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On the Lighter Side => Science Experiments => Topic started by: hamdani yusuf on 16/03/2022 13:52:07

Title: How does microwave superheat water?
Post by: hamdani yusuf on 16/03/2022 13:52:07
I just found old raw videos I took while discussing in this thread.
https://www.thenakedscientists.com/forum/index.php?topic=78517

I guess it's time to edit and upload them, so the information that they contain becomes available to more people.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 24/03/2022 02:07:56
Here's my first video, not containing water yet, to demonstrate effects of high power microwave to conductors with different diameter and position.
The effect is similar to resistive heating.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 24/03/2022 09:02:28
Here's another video showing how to produce superheated water.
Unfortunately it doesn't provide explanation.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 24/03/2022 12:05:07
"How does microwave superheat water?"
The same way that anything else does.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 25/03/2022 02:39:34
"How does microwave superheat water?"
The same way that anything else does.
Is it the same way as infrared stove?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 25/03/2022 02:51:17
Here's another demonstration of superheated water explodes inside the microwave while being heated. The video was made by CrazyRussianHacker.

Preventing superheated water by microwave
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 25/03/2022 18:09:05
This isn't some weird magical phenomenon.
https://en.wikipedia.org/wiki/Bumping_(chemistry)


Is it the same way as infrared stove?
Do you know what
anything
means?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 26/03/2022 12:43:47
This isn't some weird magical phenomenon.
https://en.wikipedia.org/wiki/Bumping_(chemistry)


Is it the same way as infrared stove?
Do you know what
anything
means?

Here's what wikipedia says.
Quote
Bumping occurs when a liquid is heated or has its pressure reduced very rapidly, typically in smooth, clean glassware. The hardest part of bubble formation is the formation of the small bubble; once a bubble has formed, it can grow quickly. Because the liquid is typically above its boiling point, when the liquid finally starts to boil, a large vapor bubble is formed that pushes the liquid out of the test tube, typically at high speed. This rapid expulsion of boiling liquid poses a serious hazard to others and oneself in the lab. Furthermore, if a liquid is boiled and cooled back down, the chance of bumping increases on each subsequent boil, because each heating cycle progressively de-gasses the liquid, reducing the number of remaining nucleation sites.
The problem is the description there doesn't match with my experiments. First,  the superheating can be done slowly. The boiling/desuperheating process can also be done slowly. 
Title: Re: How does microwave superheat water?
Post by: Eternal Student on 26/03/2022 17:51:52
Hi.

Here's another demonstration of superheated water explodes inside the microwave while being heated.
    Please, please put some information in the text about the videos.
    For example, one of those videos seems to have been produced in Russia and seems to be a commercial business (the people who made the video may get paid per view by Google).   At the current time, a lot of sanctions have been put against Russia.   Even scientific endeavours that involved a collaboration (for example, the ExoMars mission carrying the Rosalind Franklin mars rover) have been put on indefinite hold.  It's not clear that a UK based forum website should be promoting those videos.
      However,  there's no rigorous restriction placed on the use of Russian resources that I know of at the moment.  It's just that I would always be grateful if someone using a video in their post can tell the audience something about it in the text - like the title, the creator or author and where the video is hosted (e.g. YouTube).   The users can make their own choice about whether they wish to follow that link.
- - - - - -
 
   These points about superheating in a microwave oven seem relevant.  I don't know, I'm not an expert on microwave ovens.

1.  Microwaves heat water rapidly.  There just isn't much time for bumping to happen or nucleation sites to form.   Other forms of heating, like putting a beaker of water into an oven fail to match this rate of heating.  There is much more time for the formation of a gas bubble, a nucleation site where further changes in phase can happen.

2.  Microwave ovens heat a small beaker of water quite evenly across the whole volume.  There isn't much of a convection current or turbulent flow in the fluid.  This also reduces the formation of nucleation sites.   The superheating effect is likely to be greatly reduced if a beam of microwaves was focused on only one corner of the beaker.

Best Wishes.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 26/03/2022 22:10:53
For example, one of those videos seems to have been produced in Russia and seems to be a commercial business (the people who made the video may get paid per view by Google).   At the current time, a lot of sanctions have been put against Russia.   Even scientific endeavours that involved a collaboration (for example, the ExoMars mission carrying the Rosalind Franklin mars rover) have been put on indefinite hold.  It's not clear that a UK based forum website should be promoting those videos.
AFAIK, playing a Youtube video from a third party site isn't count as a view. I tested it with my own video.  CMIIW.
Anyway, I can just add information in the description that the video was made by a Russian. But keep in mind that most Russians have nothing to do with the invasion. They just want to live their lives peacefully.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 26/03/2022 22:35:00
Microwaves heat water rapidly.  There just isn't much time for bumping to happen or nucleation sites to form.   Other forms of heating, like putting a beaker of water into an oven fail to match this rate of heating.  There is much more time for the formation of a gas bubble, a nucleation site where further changes in phase can happen.
As I said previously, rapidness doesn't seem to be the cause of superheating. It can be done slowly,  just like the desuperheating process, either by boiling using contact with conductive material, or just letting it slowly cool down to normal warm water.
The rapidness of heating depends on the quantity of water being heated, as well as the power of the microwave. The more water being heated, the slower the process becomes. But it can still be superheated.
In many cases, real world experiments can't be replaced by armchair thoughts, no matter how hard you think about it, especially when the underlying principle of the process is not widely understood, or there are some widespread misconceptions involved. That's why I made the investigation in the first place.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 26/03/2022 22:36:58
especially when the underlying principle of the process is not widely understood,
You may not understand it. That does not mean it is not understood.
That's why I made the investigation in the first place.

Did your investigations lead you to the explanation of why the liquid does not boil?
https://en.wikipedia.org/wiki/Laplace_pressure

Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 26/03/2022 22:56:09
I'm editing the next videos of my investigation on superheated water by microwave. If you are curious what they will show, just open the spoiler.
Spoiler: show

The first video shows my attempt to superheat my drinking water, which is a bottled mineral water. The result is that the water always boils and the intended superheating process can not occur.

The second video uses demineralized water.
But the microwave power is too much for the water, which makes it explode, so further investigation can't be done.

The third video shows the experiment in a more controlled manner.
It produces superheted water which can be desuperheated slowly.
Title: Re: How does microwave superheat water?
Post by: Eternal Student on 26/03/2022 22:56:34
Hi.

AFAIK, playing a Youtube video from a third party site isn't count as a view. I tested it with my own video.  CMIIW.

I'm not a YouTube or Google expert.  I also don't know how the nakedscientists website is setup.
However, there are several articles suggesting that YT views from a 3rd party website do still get counted.

