Minutus

Not exactly.

Microwave heating is done due the dipole nature of whatever it heats. Water is strongly dipolar and fats and oils less so. It is the fact that we use alternating current, combined with the dipole nature of the material in the microwave oven, that allows dipolar substances to get hot. The electrical current causes the sipolar molecules to rotate, and then when the current changes direction the dipolar molecules have to also change direction and rotate the other way round. This contant movement against each other, and constant change of direction of movement of the dipolar subtances, causes them to get h ot. The eleectrical energy is converted to heat energy.

This is the same principle as when you convert rubbing action of rubbing your hands together, into heat energy - or if you speed it up and slide down a rope, the converted energy that becomes heat, causes rope burns.

So the food in a microwave is cooked by spinning dipole molecules fast enough with alternating current causing direction change, to convert the energy involved ito heat energy - much the way energy isconverrted to heat energy to warm your hands or get rope burns.
There is no "radiation" involved.

Electromagnetic waves have a specific frequency. Calling it radiation is just misleading.
We do not think of sunshine as radiation and we do not think of the light by which you are typing as radiation either.
All electromagnetic waves whether the light in your office, or microwaves, will go in all directions (ie will radiate - a verb, to radiate)
That does not make them "radiation" - a noun with different implications.
The term "electromagnetic radiation" is only correct when used to describe electromagnetic forces going in all directions - ie radiating in all directions.
So microwaves radiate. They are not radiation.

Namaste,
Irene
--
Irene de Villiers, B.Sc AASCA MCSSA D.I.Hom/D.Vet.Hom.
P.O. Box 4703 Spokane WA 99220.
www.Furryboots.info
(Info on Feline health, genetics, nutrition & homeopathy)
"Man who say it cannot be done should not interrupt one doing it."

I am sure that when the hysterians use the word "radiation", they unconsciously are referring to ionizing electromagnetic waves (and/or ionizing elementary particles). All of the ionizing electromagnetic waves lie above visible light, from ultra-violet all of the way up to and including gamma rays and beyond, if there is anything beyond. The shorter the wavelength, the higher the frequency, the more the energy and the more potentially damaging it is.

Anything below visible light, from infra-red to AM radio and below, is not ionizing and is basically harmless, unless of course you get too much, as in too much heat. Infra-red is what we call radiative heat, and microwaves are even below that, less energetic.

Soroush is right that it is all radiation, but some radiation is harmful even in small amounts. The higher the frequency, the shorter the wavelength, the more energetic, the more damaging. Obviously, anything that is less energetic than visual light cannot be damaging in the sense of ionizing radiation. Ionizing means that the waves can whack electrons out of their orbits and worse, perhaps even tear apart nuclei.

The bottom line is that microwaves are even less ionizing and therefore less "radioactive" than heat/infra-red and visual light.

The thing with heat is that you feel it easily and immediately and you react accordingly. But microwaves are not felt and they penetrate. In the old days, some microwave ovens may have leaked. This was bad because some people who stood close to the microwave ovens could be getting hit by the waves and not realize it. Fortunately, I never heard of a real live case where this happened. Of course, that doesn't stop the hysterians from worrying about it and getting in the way of my conveniences.
Roger Bird
________________________________

To: minutus@yahoogroups.com
From: minutus@yahoogroups.com
Date: Sun, 8 Mar 2015 19:57:44 -0500
Subject: Re: [Minutus] Microwaving water

Thanks, Soroush!
I too was wanting to point out that this term "radiation" certainly applies to microwaves -- just as it applies to light, radio waves, and the rest of the "electromagnetic spectrum", as well as to e.g. gamma waves and the other "nasties" from e.g. nuclear radiation.

I'm guessing that Irene's point is that microwave radiation does *not* make anything "radioactive" (it does not leave any radiation behind in its wake), which is certainly an important point of confusion for some.
I find this definition:

ra·di·a·tion
ˌrādēˈāSH(ə)n/
noun

1.
Maybe that clarifies the confusion a little?
Shannon
________________________________

Irene, how do you define "radiation"?

