Boiling point of water heated via microwave

[ScepticAmatuer]

What "truth"? Are you saying you think microwaves change the boiling point of water? What exactly do you think is going on that hasn't been adequately explained?

If microwaves can change a property as basic as surface tension, and that change persists even after the waves are shut off, then why not?

Or does that offend some scientific canon law or the other? So you appear the minute "censor" is mentioned?

In fact there is no general agreement about the mechanism of microwave action in accelerating (most) chemical reactions.

I look forward to the current canon law position on sonoluminescence and the electrohydraulic effect. More "bizarre" phenomenon not worthy of serious study, no doubt.

Why would anyone want to stifle debate on these topics? Hmmmm...

 

[OmCheeto]

I found a bunch of lug RTD's myself, but I'm becoming distracted. No idea the sparks that will fly when the microwaves hits those. And I am looking.forward to your response curve.

Fast!
98°C to 12°C in approximately 1 second.

A.microwave oven is a very powerful emitter of microwaves.

Well, I would hope so. How else am I to warm my coffee in the morning?

It should not be underestimated.

I've yet to estimate the power of my oven from my earlier graph.
I imagine that it's pretty close to nameplate.

Many factors besides intensity are at work.

Ummm...

If microwaves can change a property as basic as surface tension, and that change persists even after the waves are shut off, then why not?

Or does that offend some scientific canon law or the other? So you appear the minute "censor" is mentioned?

In fact there is no general agreement about the mechanism of microwave action in accelerating (most) chemical reactions.

I look forward to the current canon law position on sonoluminescence and the electrohydraulic effect. More "bizarre" phenomenon not worthy of serious study, no doubt.

Why would anyone want to stifle debate on these topics? Hmmmm...

The thread is still open.

Where is @Bandersnatch when you need him?

ps. Ok with me if you lock this thread. We seem to have deviated from experimentation into the whackadoodle universe.
pps. As always: Ok to delete, infract, and ban me. My thoughts are saved.

 

[ScepticAmatuer]

Fast!
98°C to 12°C in approximately 1 second.Well, I would hope so. How else am I to warm my coffee in the morning?

I've yet to estimate the power of my oven from my earlier graph.
I imagine that it's pretty close to nameplate.

Ummm...
The thread is still open.

Where is @Bandersnatch when you need him?

ps. Ok with me if you lock this thread. We seem to have deviated from experimentation into the whackadoodle universe.
pps. As always: Ok to delete, infract, and ban me. My thoughts are saved.

Ok. Thanks, man.

 

[OmCheeto]

Ok. Thanks, man.

You are quite welcome.

...
But no. My expt was the cooling curve and finding the start temp.
Interesting results and I agree about the "phase changey" bit at the start. Local condensation could have kept the temperature up at the start of the curve. but it seems not to start at 100. Is your thermometer ok?

I've been thinking about this some more, but have run into technical/safety concern issues.
I wanted to use a sealed container in the microwave, but am afraid if I heat it much above boiling, I might end up with a steam explosion, if I release the pressure too fast.
Also, the only device I have that is microwave-ably sealable would be a plastic coke bottle, and I'm not sure that would be safe.

Another idea is to seal the container after it comes out of the microwave, and draw a vacuum on the heated water until it boils again, and see how that affects the temperature drop. It would be quite the contraption though, as I'd have to monitor temperature and pressure inside the vessel. And without a vacuum pump, I don't know if I'd be able to get any meaningful data.

Today I attempted to double check the calibration of my RTD's using my new Infrared thermometer, but I couldn't get a stable reading. Perhaps tomorrow.

 

[ScepticAmatuer]

Here's the link to the full pdf of that article on surface tension. Surface tension affects vapor pressure which in turn affects boiling point, as you no doubt are aware.

http://www.researchgate.net/profile/Harisinh_Parmar/publication/264640617_Influence_of_Microwaves_on_the_Water_Surface_Tension/links/547c15370cf293e2da2d7919.pdf

IIts bibliography contains a plethora of interesting papers on microwave effects on "hydrogen bonding (unfortunately named).

Interesting that several of the articles/ research papers I've read claim that microwaves actually raise the boiling point of water to as much as 105°. (Standard conditions.)

They attribute this to-called non-thermal effects. Apparently, boiling points are not as sacrosanct as one would be led to believe by some postings in this thread.

I thank you for the opportunity to learn from you and contribute information of possible value.

 

[DrClaude]

Interesting that several of the articles/ research papers I've read claim that microwaves actually raise the boiling point of water to as much as 105°. (Standard conditions.)

They attribute this to-called non-thermal effects. Apparently, boiling points are not as sacrosanct as one would be led to believe by some postings in this thread.

You will have to post proper references for this claim.

 

[gjonesy]

I did a little snooping on the subject and found that a superheating temperature above 101 C have been documented. I could not find anything stating a specific temperature of 105 C that was documented. But the article did state that depending on the altitude that the temperature of pure water could continue to rise above 101 C. So a temp of 105 C doesn't seem implausible under perfect circumstances.

 

[ScepticAmatuer]

You will have to post proper references for this claim.

I don't recall you posting any references at all.

 

[berkeman]

Thread closed for Moderation...

 

[Doc Al]

I don't recall you posting any references at all.

You are the one claiming to have found some interesting information. So show your sources so we can learn! (And a link to "researchgate.net" is not a reliable source.)

Where were the papers published?

 

[berkeman]

Thread will remain closed until @ScepticAmatuer sends me a private message with acceptable sources (see the PF Rules under Info at the top of the page for the list of acceptable references).