   Do Embedded YouTube Videos Add to the View Count?
The short answer is, yes.
The long answer is a little more complicated.....   

[Taken fromhttps://www.alliedpixel.com/2019/09/do-embedded-youtube-videos-add-to-the-view-count/  ]

The things they go on to explain as being "complicated" include (but are not limited to) the following:   It might be that you (Hamdani) didn't watch for long enough or have already watched that video many times... these things can stop YT counting another view.
    The "number of views" counter at the bottom of a YT video is also only an approximation.  It's impossible to keep that number correct and updated in real time over a distributed service provision.   Specifically, you can be served that video from many different servers.  Sometimes you can come back to a YT video and the no. of views has apparently gone down - this is purely a consequence of being served the video from some other server.   
    The record of the number of views is updated in a complicated way, so that it is only correct eventually and if all views are stopped for a while so that every server catches up and reports its changes.  This avoids halting every server while just one server was editing the value of the variable (which is what you would have to do if there was a single value used by all servers).  More significantly, if one server crashed before it returned the new amended value to the pool of servers then no other server could serve the video because they don't have a correct value of the no. of views they can call up.

Best Wishes.
Title: Re: How does microwave superheat water?
Post by: Eternal Student on 27/03/2022 05:37:40
Hi again,

But keep in mind that most Russians have nothing to do with the invasion. They just want to live their lives peacefully.
   I'm well aware of that.  I'm saddened by the net effects of the current situation.  The situation with Russia was just one example of why it's helpful to have some text describing any video links.   I honestly don't know if we should stop watching Russian made YT videos at the moment, or if there's more good to come from continuing to co-operate and work with a common goal like developing science.  I just don't know - but the users should have the choice and should always be aware that some of those YT videos may be monetized.

  Anyway, I can see you've already done some editing on your earlier posts, thank you for that.

Best Wishes.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 27/03/2022 08:51:10
You may not understand it. That does not mean it is not understood.
If you think you already understand it, you should be able to describe my experimental results correctly.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 27/03/2022 08:52:44
Did your investigations lead you to the explanation of why the liquid does not boil?
https://en.wikipedia.org/wiki/Laplace_pressure
So far, no.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 27/03/2022 10:43:24
you should be able to describe my experimental results correctly.
I wasn't aware that you had done any experiments.
What did you do?
What happened?

Is there anything that wasn't explained by the conventional explanation?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 27/03/2022 14:55:28
you should be able to describe my experimental results correctly.
I wasn't aware that you had done any experiments.
What did you do?
What happened?

Is there anything that wasn't explained by the conventional explanation?
I haven't finished editing the videos. But I've provided a spoiler in case you have no patience to wait until tomorrow, or the day after tomorrow. It depends on my workload.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 28/03/2022 15:42:15
This video contains valuable information regarding commonly used commercial microwave oven. Although he only talks about microwave for 8 minutes, after which he goes back to focus on high power laser beam, which is his core business.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 28/03/2022 15:43:44
Here's my first attempt to superheat water using microwave oven. I used commercial bottled mineral water.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 28/03/2022 15:53:10
And here's another attempt. This time I used demineralized water.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 28/03/2022 22:46:52
Is there anything that wasn't explained by the conventional explanation?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 29/03/2022 02:28:16
Is there anything that wasn't explained by the conventional explanation?

What's the conventional explanation?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 29/03/2022 14:12:47
Is there anything that wasn't explained by the conventional explanation?

What's the conventional explanation?
Is this Wikipedia article considered a conventional explanation?
Quote
https://en.wikipedia.org/wiki/Superheated_water
Superheated water is liquid water under pressure at temperatures between the usual boiling point, 100 °C (212 °F) and the critical temperature, 374 °C (705 °F). It is also known as "subcritical water" or "pressurized hot water". Superheated water is stable because of overpressure that raises the boiling point, or by heating it in a sealed vessel with a headspace, where the liquid water is in equilibrium with vapour at the saturated vapor pressure. This is distinct from the use of the term superheating to refer to water at atmospheric pressure above its normal boiling point, which has not boiled due to a lack of nucleation sites (sometimes experienced by heating liquids in a microwave).
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 29/03/2022 15:34:15
Here's my next experiment
It's an attempt to superheat demineralized water in a styrofoam cup. The result shows whether smooth surface is required for superheating or not.

There are many more videos I've recorded as I've mentioned in another thread last year. I hope I can contribute to improve our understanding on this phenomenon.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 29/03/2022 20:08:25
Is this Wikipedia article considered a conventional explanation?
This bit is.
"This is distinct from the use of the term superheating to refer to water at atmospheric pressure above its normal boiling point, which has not boiled due to a lack of nucleation sites (sometimes experienced by heating liquids in a microwave)."

The explanation is " due to a lack of nucleation sites "
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 30/03/2022 03:11:51
Is this Wikipedia article considered a conventional explanation?
This bit is.
"This is distinct from the use of the term superheating to refer to water at atmospheric pressure above its normal boiling point, which has not boiled due to a lack of nucleation sites (sometimes experienced by heating liquids in a microwave)."

The explanation is " due to a lack of nucleation sites "

The question I want to answer is, "what makes good nucleation sites?".
In my video using demineralized water in a smooth glass, the water can still boil before I tested that it's also in superheated state.
My experiments also show that microwave water superheating is a different phenomenon from bumping, because it can be done slowly. The de-superheating process can also be done slowly and locally.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 30/03/2022 08:40:31
My experiments also show that microwave water superheating is a different phenomenon from bumping, because it can be done slowly.
Heating water slowly in a clean test tube with a flame can also cause bumping.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 30/03/2022 13:23:30
My experiments also show that microwave water superheating is a different phenomenon from bumping, because it can be done slowly.
Heating water slowly in a clean test tube with a flame can also cause bumping.


Have you tried to de-superheat the water by slowly dipping a metal object into it? What did you find?
Quote
https://en.wikipedia.org/wiki/Bumping_(chemistry)
Bumping is a phenomenon in chemistry where homogeneous liquids boiled in a test tube or other container will superheat and, upon nucleation, rapid boiling will expel the liquid from the container. In extreme cases, the container may be broken.[1]

Bumping occurs when a liquid is heated or has its pressure reduced very rapidly, typically in smooth, clean glassware. The hardest part of bubble formation is the formation of the small bubble; once a bubble has formed, it can grow quickly. Because the liquid is typically above its boiling point, when the liquid finally starts to boil, a large vapor bubble is formed that pushes the liquid out of the test tube, typically at high speed.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 01/04/2022 06:02:41
I've got an electric air heater which is useful to bend acrylic plates. The hot air can reach up to 300°C, which should be enough to boil demineralized water in a smooth glass, and bring it to superheated state, if the microwave is not necessary.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 01/04/2022 11:39:51
Have you tried to de-superheat the water by slowly dipping a metal object into it?
Of course I haven't.
I know that the best approach is to avoid superheating in the first place or, if you know that it has happened, you let it cool- undisturbed.