Please see how CERN describe the process.

http://scitech.web.cern.ch/scitech/TopT ... ve_2.shtml
Microwave ovens use radio waves at a specifically set frequency to agitate water molecules in food. As these water molecules get increasingly agitated they begin to vibrate at the atomic level and generate heat. This heat is what actually cooks food in the oven. Because all particles in the food are vibrating and generating heat at the same time, food cooked in the microwave cooks much more swiftly than food cooked in a conventional oven where heat must slowly travel from the outside surface of the food inward.
You seem to be confusing the action of microwaves with that induction heating alternative currents.

In induction heating, by the fact that alternative current is used, iron structures change directions rapid and thus cause heat. Hence the pan gets hot and not the cooker!
With microwaves, you make the water molecules, present in most things excited and vibrate rapidly.
Rgds

Soroush
From: minutus@yahoogroups.com [mailto:minutus@yahoogroups.com]
Sent: 09 March 2015 07:34
To: minutus@yahoogroups.com
Subject: Re: [Minutus] Microwaving water
Microwaves with certain wavelengths are absorbed by water molecules making them vibrate fast and thus cause heat and so can be used for cooking. Water in the food absorbs the microwave radiation, which causes the water to heat up and cook the food and this is also used in various industrial processes too.
Not exactly.
Microwave heating is done due the dipole nature of whatever it heats. Water is strongly dipolar and fats and oils less so. It is the fact that we use alternating current, combined with the dipole nature of the material in the microwave oven, that allows dipolar substances to get hot. The electrical current causes the sipolar molecules to rotate, and then when the current changes direction the dipolar molecules have to also change direction and rotate the other way round. This contant movement against each other, and constant change of direction of movement of the dipolar subtances, causes them to get h ot. The eleectrical energy is converted to heat energy.
This is the same principle as when you convert rubbing action of rubbing your hands together, into heat energy - or if you speed it up and slide down a rope, the converted energy that becomes heat, causes rope burns.
So the food in a microwave is cooked by spinning dipole molecules fast enough with alternating current causing direction change, to convert the energy involved ito heat energy - much the way energy isconverrted to heat energy to warm your hands or get rope burns.

There is no "radiation" involved.
Electromagnetic waves have a specific frequency. Calling it radiation is just misleading.

We do not think of sunshine as radiation and we do not think of the light by which you are typing as radiation either.

All electromagnetic waves whether the light in your office, or microwaves, will go in all directions (ie will radiate - a verb, to radiate)

That does not make them "radiation" - a noun with different implications.

The term "electromagnetic radiation" is only correct when used to describe electromagnetic forces going in all directions - ie radiating in all directions.

So microwaves radiate. They are not radiation.
Namaste,

Irene

--

Irene de Villiers, B.Sc AASCA MCSSA D.I.Hom/D.Vet.Hom.
P.O. Box 4703 Spokane WA 99220.
www.Furryboots.info

(Info on Feline health, genetics, nutrition & homeopathy)
"Man who say it cannot be done should not interrupt one doing it."

Beautifully written, but best of all is your term
hysterians...love that!


Irene
________________________________
________________________________

When used alone it implies ionizing radiation.
When used within a phrase such as heat radiation, light radiation, microwave radiation. etc it refers to where there is an effect rather than what effect there is.
Heat radiation - heat in all directions
Microwave radiation - microwaves in all directions.

...Irene

--
Irene de Villiers, B.Sc AASCA MCSSA D.I.Hom/D.Vet.Hom.
P.O. Box 4703 Spokane WA 99220.
www.Furryboots.info
(Info on Feline health, genetics, nutrition & homeopathy)
"Man who say it cannot be done should not interrupt one doing it."

Prove it?

It matters HOW they get "agitated" Soroush.
If your story here was true you could use direct current to make a miocrowave work. But that is not possible.
It is the alternating current that is involved in what you call "agitation" of the DIPOLAR molecules. it only works with molecules which have two electrically different poles.
That is not only water, but also oils and fats and other molecules. Hence you can heat and melt butter or coconut oil in the microwave, which also would not work if your theory about only water being hesated was valid.

