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Can microwaves melt metal? As far as I know, it can't melt a spoon no matter how long you put it in a microwave oven. Is it possible to get microwaves to melt metal?
A microwave oven works by passing microwave radiation, usually at a frequency of 2.45 GHz (a wavelength of 12.24 cm), through the food. Water, fat, and other substances in the food absorb energy from the microwaves in a process called dielectric heating. Many molecules (such as those of water) are electric dipoles, meaning that they have a positive charge at one end and a negative charge at the other, and therefore rotate as they try to align themselves with the alternating electric field induced by the microwaves. This molecular movement creates heat as the rotating molecules hit other molecules and put them into motion.
And the currents could for sure cause resistive Joule heating, which could heat and melt the metal?vanesch said:Well, microwaves induce currents in metals.
Oh yes! I remember that! I thought it was very cool and I might try it myself in my garage sometime.jessb said:http://www.popsci.com/popsci/how20/15499aa138b84010vgnvcm1000004eecbccdrcrd.html
try that.
or, don't, because it's quite dangerous.
ShawnD said:I was always told that microwave ovens send out magnetic waves as well as microwaves. Things capable of soaking up a magnetic field (iron) will do so, and it induces a current. If the metal object in the microwave is uniform and well-connected, like a spoon, it will just heat up. If the object has lots of spaces and is poorly connected to dissipate charge, differences in charge will build up and the item will spark (steel wool).
Put a spoon in the microwave and see what happens. Put steel wool in the microwave and see what happens. Better yet, put steel wool in a mixture of sugar and drano; that's the most fun thing ever! I ruined a microwave diong that because the fire got out of control and it coated the microwave with carbon. It couldn't even heat up a glass of water after that.
Roy Edmundson said:Similar sparking occurs if you put an aluminium foil plate in the microwave with a stainless steel spoon on it, but any single solid piece of metal doesnt.
vanesch said:Well, microwaves induce currents in metals.
f3nr15 said:Oh OK so microwaves have a separate magnetic flux.
lpfr said:Not a separate one. All electromagnetic waves, including microwaves, light and gamma rays, have an electric field and a magnetic field, whose amplitudes are related (proportionnaly).
lpfr said:Yes, I know the graph. You find it in almost every EM textbook. It is, of course, correct, but I found it misleading to most of my students.
So I did another drawing of an electromagnetic plane wave (a wave that comes from far away). Imagine a rectangular chunk of space, chopped in slices as an "American sandwich bread".
In the first slice drawn, the electric field E is vertical and downward and the magnetic field B is horizontal and directed to the right. This is so in all the volume of the slice (the drawing displays just a "square" of the slice which is very much large.
The amplitude of both fields are maximum in middle of the slice (between the two faces) and decreases as a sinusoid to attain zero just at the faces of the slice.
The situation is identical for each other one slice. In the slices in-between the direction of both fields is just reversed.
Now, all the slices move at the speed of light v (or c if it is in vacuum) as the arrow indicates.
The thickness of two slices is the wavelength of the wave.
The real dimensions of the slices depend on the wavelength. For AM radio waves you would be a microscopic spot in the drawing. But, if the EM waves are light, it is the drawing which would be a microscopic spot in your pupil.
Think about this drawing. If you "see" it, then you will be able to understand the other one and realize that, of course, it is also correct.
f3nr15 said:I saw one that looked like a sine curve I mean, each time it completed a 900 period (clarify my wave terminology) it would go to the z-axis which is the magnetic field. Another 900 later it would go back to the y-axis which is the electric field.
And because it was a sine curve, as x was increasing, the amplitude also changed hence a changing electric led then changing magnetic field and vice versa that's how I perceived it.
Microwaves are a form of electromagnetic radiation that can cause molecules to vibrate rapidly, generating heat. When metal is exposed to microwaves, the electric fields interact with the free electrons in the metal, causing them to move rapidly and collide with other particles, creating heat and eventually melting the metal.
While most metals will not melt in a household microwave, some types of metal with a high melting point, such as gold and silver, can be melted with specialized industrial microwaves. It is important to note that attempting to melt any metal in a household microwave can be dangerous and should not be done.
Yes, there are safety concerns when using microwaves to melt metal. First, the metal must be completely clean and free of any impurities or moisture to prevent sparks or explosions. Additionally, the metal must be placed in a microwave-safe container that is specifically designed for high-temperature use. It is important to follow all safety precautions and guidelines when attempting to melt metal in a microwave.
The power needed to melt metal in a microwave depends on the type of metal and the size and shape of the metal piece. Industrial microwaves used for metal melting typically have a power output of 1000-3000 watts. Household microwaves typically have a power output of 600-1500 watts, which may not be enough to melt metal.
Yes, there are practical applications for melting metal with microwaves. One example is in the field of metallurgy, where microwaves can be used to melt and mix metals for creating alloys. Microwaves can also be used in the recycling industry to melt scrap metal for reuse. Additionally, microwaves can be used for precision heating of small metal components in industries such as electronics and medicine.