I've got an electric air heater which is useful to bend acrylic plates. The hot air can reach up to 300°C, which should be enough to boil demineralized water in a smooth glass, and bring it to superheated state, if the microwave is not necessary.
...
 or you could use a candle.

So what?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 02/04/2022 05:40:21
Of course I haven't.
I know that the best approach is to avoid superheating in the first place or, if you know that it has happened, you let it cool- undisturbed.
Then you have no evidence that it was superheated.
or you could use a candle.

So what?
ordinary candles are too small, hence it would be hard to overcome  radiation heat loss from the water surface and its container. Besides, the hot air is cleaner, so we don't have to worry about soot. 
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 02/04/2022 08:19:08
Meanwhile, I'm editing two videos investigating superheated water in microwave oven.

The first will show superheated water under a linear polarizer.
Spoiler: show

The de-superheating process seems more energetic than what's shown in previous experiment when the water was superheated without linear polarizer.


The second video will show superheated water in a glass bowl, which is meant as a larger smooth surface container.
Spoiler: show

It shows localized superheated water, where the water is superheated in one location, but not superheated just a few centimeters next to it.

Title: Re: How does microwave superheat water?
Post by: Bored chemist on 02/04/2022 11:34:41
Then you have no evidence that it was superheated.
In a laboratory context, you often have a thermometer...
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 02/04/2022 11:37:01
ordinary candles are too small,
I assure you that you can boil a test tube full of water with a candle flame.
The soot is the big problem.

The sort of alcohol burner used in chemistry sets would be a better option.

But that's beside the point.

It hardly matters how you heat the water.
Superheating is nothing to do with microwaves.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 02/04/2022 15:58:59
Then you have no evidence that it was superheated.
In a laboratory context, you often have a thermometer...

How do you know if the water has been superheated, by using only thermometer?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 02/04/2022 16:00:07
I assure you that you can boil a test tube full of water with a candle flame.
how big is the test tube?
how much is the water?
how big is the candle?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 02/04/2022 16:03:49
It hardly matters how you heat the water.
Superheating is nothing to do with microwaves.
My experimental results suggest otherwise.
I'll post them here soon after I finished uploading them.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 02/04/2022 17:13:06
It hardly matters how you heat the water.
Superheating is nothing to do with microwaves.
My experimental results suggest otherwise.
I'll post them here soon after I finished uploading them.
People were documenting superheating and supercooling before they knew about microwaves.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 02/04/2022 17:13:37
how big is the test tube?
Do you know what a test tube is?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 02/04/2022 22:42:30
People were documenting superheating and supercooling before they knew about microwaves.
Can you share the link?
A video would be better.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 02/04/2022 22:59:37
how big is the test tube?
Do you know what a test tube is?
Have you never worked with different sized test tubes?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 02/04/2022 23:06:45
how big is the test tube?
Do you know what a test tube is?
Have you never worked with different sized test tubes?
Yes, and they are all pretty close to the same size.
Do you know what a boiling tube is?
What about a micro tube?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 02/04/2022 23:07:40
People were documenting superheating and supercooling before they knew about microwaves.
Can you share the link?
A video would be better.
So... you want a video from before they had microwaves.
How many pre WWII video recorders do you think there were ?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 02/04/2022 23:13:16
https://en.wikipedia.org/wiki/Boiling_chip

Here's a reference from 1930.
https://archive.org/details/sim_journal-of-biological-chemistry_1930_88_contents/page/78/mode/2up?q=antibumping

Why don't you just accept reality?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 03/04/2022 03:29:23
Here's the video on superheating demineralized water in microwave oven under a linear polarizer.

Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 03/04/2022 03:33:22
Yes, and they are all pretty close to the same size.
Why do you expect everyone else to use the same size?
Do you know what a boiling tube is?
What about a micro tube?
Does it really matter what I know about them?
Can you just tell me?
Or Google them?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 03/04/2022 03:34:26
So... you want a video from before they had microwaves.
How many pre WWII video recorders do you think there were ?
Your own video would be enough. I bet you have a smartphone.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 03/04/2022 03:46:10
https://en.wikipedia.org/wiki/Boiling_chip

Here's a reference from 1930.
https://archive.org/details/sim_journal-of-biological-chemistry_1930_88_contents/page/78/mode/2up?q=antibumping

Why don't you just accept reality?
Some different phenomena may have similar symptoms. In this case, explosion of heated water inside a microwave oven may seem similar to bumping. But we need to consider other symptoms too, and compare if they are found in both cases.
That's why I asked you, who claimed to have experience with bumping. Did you find these symptoms?
Superheating and de-superheating can be done slowly.
Right after the explosion, the water can still be in superheated state.
The superheating is affected by linear polarization.
The superheating can be local and non-homogenous, which means some parts of the water can be superheated while some other parts are not.

Why don't you just enjoy the show?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 03/04/2022 10:33:41
The superheating is affected by linear polarization.
Interesting claim.
You don't have adequate evidence.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 03/04/2022 12:22:13
The superheating is affected by linear polarization.
Interesting claim.
You don't have adequate evidence.
I can repeat the experiments with and without linear polarizer, and measure the steam formed during desuperheating. If you have no patience waiting for my video, you can do it yourself. It doesn't require exotic equipments. Anyone can do that.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 03/04/2022 12:45:10
How are you polarising the microwaves?
Are you taking account of the fact that the magnetron produces a polarised beam?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 03/04/2022 14:18:02
How are you polarising the microwaves?
In case you haven't seen my video, it's done by placing a linear polarizer on top of the water container. If there's no other mechanism involved, we would expect to see less energy goes into the superheated water, instead of more.

Are you taking account of the fact that the magnetron produces a polarised beam?
Is it linearly polarized? What's the axis of polarization?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 03/04/2022 16:20:14
Is it linearly polarized? What's the axis of polarization?
I believe so and along the axis of the output coupling connector, I think.

But don't you think you should have checked that?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 03/04/2022 23:28:21
And here's what bumping looks like.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 03/04/2022 23:40:18
Is it linearly polarized? What's the axis of polarization?
I believe so and along the axis of the output coupling connector, I think.

But don't you think you should have checked that?