Induction cooking uses an oscillating magnetic field (triggered by alternating current) to transfer heat.
Any oscillating magnetic field causes a magnetic flux (flux = flow) much like the technology used in a transformer, where proximity of windings is all that is needed, no actual touching, to transfer magnetic energy.
The metallic cookware gets in the way of the magnetic flow/flux by providing a resistance to this magnetic flux and the ineffieicnt flow of magnetic energy - the resistance in the metal - is expressed as heat in the metal. ie induced heat = induction cooking.
(Compare witih induction motors in electrical work. Induction cooking uses the induction principle plus the resistance one.)

Namaste,
Irene

Dear Irene

Does your washing machine, dishwasher or indeed any appliance that you have in the house work with direct current?

No! - Why? Because alternative current is more efficient.
So the fact that the microwave oven works on alternative current is totally irrelevant. For example change the frequency setting of the microwave (as used in communication) and the water molecules no longer get agitated!

And the fact that you can get an effect from the microwaves at a distance from its generator, means that it is the effect of the microwaves produced and not the type and frequency of the electricity powering the system.

Look at it another way - a radio generator and receiver can be battery or mains (alternative current) powered.

What you find is that often there are circuits that convert the alternative current into direct current for it to work.

So the type of electricity coming through has nothing to do with the out put of various piece of equipment provided that the equipment has been designed to run with that type of out put.
As mentioned before, domestic induction cooking hobs use alternative currents as their input, but at much higher frequency than the 50 or 60 Hz used in US or Europe and usually in the range of 20-100 kHz to produce the rapid electromagnetic changes needed. Ditto for industrial induction heaters where you can heat to white hot a billet of iron or steel weighing 100 kg in a matter of seconds.
If you look at the design of the circuit of a microwave system, you will see that firstly it used very high voltage (via a transformer) and then a capacitor to produce direct current as the system works on a cathode and an anode (which means that the system actually works on direct current.)

From http://en.wikipedia.org/wiki/Cavity_magnetron

"The magnetic field is set to a value well below the critical, so the electrons follow arcing paths towards the anode. When they strike the anode, they cause it to become negatively charged in that region. As this process is random, some areas will become more or less charged than the areas around them. The anode is constructed of a highly conductive material, almost always copper, so these differences in voltage cause currents to appear to even them out. Since the current has to flow around the outside of the cavity, this process takes time. During that time additional electrons will avoid the hot spots and be deposited further along the anode, as the additional current flowing around it arrives too. This causes an oscillating current to form as the current tries to equalize one spot then another.[9]

The oscillating currents flowing around the cavities, and their effect on the electron flow within the tube, causes large amounts of microwaves to be created in the cavities. The cavities are open on one end, so the entire mechanism forms a single larger microwave oscillator. A "tap", normally a wire formed into a loop, extracts microwave energy from one of the cavities. In some systems the tap wire is replaced by an open hole, which allows the microwaves to flow into a waveguide ."
To sum up, it is the action of the microwaves at a narrow range of frequencies that agitates/rotates the polarised molecules (mainly of water) and thus produce heat the input electrical frequency is irrelevant.
Rgds

Soroush
From: minutus@yahoogroups.com [mailto:minutus@yahoogroups.com]
Sent: 09 March 2015 22:25
To: minutus@yahoogroups.com
Subject: Re: [Minutus] Microwaving water
Please see how CERN describe the process.

http://scitech.web.cern.ch/scitech/TopT ... ve_2.shtml
Microwave ovens use radio waves at a specifically set frequency to agitate water molecules in food.
Prove it?
It matters HOW they get "agitated" Soroush.

If your story here was true you could use direct current to make a miocrowave work. But that is not possible.

It is the alternating current that is involved in what you call "agitation" of the DIPOLAR molecules. it only works with molecules which have two electrically different poles.

