern glass teapots very durable and resistant to damage.
But their metal counterparts are more reliable than ceramic and glass electric kettles. Metal products are more durable, and high-quality stainless steel also does not emit any harmful components when heated (note: by the way, there is now a lot of low-quality imported stainless steel on the cookware market - manufacturers and managers do not think about consumer health - see our articles about cookware. But this applies less to teapots, because in them, just water comes into contact with the stainless steel, and not an acidic environment, as in pans).
As for plastic models, theoretically, only safe food-grade plastic should be used for their production, the shelf life of which is about 3 years. In our opinion, metal and glass electric kettles are still preferable to plastic ones, because... plasticizers, although in small doses, gradually pass into the water.
Why electric Does the kettle start making noise as soon as scale appears in it?
And after these 3 years have passed, it is certainly better to replace the device with a new one. Available on store websites large assortment electric kettles different models, so if your product needs replacement, just stop by and select a new suitable device.
Myth 2 (this is not a myth, but the truth - editor's note). Electric kettles can cause fires
Modern kettles have a power of 2-2.5 kW and are designed for standard wiring; sometimes you can find 3 kW models, which can only be used if the wiring is in perfect condition. Usage last type products with insufficiently high-quality wiring can precisely cause short circuit. The only thing worth noting is that a short circuit due to poor-quality wiring can occur when using any electrical appliance - not just a kettle. In any case, you should be careful with electric kettles.
Myth 3. In electric kettles with a “gold-plated” spiral, scale does not form
The “gold” on the spiral of the product is titanium nitride. This compound is resistant to various chemicals and protects the spiral only from corrosion. Protection against scale is ensured by using purified or spring water, as well as purchasing kettles equipped with built-in filters. It is better not to buy kettles with a “gold-plated” spiral, since the “gilding” gradually passes into the water you consume, and there is nothing good about it.
Myth 4. An electric kettle cannot heat small amounts of water.
If the device has an auto-shut-off function when it boils and works without water, you can safely heat water for one cup. You just need to make sure that the liquid completely covers the heating element.
Myth 5. Electric kettles are suitable for heating soup and boiling milk
Who among the first users of electric kettles did not try to cook dumplings, sausages or heat soup in them? Remember the result? Do you also remember that the manual for any product says that nothing other than water should be placed in it, since food particles can stick to the heating element, and the expanded liquid can squeeze out the lid of the device? Likewise, you should not use carbonated water to descale your kettle. Our inquisitive minds found out long ago that the same “Coca-Cola” or “Sprite” contain orthophosphoric and citric acids, which dissolve plaque. However, along with them, there are also dyes and sweeteners that easily eat into the coating. heating element And inner part instrument housings.