Perhaps you've also watched my other video on microwave transceiver with double reflector. Reflection can change polarization axis.
Inside the oven chamber, the microwave gets reflected multiple times. The rotation of the base also reduces polarization effect.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 04/04/2022 08:49:30
So, the effect you are looking for might be caused by the rotation of the dish?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 04/04/2022 12:56:12
So, the effect you are looking for might be caused by the rotation of the dish?
Both experiments involved rotation of the dish.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 04/04/2022 16:13:16
So both had variable polarisations.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 05/04/2022 09:42:39
So both had variable polarisations.
The polarizer was co-moving with the container, as well as the water. Thus, in the perspective of the water, the incoming microwave has constant polarization angle.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 06/04/2022 10:13:06
I've uploaded another video investigating superheated water by microwave oven. This time I used a larger container to show inhomogeneity of the superheated water.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 06/04/2022 10:59:45
So both had variable polarisations.
The polarizer was co-moving with the container, as well as the water. Thus, in the perspective of the water, the incoming microwave has constant polarization angle.
So the intensity would vary with time.
That's a troublesome confounding variable.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 06/04/2022 11:07:08
I've uploaded another video investigating superheated water by microwave oven. This time I used a larger container to show inhomogeneity of the superheated water.
The video shows little if any superheating.
Most of the bubbles are dissolved air.
Incidentally, a smooth metal object isn't a good nucleation source. You might want to try a wooden spoon.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 07/04/2022 15:37:26
How about demonstration of de-superheating while being superheated all at once? How much air can the water hold?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 07/04/2022 16:52:15
How much air can the water hold?
Not very much, but if the water is nearly boiling then any air bubbles are also expanded by the presence of water vapour.
The release of dissolved air is also limited by nucleation sites. That's the basis of the Mentos and cola demo.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 08/04/2022 06:04:01
How much air can the water hold?
Not very much, but if the water is nearly boiling then any air bubbles are also expanded by the presence of water vapour.
The release of dissolved air is also limited by nucleation sites. That's the basis of the Mentos and cola demo.

I repeated the heating for dozens of times with the same water, without the sign of reduced quantity of bubble in later tests. I don't think it came from the release of dissolved air.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 09/04/2022 04:51:53
Here's another video on bumping
Boiling without boiling chips

And this is Flash boiling superheated distilled water

Are they the same phenomenon?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 09/04/2022 05:03:03
Here's another interesting video
Adding sugar to superheated milk

Considering that commercial drinking water can not be superheated due to its impurity, it's surprising that milk can be superheated in this video. I'm not sure if it can be done for any kind of milk.

A Google search for milk substances gives me this.
Quote
THE CHEMISTRY OF MILK. The principal constituents of milk are water, fat, proteins, lactose (milk sugar) and minerals (salts). Milk also contains trace amounts of other substances such as pigments, enzymes, vitamins, phospholipids (substances with fatlike properties), and gases.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 11/04/2022 15:13:40
Here's my video showing desuperheating by a metal coin.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 11/04/2022 15:14:44
And this one shows superheating water with restricted direction of microwave.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 12/04/2022 17:35:07
Are they the same phenomenon?
In what way do you think they are (significantly) different?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 13/04/2022 22:23:32
Are they the same phenomenon?
In what way do you think they are (significantly) different?
Microwave superheated water can stay in superheated state longer when it's not induced to boil. It can last more than 30 seconds until it loses heat to surroundings.
How long can it last using other methods of heating?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 13/04/2022 23:18:23
How long can it last using other methods of heating?
Exactly the same as with microwaves.

How would it know the difference?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 14/04/2022 06:01:52
How long can it last using other methods of heating?
Exactly the same as with microwaves.

How would it know the difference?
I never see an experiment of superheated water that stays being superheated for long after the heating stopped. Just repeat my experiments, but use other heating methods instead of microwave oven.
I have tried to superheat demineralized water using infrared ceramic cooker. I used the same glass as my experiments with microwave oven. Unfortunately, the glass breaks down just before the water starts boiling.
Now I've got a borosilicate beaker which should be suitable for the experiment. Let's see what we'll get.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 14/04/2022 10:41:53
I never see an experiment of superheated water that stays being superheated for long after the heating stopped.
Did you look?

If there's no nucleation site, and no heat loss (i.e. an insulated container) then you can maintain a superheated liquid indefinitely.

https://en.wikipedia.org/wiki/Metastability#States_of_matter

 
Now I've got a borosilicate beaker which should be suitable for the experiment. Let's see what we'll get.
You will get the kind of behaviour that explains why people were using anti-bumping agents a hundred years ago (and longer than that , but they are harder to prove)
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 15/04/2022 05:59:07
Now I've got a borosilicate beaker which should be suitable for the experiment. Let's see what we'll get.
Now I've done recording the experiments. These are what I did.
1. Heat demineralized water in the borosilicate beaker in microwave oven until some bubbles are formed. Then test if it's superheated using a steel fork.
2. Reheat the water using microwave oven, and repeat the test.
3. Reheat the water using infrared ceramic stove until some bubbles are formed, and repeat the test.
4. Reheat the water using infrared ceramic stove until some bubbles are formed, and repeat the test.
5. Compare the results to determine if they are produced by the same phenomenon.

Is there any missing step I should have done?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 18/04/2022 13:39:20
Here are some other videos I took last year, but just finished editing.

Superheating Water With Linear Polarizer and Metal Basket

Plastic Button as Nucleation Site

Other Objects as Nucleation Site

De-superheating With Plastic Stick
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 18/04/2022 13:40:48
Now I've done recording the experiments. These are what I did.
1. Heat demineralized water in the borosilicate beaker in microwave oven until some bubbles are formed. Then test if it's superheated using a steel fork.
2. Reheat the water using microwave oven, and repeat the test.
3. Reheat the water using infrared ceramic stove until some bubbles are formed, and repeat the test.
4. Reheat the water using infrared ceramic stove until some bubbles are formed, and repeat the test.
5. Compare the results to determine if they are produced by the same phenomenon.
Now I've done editing and uploaded it.

Comparison with Infrared Stove
Title: Re: How does microwave superheat water?
Post by: alancalverd on 18/04/2022 14:16:14
Nucleation doesn't only require a foreign particle. Nucleation by movement is often observed when supercooled water freezes as frost on a car roof. Microwave absorption does not depend on convection so is less likely to invoke boiling nucleation as the water is heated relatively uniformly throughout its bulk or even top-down, unlike a conventional cooker.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 18/04/2022 14:39:12
Nucleation doesn't only require a foreign particle. Nucleation by movement is often observed when supercooled water freezes as frost on a car roof.
Is it foreign particle and movement, or
Is it foreign particle or movement,
Which is required for nucleation? Your statement is a bit ambiguous.