That is not only water, but also oils and fats and other molecules. Hence you can heat and melt butter or coconut oil in the microwave, which also would not work if your theory about only water being hesated was valid.
Induction cooking uses an oscillating magnetic field (triggered by alternating current) to transfer heat.

Any oscillating magnetic field causes a magnetic flux (flux = flow) much like the technology used in a transformer, where proximity of windings is all that is needed, no actual touching, to transfer magnetic energy.

The metallic cookware gets in the way of the magnetic flow/flux by providing a resistance to this magnetic flux and the ineffieicnt flow of magnetic energy - the resistance in the metal - is expressed as heat in the metal. ie induced heat = induction cooking.

(Compare witih induction motors in electrical work. Induction cooking uses the induction principle plus the resistance one.)
Namaste,

Irene
As these water molecules get increasingly agitated they begin to vibrate at the atomic level and generate heat. This heat is what actually cooks food in the oven. Because all particles in the food are vibrating and generating heat at the same time, food cooked in the microwave cooks much more swiftly than food cooked in a conventional oven where heat must slowly travel from the outside surface of the food inward.
You seem to be confusing the action of microwaves with that induction heating alternative currents.

In induction heating, by the fact that alternative current is used, iron structures change directions rapid and thus cause heat. Hence the pan gets hot and not the cooker!
With microwaves, you make the water molecules, present in most things excited and vibrate rapidly.
Rgds

Soroush
From: minutus@yahoogroups.com [mailto:minutus@yahoogroups.com]
Sent: 09 March 2015 07:34
To: minutus@yahoogroups.com
Subject: Re: [Minutus] Microwaving water
Microwaves with certain wavelengths are absorbed by water molecules making them vibrate fast and thus cause heat and so can be used for cooking. Water in the food absorbs the microwave radiation, which causes the water to heat up and cook the food and this is also used in various industrial processes too.
Not exactly.
Microwave heating is done due the dipole nature of whatever it heats. Water is strongly dipolar and fats and oils less so. It is the fact that we use alternating current, combined with the dipole nature of the material in the microwave oven, that allows dipolar substances to get hot. The electrical current causes the sipolar molecules to rotate, and then when the current changes direction the dipolar molecules have to also change direction and rotate the other way round. This contant movement against each other, and constant change of direction of movement of the dipolar subtances, causes them to get h ot. The eleectrical energy is converted to heat energy.
This is the same principle as when you convert rubbing action of rubbing your hands together, into heat energy - or if you speed it up and slide down a rope, the converted energy that becomes heat, causes rope burns.
So the food in a microwave is cooked by spinning dipole molecules fast enough with alternating current causing direction change, to convert the energy involved ito heat energy - much the way energy isconverrted to heat energy to warm your hands or get rope burns.

There is no "radiation" involved.
Electromagnetic waves have a specific frequency. Calling it radiation is just misleading.

We do not think of sunshine as radiation and we do not think of the light by which you are typing as radiation either.

All electromagnetic waves whether the light in your office, or microwaves, will go in all directions (ie will radiate - a verb, to radiate)

That does not make them "radiation" - a noun with different implications.

The term "electromagnetic radiation" is only correct when used to describe electromagnetic forces going in all directions - ie radiating in all directions.

So microwaves radiate. They are not radiation.
Namaste,

Irene

--

Irene de Villiers, B.Sc AASCA MCSSA D.I.Hom/D.Vet.Hom.
P.O. Box 4703 Spokane WA 99220.
www.Furryboots.info

(Info on Feline health, genetics, nutrition & homeopathy)
"Man who say it cannot be done should not interrupt one doing it."
--

Irene de Villiers, B.Sc AASCA MCSSA D.I.Hom/D.Vet.Hom.
P.O. Box 4703 Spokane WA 99220.
www.Furryboots.info

(Info on Feline health, genetics, nutrition & homeopathy)
"Man who say it cannot be done should not interrupt one doing it."

I think that Soroush and Irene are saying the same thing. Remember that light is both a particle and a wave at that level and smaller, so that at that level we can easily trip over semantics. I think that Soroush is saying that the atoms get agitated, and Irene is saying that the atoms switch direction because of the very temporary change in polarity. I don't see the difference.

