[hamdani yusuf (OP)]

Here's my first attempt to superheat water using microwave oven. I used commercial bottled mineral water.

[hamdani yusuf (OP)]

And here's another attempt. This time I used demineralized water.

[Bored chemist]

Is there anything that wasn't explained by the conventional explanation?

[hamdani yusuf (OP)]

Is there anything that wasn't explained by the conventional explanation?

What's the conventional explanation?

[hamdani yusuf (OP)]

Is there anything that wasn't explained by the conventional explanation?

What's the conventional explanation?

Is this Wikipedia article considered a conventional explanation?

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).

[hamdani yusuf (OP)]

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.

[Bored chemist]

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 "

[hamdani yusuf (OP)]

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.

[Bored chemist]

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.

[hamdani yusuf (OP)]

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?

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.

[hamdani yusuf (OP)]

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.

[Bored chemist]

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?

[hamdani yusuf (OP)]

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. 

[hamdani yusuf (OP)]

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.

[Bored chemist]

Then you have no evidence that it was superheated.

In a laboratory context, you often have a thermometer...

[Bored chemist]

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.

[hamdani yusuf (OP)]

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?

[hamdani yusuf (OP)]

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?

[hamdani yusuf (OP)]

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.

[Bored chemist]

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.