Microwave absorption does not depend on convection so is less likely to invoke boiling nucleation as the water is heated relatively uniformly throughout its bulk or even top-down, unlike a conventional cooker.
Standing wave in microwave oven produces non-uniform heating, that's why rotating base is provided in the first place.
Why infrared stove fails to produce superheated water?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 20/04/2022 11:53:56
At this point, is there anyone still doubt that there's a mechanism in superheated water by microwave which is not available in other heating methods?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 20/04/2022 13:10:41
there's a mechanism in superheated water by microwave which is not available in other heating methods?
You have not provided sufficient evidence to convince anyone of that claim.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 20/04/2022 17:37:03
there's a mechanism in superheated water by microwave which is not available in other heating methods?
You have not provided sufficient evidence to convince anyone of that claim.
Sufficiency of evidence can be different from one person to another. I'm pretty convinced by this experiment.
Now I've done recording the experiments. These are what I did.
1. Heat demineralized water in the borosilicate beaker in microwave oven until some bubbles are formed. Then test if it's superheated using a steel fork.
2. Reheat the water using microwave oven, and repeat the test.
3. Reheat the water using infrared ceramic stove until some bubbles are formed, and repeat the test.
4. Reheat the water using infrared ceramic stove until some bubbles are formed, and repeat the test.
5. Compare the results to determine if they are produced by the same phenomenon.
Now I've done editing and uploaded it.

Comparison with Infrared Stove

What kind of evidence is sufficient to convince you?
What's the evidence that you have against it?

Why infrared stove fails to produce superheated water?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 20/04/2022 19:40:43
What kind of evidence is sufficient to convince you?
Repeatable evidence.

Superheating is a hit-and-miss phenomenon.
Even in circumstances likely  to promote it, there's no guarantee it will happen.
So you failing to see it in one kitchen experiment is probably a coincidence.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/04/2022 02:49:46
Superheating is a hit-and-miss phenomenon.
No. I can produce it consistently using microwave, 10 out of 10 if needed.
What I need are demineralized water and smooth surfaced glass container.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 21/04/2022 08:50:24
Superheating is a hit-and-miss phenomenon.
No. I can produce it consistently using microwave, 10 out of 10 if needed.
What I need are demineralized water and smooth surfaced glass container.
Then why can't you produce it with an IR source?
Is it because you are only heating the bottom of the jug (The IR won't go through the glass) rather than the bulk of the water (as you do with microwaves)?

Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/04/2022 11:33:59
Superheating is a hit-and-miss phenomenon.
No. I can produce it consistently using microwave, 10 out of 10 if needed.
What I need are demineralized water and smooth surfaced glass container.
Then why can't you produce it with an IR source?
Is it because you are only heating the bottom of the jug (The IR won't go through the glass) rather than the bulk of the water (as you do with microwaves)?



Borosilicate transmits infrared light quite well.
(https://www.edmundoptics.com/globalassets/commerce/products/1002921.gif)

Water absorbs some infrared spectrum pretty well, although it's only a small portion of the spectrum.
(https://media.cheggcdn.com/media/938/93823c66-df4c-4e64-8c88-4d09dd446089/phpWvtoXU.png)
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 21/04/2022 13:35:21
OK, so. looking at the video, the IR hob seems to be glowing red hot.
It must be somewhere near 450C or 700K (I really don't have a better estimate than that.
And if we consider the emission spectrum from that, we can use something like this
https://www.spectralcalc.com/blackbody_calculator/blackbody.php
to calculate it
And we get a result like this
 [ Invalid Attachment ]

So we can see that practically none of the radiation is shorter than about 2 microns (where it would get through the glass jug).
And the peak is at about 4 microns- which is where your spectrum of borosilicate shows that it absorbs strongly.


And this is why I keep saying you should learn some science.
Title: Re: How does microwave superheat water?
Post by: alancalverd on 21/04/2022 17:40:13
At this point, is there anyone still doubt that there's a mechanism in superheated water by microwave which is not available in other heating methods?
No. What you have demonstrated is that microwave heating of very clean water in very clean glass may not have sufficient nucleation triggers to prevent superheating.

[quote ]Why infrared stove fails to produce superheated water?[/quote] Because the infrared stove heats the bottom of the container and thus generates much stronger convection currents than are present with microwave heating. Convection = movement = nucleation.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 22/04/2022 10:50:01
I find this site quite informative in explaining infrared stove. I used ceramic type.
https://turkish.ceramicx.com/information/teknik-destek/why-infrared/

(https://turkish.ceramicx.com/wp-content/uploads/sites/3/2019/09/about-infrared-018.png)

(https://turkish.ceramicx.com/wp-content/uploads/sites/3/2019/09/about-infrared-016.png)
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 22/04/2022 10:53:06
So we can see that practically none of the radiation is shorter than about 2 microns (where it would get through the glass jug).
And the peak is at about 4 microns- which is where your spectrum of borosilicate shows that it absorbs strongly.


And this is why I keep saying you should learn some science.
Do you think gas stove will give better result?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 22/04/2022 10:55:15
No. What you have demonstrated is that microwave heating of very clean water in very clean glass may not have sufficient nucleation triggers to prevent superheating.

Quote
Why infrared stove fails to produce superheated water? Because the infrared stove heats the bottom of the container and thus generates much stronger convection currents than are present with microwave heating. Convection = movement = nucleation.
Have you seen my videos, especially where superheating and de-superheating occur at once?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 22/04/2022 12:56:53
I find this site quite informative
Then, since that site tells you the IR from a ceramic heater is mainly near 3 to 10 microns, why did you say that borosilicate is transparent- even though you showed a spectrum which tells you it is opaque ?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 22/04/2022 22:56:46
I find this site quite informative
Then, since that site tells you the IR from a ceramic heater is mainly near 3 to 10 microns, why did you say that borosilicate is transparent- even though you showed a spectrum which tells you it is opaque ?
Transparency is not a binary value. Some of the infrared radiation can pass through the glass. Although it's not clear yet what happens to the rest of the spectrum. How much is reflected instead of absorbed?

There is a ceramic plate between the heat source and the beaker. The spectrum would be different than black body radiation

Do you think gas stove will give better result?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 23/04/2022 00:29:51
How much is reflected instead of absorbed?
And again...
Why do you refuse to learn science?

The answer is "not much" that's why I ignored it.
https://en.wikipedia.org/wiki/Fresnel_equations#Normal_incidence

Title: Re: How does microwave superheat water?
Post by: Bored chemist on 23/04/2022 00:32:39
The spectrum would be different than black body radiation
How different?

In particular...
https://en.wikipedia.org/wiki/Kirchhoff%27s_law_of_thermal_radiation

Again it would be helpful if you learned the science that was available a hundred years ago.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 23/04/2022 23:04:11
And again...
Why do you refuse to learn science?
You should answer it yourself.