Roger Bird
________________________________

To: minutus@yahoogroups.com
From: minutus@yahoogroups.com
Date: Tue, 10 Mar 2015 12:43:58 +0000
Subject: RE: [Minutus] Microwaving water
Dear Irene

Does your washing machine, dishwasher or indeed any appliance that you have in the house work with direct current?

No! - Why? Because alternative current is more efficient.
So the fact that the microwave oven works on alternative current is totally irrelevant. For example change the frequency setting of the microwave (as used in communication) and the water molecules no longer get agitated!

And the fact that you can get an effect from the microwaves at a distance from its generator, means that it is the effect of the microwaves produced and not the type and frequency of the electricity powering the system.

Look at it another way - a radio generator and receiver can be battery or mains (alternative current) powered.

What you find is that often there are circuits that convert the alternative current into direct current for it to work.

So the type of electricity coming through has nothing to do with the out put of various piece of equipment provided that the equipment has been designed to run with that type of out put.
As mentioned before, domestic induction cooking hobs use alternative currents as their input, but at much higher frequency than the 50 or 60 Hz used in US or Europe and usually in the range of 20-100 kHz to produce the rapid electromagnetic changes needed. Ditto for industrial induction heaters where you can heat to white hot a billet of iron or steel weighing 100 kg in a matter of seconds.
If you look at the design of the circuit of a microwave system, you will see that firstly it used very high voltage (via a transformer) and then a capacitor to produce direct current as the system works on a cathode and an anode (which means that the system actually works on direct current.)

From http://en.wikipedia.org/wiki/Cavity_magnetron

"The magnetic field is set to a value well below the critical, so the electrons follow arcing paths towards the anode. When they strike the anode, they cause it to become negatively charged in that region. As this process is random, some areas will become more or less charged than the areas around them. The anode is constructed of a highly conductive material, almost always copper, so these differences in voltage cause currents to appear to even them out. Since the current has to flow around the outside of the cavity, this process takes time. During that time additional electrons will avoid the hot spots and be deposited further along the anode, as the additional current flowing around it arrives too. This causes an oscillating current to form as the current tries to equalize one spot then another.[9]

The oscillating currents flowing around the cavities, and their effect on the electron flow within the tube, causes large amounts of microwaves to be created in the cavities. The cavities are open on one end, so the entire mechanism forms a single larger microwave oscillator. A "tap", normally a wire formed into a loop, extracts microwave energy from one of the cavities. In some systems the tap wire is replaced by an open hole, which allows the microwaves to flow into a waveguide ."
To sum up, it is the action of the microwaves at a narrow range of frequencies that agitates/rotates the polarised molecules (mainly of water) and thus produce heat the input electrical frequency is irrelevant.
Rgds

Soroush
From: minutus@yahoogroups.com [mailto:minutus@yahoogroups.com]
Sent: 09 March 2015 22:25
To: minutus@yahoogroups.com
Subject: Re: [Minutus] Microwaving water
Please see how CERN describe the process.

http://scitech.web.cern.ch/scitech/TopT ... ve_2.shtml
Microwave ovens use radio waves at a specifically set frequency to agitate water molecules in food.
Prove it?
It matters HOW they get "agitated" Soroush.

If your story here was true you could use direct current to make a miocrowave work. But that is not possible.

It is the alternating current that is involved in what you call "agitation" of the DIPOLAR molecules. it only works with molecules which have two electrically different poles.

That is not only water, but also oils and fats and other molecules. Hence you can heat and melt butter or coconut oil in the microwave, which also would not work if your theory about only water being hesated was valid.
Induction cooking uses an oscillating magnetic field (triggered by alternating current) to transfer heat.

Any oscillating magnetic field causes a magnetic flux (flux = flow) much like the technology used in a transformer, where proximity of windings is all that is needed, no actual touching, to transfer magnetic energy.

The metallic cookware gets in the way of the magnetic flow/flux by providing a resistance to this magnetic flux and the ineffieicnt flow of magnetic energy - the resistance in the metal - is expressed as heat in the metal. ie induced heat = induction cooking.

(Compare witih induction motors in electrical work. Induction cooking uses the induction principle plus the resistance one.)
Namaste,

Irene
As these water molecules get increasingly agitated they begin to vibrate at the atomic level and generate heat. This heat is what actually cooks food in the oven. Because all particles in the food are vibrating and generating heat at the same time, food cooked in the microwave cooks much more swiftly than food cooked in a conventional oven where heat must slowly travel from the outside surface of the food inward.
You seem to be confusing the action of microwaves with that induction heating alternative currents.

In induction heating, by the fact that alternative current is used, iron structures change directions rapid and thus cause heat. Hence the pan gets hot and not the cooker!
With microwaves, you make the water molecules, present in most things excited and vibrate rapidly.
Rgds

Soroush
From: minutus@yahoogroups.com [mailto:minutus@yahoogroups.com]
Sent: 09 March 2015 07:34
To: minutus@yahoogroups.com
Subject: Re: [Minutus] Microwaving water
Microwaves with certain wavelengths are absorbed by water molecules making them vibrate fast and thus cause heat and so can be used for cooking. Water in the food absorbs the microwave radiation, which causes the water to heat up and cook the food and this is also used in various industrial processes too.
Not exactly.
Microwave heating is done due the dipole nature of whatever it heats. Water is strongly dipolar and fats and oils less so. It is the fact that we use alternating current, combined with the dipole nature of the material in the microwave oven, that allows dipolar substances to get hot. The electrical current causes the sipolar molecules to rotate, and then when the current changes direction the dipolar molecules have to also change direction and rotate the other way round. This contant movement against each other, and constant change of direction of movement of the dipolar subtances, causes them to get h ot. The eleectrical energy is converted to heat energy.
This is the same principle as when you convert rubbing action of rubbing your hands together, into heat energy - or if you speed it up and slide down a rope, the converted energy that becomes heat, causes rope burns.
So the food in a microwave is cooked by spinning dipole molecules fast enough with alternating current causing direction change, to convert the energy involved ito heat energy - much the way energy isconverrted to heat energy to warm your hands or get rope burns.

There is no "radiation" involved.
Electromagnetic waves have a specific frequency. Calling it radiation is just misleading.

We do not think of sunshine as radiation and we do not think of the light by which you are typing as radiation either.

All electromagnetic waves whether the light in your office, or microwaves, will go in all directions (ie will radiate - a verb, to radiate)

That does not make them "radiation" - a noun with different implications.

The term "electromagnetic radiation" is only correct when used to describe electromagnetic forces going in all directions - ie radiating in all directions.

So microwaves radiate. They are not radiation.
Namaste,

Irene

--

Irene de Villiers, B.Sc AASCA MCSSA D.I.Hom/D.Vet.Hom.
P.O. Box 4703 Spokane WA 99220.
www.Furryboots.info

(Info on Feline health, genetics, nutrition & homeopathy)
"Man who say it cannot be done should not interrupt one doing it."
--

Irene de Villiers, B.Sc AASCA MCSSA D.I.Hom/D.Vet.Hom.
P.O. Box 4703 Spokane WA 99220.
www.Furryboots.info

(Info on Feline health, genetics, nutrition & homeopathy)
"Man who say it cannot be done should not interrupt one doing it."