The answer is "not much" that's why I ignored it.
https://en.wikipedia.org/wiki/Fresnel_equations#
Radiation from the left side of the heater comes with high incident angle before it reaches the right side of the beaker, and vice versa.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 23/04/2022 23:08:35
How different?
The ceramic plate filters out some wavelengths.

Again it would be helpful if you learned the science that was available a hundred years ago.
When was the microwave oven invented?

Do you think gas stove will give better result?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 24/04/2022 10:27:46
When was the microwave oven invented?
1955
On the other hand, Kirchhoff's radiation laws were published in 1860.
 
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 24/04/2022 10:30:37
The ceramic plate filters out some wavelengths.
By Kirchhoff's law, the ceramic plate does exactly as good a job of re-emitting those wavelengths as it does of absorbing them.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 24/04/2022 11:22:17
The ceramic plate filters out some wavelengths.
By Kirchhoff's law, the ceramic plate does exactly as good a job of re-emitting those wavelengths as it does of absorbing them.

The ceramic plate doesn't glow red. It's significantly cooler than the heating element.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 24/04/2022 11:25:04
Do you think gas stove will give better result?
It looks like I have to do the experiment myself, just as usual.
I've done recording the video, and I'll upload it after I finish the editing.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 24/04/2022 14:07:33
The ceramic plate filters out some wavelengths.
By Kirchhoff's law, the ceramic plate does exactly as good a job of re-emitting those wavelengths as it does of absorbing them.

The ceramic plate doesn't glow red. It's significantly cooler than the heating element.
So the fact that visible light  goes through borosilicate is even less relevant.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 25/04/2022 15:36:38
So the fact that visible light  goes through borosilicate is even less relevant.
The ceramic plate is somewhat transparent to red light, as shown in the video. So, the water receives some red and infrared radiation, beside the heat conduction from the borosilicate glass.
The difference from microwave oven is that the borosilicate glass generates almost no heat from the radiation. The heat is generated in the water instead.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 25/04/2022 16:33:27
So, the water receives some red and infrared radiation,
And the red light goes straight trough the water- because water is colourless.

What point are you trying to make?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 26/04/2022 03:45:59
So, the water receives some red and infrared radiation,
And the red light goes straight trough the water- because water is colourless.

What point are you trying to make?
Identify all differences and similarities between microwave oven and infrared stove in boiling demineralized water inside a smooth container. Then identify which differences contribute to the difference in their result regarding superheating of water.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 26/04/2022 08:06:18
So, the water receives some red and infrared radiation,
And the red light goes straight trough the water- because water is colourless.

What point are you trying to make?
Identify all differences and similarities between microwave oven and infrared stove in boiling demineralized water inside a smooth container. Then identify which differences contribute to the difference in their result regarding superheating of water.
OK the so called infrared stove does shine a small amount of red light through the water.
Do you think that is likely to have an effect?

What are the power ratings of the two systems?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 26/04/2022 12:32:34
OK the so called infrared stove does shine a small amount of red light through the water.
Do you think that is likely to have an effect?
A similarity between infrared stove and microwave oven : Some heat is generated in the water.
A difference: Most heat in boiling water by infrared stove is generated in the glass body, which is then transferred to water through conduction. Whereas most heat in boiling water by microwave oven is generated in the water itself.
Although it hasn't been obvious yet that the difference above is the one which causes the different result.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 04/05/2022 09:40:54

Here's the experiment of boiling demineralized water in borosilicate beaker using gas stove. It seems that lack of nucleation site can still make it boil. No superheating is shown.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 04/05/2022 13:19:12
At about 37 seconds you imply that my breath is at 100C on a cold day.

Your experiment shows that heating water from the bottom is less likely to cause superheating than if you heat it throughout.
So what?

In reality, superheating was documented long before anyone had microwave ovens.
So it is clearly possible to superheat water without using microwaves.

Do you accept that?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 05/05/2022 03:27:47
At about 37 seconds you imply that my breath is at 100C on a cold day.
How would you interpret the condensation there?

Your experiment shows that heating water from the bottom is less likely to cause superheating than if you heat it throughout.
So what?
The fire clearly touches the side of the beaker as well.

In reality, superheating was documented long before anyone had microwave ovens.
So it is clearly possible to superheat water without using microwaves.
What's your evidence? A video may be?
Do the superheated water by other means behave the same way as superheated water by microwave oven?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 15/12/2023 16:16:02
Here's another video trying to explain superheated water by microwave. It says that water can become hotter than its boiling point without actually boiling. Unfortunately, it's not demonstrated in the video, since the thermometer only show 208?F, instead of a number larger than 212?F.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 15/12/2023 23:00:39
I missed this at the time you posted it.
Quote from: Bored chemist on 04/05/2022 13:19:12
In reality, superheating was documented long before anyone had microwave ovens.
So it is clearly possible to superheat water without using microwaves.
What's your evidence?
Personal experience.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 16/12/2023 01:03:54
In all of the videos showing water bumping without microwave, the boiling happened while the water was being heated. Unlike those with microwave, where the boiling happened while the water was not being heated.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 16/12/2023 01:29:38
I missed this at the time you posted it.
Quote from: Bored chemist on 04/05/2022 13:19:12
In reality, superheating was documented long before anyone had microwave ovens.
So it is clearly possible to superheat water without using microwaves.
What's your evidence?
Personal experience.
What kind of heater did you use?
What's the container?

Why do you think my experiments using infrared and gas stove didn't produce superheated water?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 17/12/2023 00:24:34
Chemists (and others) have been putting effort into avoiding the problem of superheating water since, at least, when my dad's chemistry books were written.
https://en.wikipedia.org/wiki/Bumping_(chemistry)



Why do you think my experiments using infrared and gas stove didn't produce superheated water?
You need clean , smooth equipment.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 17/12/2023 04:23:04
Chemists (and others) have been putting effort into avoiding the problem of superheating water since, at least, when my dad's chemistry books were written.
https://en.wikipedia.org/wiki/Bumping_(chemistry)
Quote
Bumping occurs when a liquid is heated or has its pressure reduced very rapidly,
We can reliably produce superheated water using microwave even with a slow heating process. The superheated water can also be boiled slowly by immersing only a small amount of object.

It hints that they could be different/distinct phenomena.

You need clean , smooth equipment.
I used the same equipment for microwave as well as other kind of heaters, but the results are different.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 17/12/2023 16:44:17
Do water molecules carry watches?
If not, how do they know if they have been heated quickly?
If they don't know, then how can they act differently?

Title: Re: How does microwave superheat water?
Post by: Bored chemist on 17/12/2023 16:46:20
The explanation is " due to a lack of nucleation sites "
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 18/12/2023 13:24:08
Do water molecules carry watches?
If not, how do they know if they have been heated quickly?
If they don't know, then how can they act differently?


No. The experimenters are the ones with watches.
The rapid requirement is stated in the definition of bumping in the Wikipedia article. Consequently, if it's not rapid, it's not bumping.

The other difference between bumping and microwave superheating in my experience, is bumping occurs when the heating is still on going. On the other hand, in microwave superheating, the boiling can occur long after the heater is turned off, and the water is moved away from the microwave.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 18/12/2023 16:10:52
On the other hand, in microwave superheating, the boiling can occur long after the heater is turned off, and the water is moved away from the microwave.
I assure you that this happens with conventional heating too.

That's the reason for instructions like this
"The avoidance of ?bumping? can be achieved by the addition of pieces of broken pot or special anti-bumping
granules, which promote smooth boiling. Anti-bumping material should only be added to a cold liquid. If there is a
need to add it to a liquid that has already been heated, the liquid should be removed from the heat and allowed to
cool for several minutes, otherwise it may boil over.''
here
https://www.ase.org.uk/sites/default/files/chemistry%20PDFs/PDFs/Anti%20bumping%20granules.pdf
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 19/12/2023 08:36:55
The link says.
Quote
Anti-Bumping Granules
In Safeguards in the School Laboratory (11th edition), section 6.2 we state:
"The avoidance of ?bumping? can be achieved by the addition of pieces of broken pot or special anti-bumping
granules, which promote smooth boiling. Anti-bumping material should only be added to a cold liquid. If there is a
need to add it to a liquid that has already been heated, the liquid should be removed from the heat and allowed to
cool for several minutes, otherwise it may boil over.''
A letter received from a member provides a dramatic illustration of the necessity for this advice:
"During a class distillation of an ethanol/water mixture the teacher in charge realised that the pupils had not added
anti-bumping granules. He asked the pupils to stop heating and remove the bungs from the flasks. On adding
granules to two of the flasks violent boiling occurred and hot ethanol was thrown out, to a height of one metre or
more. The ethanol on the bench was then ignited by a bunsen burner ...... "
The obvious difference with my setup is the heated media. It uses ethanol/water mixture, while I used de-ionized water.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 19/12/2023 22:49:48
Did you think your post made sense?

Don't you understand what this means?

"Anti-bumping material should only be added to a cold liquid. If there is a
need to add it to a liquid that has already been heated, the liquid should be removed from the heat and allowed to
cool for several minutes, otherwise it may boil over.''

Where, in that warning, does it say it only apples to a mixture of alcohol and water?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/12/2023 03:01:38
Did you think your post made sense?

Don't you understand what this means?
Do you understand what my experimental results mean? I heated de-ionized water in a borosilicate beaker using microwave, infrared cooker, and gas stove. The microwave consistently produced superheated water. The other heater consistently produced normally boiling water. There must be at least one unidentified factor causing the difference.

Do you understand what understanding means?
Blindly accepting authoritative texts is not understanding.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 21/12/2023 12:30:41
Blindly accepting authoritative texts is not understanding.
Refusing to accept the testimony of someone who worked in a lab for 30 years or so is also "not understanding" reality.
I told you the observations and you asked for documentation. I provide documentation, and you say I shouldn't accept it.

Heating stuff in test tubes and flasks  over a Bunsen burner or hot plate or heating mantle has, over the centuries, produced superheating so reliably that people invented anti bumping granules  specifically to stop it.
The fact that you, on a few occasions, did not see it doesn't change that, does it?

There's nothing magic about microwaving stuff
The only big  difference is that the temperature gradients are typically less steep..
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/12/2023 13:03:06
Refusing to accept the testimony of someone who worked in a lab for 30 years or so is also "not understanding" reality.
Testimonies have lower scientific value than experimental results. Moreover, I don't know the details of your experience.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 21/12/2023 13:08:40
Testimonies have lower scientific value than experimental results.
You have just tried to tell us that the observations made by a scientist in a laboratory have less value than the observations made by a scientist in a laboratory.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 21/12/2023 13:09:22
I don't know the details of your experience.
That's OK, because I do.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/12/2023 13:42:30
I told you the observations and you asked for documentation. I provide documentation, and you say I shouldn't accept it.
Your documentation still can't answer my question, what caused the difference in my experimental results.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/12/2023 13:49:16
Testimonies have lower scientific value than experimental results.
You have just tried to tell us that the observations made by a scientist in a laboratory have less value than the observations made by a scientist in a laboratory.
How can I know that you didn't lie or being mistaken?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/12/2023 13:50:08
I don't know the details of your experience.
That's OK, because I do.
Why should I trust you?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/12/2023 14:13:57
The fact that you, on a few occasions, did not see it doesn't change that, does it?
What is the probability that ten out of ten trials giving the same results come from random events?
Let's say that my borosilicate beaker has too much imperfections that it can't produce superheated water by infrared nor gas stove. But microwave oven can still consistently produce superheated water. There must be something that caused the difference. Which so far hasn't been identified.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 21/12/2023 14:39:38
Testimonies have lower scientific value than experimental results.
You have just tried to tell us that the observations made by a scientist in a laboratory have less value than the observations made by a scientist in a laboratory.
How can I know that you didn't lie or being mistaken?
You can't.
But that's equally true whether I'm being a scientist or being a scientist.
Why would it be more trustworthy if I was a scientist rather than a scientist?

Your PoV makes no sense.
It's still me.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 21/12/2023 14:41:23
There must be something that caused the difference. Which so far hasn't been identified.
Here's a candidate.
What testing did you do to check it?
The only big  difference is that the temperature gradients are typically less steep..
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/12/2023 14:44:06
Here's another video trying to explain superheated water by microwave. It says that water can become hotter than its boiling point without actually boiling. Unfortunately, it's not demonstrated in the video, since the thermometer only show 208?F, instead of a number larger than 212?F.
Measuring the temperature of superheated water is challenging, since foreign material dipped in it can cause it to boil. Infrared thermometer has its own challenges, since it's affected by emmissivity of the surface.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/12/2023 14:48:42
Testimonies have lower scientific value than experimental results.
You have just tried to tell us that the observations made by a scientist in a laboratory have less value than the observations made by a scientist in a laboratory.
How can I know that you didn't lie or being mistaken?
You can't.
But that's equally true whether I'm being a scientist or being a scientist.
Why would it be more trustworthy if I was a scientist rather than a scientist?

Your PoV makes no sense.
It's still me.