No Roger!
Irene was saying that it was the alternative current going into the microwave system that did the job!
Irene had written:

"The electrical current causes the sipolar molecules to rotate, and then when the current changes direction the dipolar molecules have to also change direction and rotate the other way round. This contant movement against each other, and constant change of direction of movement of the dipolar subtances, causes them to get h ot. The electrical energy is converted to heat energy."
It would be like saying it is the electrical energy that washes your clothes in a washing machine! No it is the action of the rotation and the washing soap that does it as had been done through the ages. Electrical power takes the drudgery out of it.
It is correct that it is electrical power that produces the microwaves, however, it is NOT the electric current but microwaves that do the agitation to bipolar water or hydroxy containing molecules to cause heat! SIMPLE!
Rgds

Soroush
From: minutus@yahoogroups.com [mailto:minutus@yahoogroups.com]
Sent: 10 March 2015 13:34
To: minutus@yahoogroups.com
Subject: RE: [Minutus] Microwaving water
I think that Soroush and Irene are saying the same thing. Remember that light is both a particle and a wave at that level and smaller, so that at that level we can easily trip over semantics. I think that Soroush is saying that the atoms get agitated, and Irene is saying that the atoms switch direction because of the very temporary change in polarity. I don't see the difference.

Roger Bird
________________________________

To: minutus@yahoogroups.com
From: minutus@yahoogroups.com
Date: Tue, 10 Mar 2015 12:43:58 +0000
Subject: RE: [Minutus] Microwaving water
Dear Irene

Does your washing machine, dishwasher or indeed any appliance that you have in the house work with direct current?

No! - Why? Because alternative current is more efficient.
So the fact that the microwave oven works on alternative current is totally irrelevant. For example change the frequency setting of the microwave (as used in communication) and the water molecules no longer get agitated!

And the fact that you can get an effect from the microwaves at a distance from its generator, means that it is the effect of the microwaves produced and not the type and frequency of the electricity powering the system.

Look at it another way - a radio generator and receiver can be battery or mains (alternative current) powered.

What you find is that often there are circuits that convert the alternative current into direct current for it to work.

So the type of electricity coming through has nothing to do with the out put of various piece of equipment provided that the equipment has been designed to run with that type of out put.
As mentioned before, domestic induction cooking hobs use alternative currents as their input, but at much higher frequency than the 50 or 60 Hz used in US or Europe and usually in the range of 20-100 kHz to produce the rapid electromagnetic changes needed. Ditto for industrial induction heaters where you can heat to white hot a billet of iron or steel weighing 100 kg in a matter of seconds.
If you look at the design of the circuit of a microwave system, you will see that firstly it used very high voltage (via a transformer) and then a capacitor to produce direct current as the system works on a cathode and an anode (which means that the system actually works on direct current.)

From http://en.wikipedia.org/wiki/Cavity_magnetron

"The magnetic field is set to a value well below the critical, so the electrons follow arcing paths towards the anode. When they strike the anode, they cause it to become negatively charged in that region. As this process is random, some areas will become more or less charged than the areas around them. The anode is constructed of a highly conductive material, almost always copper, so these differences in voltage cause currents to appear to even them out. Since the current has to flow around the outside of the cavity, this process takes time. During that time additional electrons will avoid the hot spots and be deposited further along the anode, as the additional current flowing around it arrives too. This causes an oscillating current to form as the current tries to equalize one spot then another.[9]

The oscillating currents flowing around the cavities, and their effect on the electron flow within the tube, causes large amounts of microwaves to be created in the cavities. The cavities are open on one end, so the entire mechanism forms a single larger microwave oscillator. A "tap", normally a wire formed into a loop, extracts microwave energy from one of the cavities. In some systems the tap wire is replaced by an open hole, which allows the microwaves to flow into a waveguide ."
To sum up, it is the action of the microwaves at a narrow range of frequencies that agitates/rotates the polarised molecules (mainly of water) and thus produce heat the input electrical frequency is irrelevant.
Rgds

Soroush
From: minutus@yahoogroups.com [mailto:minutus@yahoogroups.com]
Sent: 09 March 2015 22:25
To: minutus@yahoogroups.com
Subject: Re: [Minutus] Microwaving water
Please see how CERN describe the process.

http://scitech.web.cern.ch/scitech/TopT ... ve_2.shtml
Microwave ovens use radio waves at a specifically set frequency to agitate water molecules in food.
Prove it?
It matters HOW they get "agitated" Soroush.

If your story here was true you could use direct current to make a miocrowave work. But that is not possible.