You would be more trustworthy if I can replicate your experiment.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 21/12/2023 14:59:17
Countless observations of bumping have been recorded.
You can buy stuff to stop it.
https://apcpure.com/product/anti-bumping-granules/

If you can't replicate it, that's your screw up.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 21/12/2023 15:01:02
Infrared thermometer has its own challenges, since it's affected by emmissivity of the surface.
I have good news for you.
The emissivity of water near its boiling point is the same as the emissivity of water near its boiling point.
A more interesting problem is how far into the water does the thermometer "see"?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/12/2023 15:06:52
I just found this.

Quote
https://www.animations.physics.unsw.edu.au/jw/superheating.htm

Why does it occur to a greater degree in microwave ovens than in saucepans or kettles?
In a microwave oven, the water is usually hotter than the container, whereas parts of the kettle or saucepan are usually hotter than the water. Further, the surfaces of some containers used in microwave ovens may be very smooth, almost at a molecular scale, whereas this is not true for kettles or saucepans.
Microwave ovens heat the water directly: the microwaves pass through the container and the water, and the water itself absorbs energy from them. The container absorbs little energy directly. In a kettle or saucepan, the container itself (saucepan) or a heating element (some kettles) is hotter than the water. The hottest points cause a small amount of local superheating, boiling is initiated here, and this then stirs the water.
Just like any hypothesis, its veracity still needs to be verified.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/12/2023 15:09:45
Countless observations of bumping have been recorded.
You can buy stuff to stop it.
https://apcpure.com/product/anti-bumping-granules/

If you can't replicate it, that's your screw up.
Nevertheless, my setup can still consistently produced superheated water when microwave oven is used. Which was the reason why I tried to identify the difference in the first place.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 21/12/2023 15:16:09
Infrared thermometer has its own challenges, since it's affected by emmissivity of the surface.
I have good news for you.
The emissivity of water near its boiling point is the same as the emissivity of water near its boiling point.
A more interesting problem is how far into the water does the thermometer "see"?
What about at the center?

What's the highest temperature of superheated water have you ever measured?
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 21/12/2023 15:51:44
Just like any hypothesis, its veracity still needs to be verified.

What experiment would show it to be false?
Come back when you have tested it.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 22/12/2023 06:40:58
Quote
Microwave ovens used to heat food are not set to the frequency for optimal absorption by water. If they were, then the piece of food or liquid in question would absorb all microwave radiation in its outer layer, leading to a cool, unheated centre and a superheated surface. [4] Instead, the frequency selected allows energy to penetrate deeper into the heated food. The frequency of a household microwave oven is 2.45 GHz, while the frequency for optimal absorbency by water is around 10 GHz.
https://en.m.wikipedia.org/wiki/Dielectric_heating
 
Here's some info to consider in experiments using microwave oven.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 22/12/2023 06:46:28
Just like any hypothesis, its veracity still needs to be verified.

What experiment would show it to be false?
Come back when you have tested it.
If the container can be heated from the outside to be hotter than the water, and the water is still superheated.
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 03/03/2024 12:11:40
I just finished editing my old video using microwave oven to heat up a neon test lamp. It breaks down and burn in flame, and leaving some smoke. Instead of explanations, this short video asks some questions, like which part of the neon lamp absorbs microwave energy the most? What's the nature of the flame and smoke?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 04/03/2024 08:23:07
I just finished editing my old video using microwave oven to heat up a neon test lamp. It breaks down and burn in flame, and leaving some smoke. Instead of explanations, this short video asks some questions, like which part of the neon lamp absorbs microwave energy the most? What's the nature of the flame and smoke?

Here it is.

Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 04/03/2024 11:12:16
This video explore the danger from microwave oven for those who are curious, while still want to enjoy the safety behind a monitor.

I Tested the Limits of a Microwave
Quote
I'm still surprised how the experiments went at the end

Please note: This is for educational purposes, I don't encourage people to try this themselves
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 04/03/2024 19:10:49
I just finished editing my old video using microwave oven to heat up a neon test lamp. It breaks down and burn in flame, and leaving some smoke. Instead of explanations, this short video asks some questions, like which part of the neon lamp absorbs microwave energy the most? What's the nature of the flame and smoke?

Here it is.


can you post a picture of the neon lamp?
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 05/03/2024 01:31:12
can you post a picture of the neon lamp?
Just google it.
Title: Re: How does microwave superheat water?
Post by: Bored chemist on 07/03/2024 11:16:34
can you post a picture of the neon lamp?
Just google it.
I don't see how this was meant to help

https://en.wikipedia.org/wiki/It_(2017_film)


but that's what I got by googling "it".

This is what a neon lamp commonly looks like, but it's not what was in your video.
https://commons.wikimedia.org/wiki/File:Neon_lamp_NE-2.JPG

Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 07/03/2024 12:52:46
can you post a picture of the neon lamp?
Just google it.
I don't see how this was meant to help

https://en.wikipedia.org/wiki/It_(2017_film)


but that's what I got by googling "it".

This is what a neon lamp commonly looks like, but it's not what was in your video.
https://commons.wikimedia.org/wiki/File:Neon_lamp_NE-2.JPG



Neon lamp can take various shapes.
(https://upload.wikimedia.org/wikipedia/commons/thumb/b/b6/Socket_5.jpg/225px-Socket_5.jpg)

(https://upload.wikimedia.org/wikipedia/commons/thumb/5/5e/Neonlamp3.JPG/375px-Neonlamp3.JPG)
Quote
+DC (left), -DC (center), AC (right) supplied to NE-2 type neon lamps

Try searching for neon lamp tester.
(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQfWWvfvOb9G31Zxfe5RHSMwdk_1nr13_vz80LKrXIOiJQALsokB_X04ZHHR81aNLZrtzjP2fLWv3Xjne9OM2y4HpFnL_Td0aSJazwCp72J5N1Wz32QcGWNWgTpGJy2AhXBfZxWZOndw4a/w1280-h720-rw/Main-parts-of-neon-line-tester_Electrothinks.jpg)
(https://i0.wp.com/paktechpoint.com/wp-content/uploads/2023/09/image-418.png?fit=1236%2C1236&ssl=1)


Try searching for fuse type neon lamp.

(https://image.made-in-china.com/2f0j00dlCgkzjByhoO/Fuse-Type-Neon-Lamp-for-Power-Tester.webp)
(https://sc04.alicdn.com/kf/HTB1l1TVKFXXXXceXVXXq6xXFXXXY.jpg)
Title: Re: How does microwave superheat water?
Post by: hamdani yusuf on 08/03/2024 03:33:21
Quote
In this video I demonstrated how microwaves lose a great deal of their power, when you step away from the antenna source, In case you're wondering how far away I can get from my Lectenna, and light them up with my microwave, it was 37 feet.