It is the alternating current that is involved in what you call "agitation" of the DIPOLAR molecules. it only works with molecules which have two electrically different poles.

That is not only water, but also oils and fats and other molecules. Hence you can heat and melt butter or coconut oil in the microwave, which also would not work if your theory about only water being hesated was valid.
Induction cooking uses an oscillating magnetic field (triggered by alternating current) to transfer heat.

Any oscillating magnetic field causes a magnetic flux (flux = flow) much like the technology used in a transformer, where proximity of windings is all that is needed, no actual touching, to transfer magnetic energy.

The metallic cookware gets in the way of the magnetic flow/flux by providing a resistance to this magnetic flux and the ineffieicnt flow of magnetic energy - the resistance in the metal - is expressed as heat in the metal. ie induced heat = induction cooking.

(Compare witih induction motors in electrical work. Induction cooking uses the induction principle plus the resistance one.)
Namaste,

Irene
As these water molecules get increasingly agitated they begin to vibrate at the atomic level and generate heat. This heat is what actually cooks food in the oven. Because all particles in the food are vibrating and generating heat at the same time, food cooked in the microwave cooks much more swiftly than food cooked in a conventional oven where heat must slowly travel from the outside surface of the food inward.
You seem to be confusing the action of microwaves with that induction heating alternative currents.

In induction heating, by the fact that alternative current is used, iron structures change directions rapid and thus cause heat. Hence the pan gets hot and not the cooker!
With microwaves, you make the water molecules, present in most things excited and vibrate rapidly.
Rgds

Soroush
From: minutus@yahoogroups.com [mailto:minutus@yahoogroups.com]
Sent: 09 March 2015 07:34
To: minutus@yahoogroups.com
Subject: Re: [Minutus] Microwaving water
Microwaves with certain wavelengths are absorbed by water molecules making them vibrate fast and thus cause heat and so can be used for cooking. Water in the food absorbs the microwave radiation, which causes the water to heat up and cook the food and this is also used in various industrial processes too.
Not exactly.
Microwave heating is done due the dipole nature of whatever it heats. Water is strongly dipolar and fats and oils less so. It is the fact that we use alternating current, combined with the dipole nature of the material in the microwave oven, that allows dipolar substances to get hot. The electrical current causes the sipolar molecules to rotate, and then when the current changes direction the dipolar molecules have to also change direction and rotate the other way round. This contant movement against each other, and constant change of direction of movement of the dipolar subtances, causes them to get h ot. The eleectrical energy is converted to heat energy.
This is the same principle as when you convert rubbing action of rubbing your hands together, into heat energy - or if you speed it up and slide down a rope, the converted energy that becomes heat, causes rope burns.
So the food in a microwave is cooked by spinning dipole molecules fast enough with alternating current causing direction change, to convert the energy involved ito heat energy - much the way energy isconverrted to heat energy to warm your hands or get rope burns.

There is no "radiation" involved.
Electromagnetic waves have a specific frequency. Calling it radiation is just misleading.

We do not think of sunshine as radiation and we do not think of the light by which you are typing as radiation either.

All electromagnetic waves whether the light in your office, or microwaves, will go in all directions (ie will radiate - a verb, to radiate)

That does not make them "radiation" - a noun with different implications.

The term "electromagnetic radiation" is only correct when used to describe electromagnetic forces going in all directions - ie radiating in all directions.

So microwaves radiate. They are not radiation.
Namaste,

Irene

--

Irene de Villiers, B.Sc AASCA MCSSA D.I.Hom/D.Vet.Hom.
P.O. Box 4703 Spokane WA 99220.
www.Furryboots.info

(Info on Feline health, genetics, nutrition & homeopathy)
"Man who say it cannot be done should not interrupt one doing it."
--

Irene de Villiers, B.Sc AASCA MCSSA D.I.Hom/D.Vet.Hom.
P.O. Box 4703 Spokane WA 99220.
www.Furryboots.info

(Info on Feline health, genetics, nutrition & homeopathy)
"Man who say it cannot be done should not interrupt one doing it."