Microwave Technology (Physics)

[huejas]

So i picked this topic for my physics essay thinking that it was about microwaves (that you heat up food and shit in), but it turns out its actually about micro-waves (like waves that are micro) lol ....so i go to wikipedia and search that shit, and i don't understand half of it Can anyone get me started, or put me on the right track. Also i need a good website for info.

Halp!?!?

[jeansl10]

well i think microwaves are produced by a magnetron (w/ever that is), the microwaves then go throught the food and make the water molecules vibrate thus producing heat

thats what i know

[[SD]Master_Wong]

its radiation (light also been within the same spectrum along with infra red uv etc all forms of radiation)

erm do you know about wavelengths and such? if not it could take a while to explain

although without saying how they are produced i can tell you much like any other form of radiation it heads inside out, so your food in theory should be cooked in the center before the outside granted its not always the case but its why you dont put living things in the microwave

[Rainigul]

its radiation (light also been within the same spectrum along with infra red uv etc all forms of radiation)

erm do you know about wavelengths and such? if not it could take a while to explain

although without saying how they are produced i can tell you much like any other form of radiation it heads inside out, so your food in theory should be cooked in the center before the outside granted its not always the case but its why you dont put living things in the microwave

When I put my food in the microwave, it's generally really hot around the outside, and ice cold in the middle.

Tha fucks up with that?

[DarkJackal]

its radiation (light also been within the same spectrum along with infra red uv etc all forms of radiation)

erm do you know about wavelengths and such? if not it could take a while to explain

although without saying how they are produced i can tell you much like any other form of radiation it heads inside out, so your food in theory should be cooked in the center before the outside granted its not always the case but its why you dont put living things in the microwave

When I put my food in the microwave, it's generally really hot around the outside, and ice cold in the middle.

Tha fucks up with that?

Microwaves coming from around the food?

[huejas]

its radiation (light also been within the same spectrum along with infra red uv etc all forms of radiation)

erm do you know about wavelengths and such? if not it could take a while to explain

although without saying how they are produced i can tell you much like any other form of radiation it heads inside out, so your food in theory should be cooked in the center before the outside granted its not always the case but its why you dont put living things in the microwave

Yes i know about wavelengths.
The essay is to talk about microwave technology(in tv's, cell phones....microwaves too i suppose) not ONLY microwave ovens, however it must explain physics of the topic. I suppose it may be explained by using the microwave oven for examples.

[chickenfeather]

This is always a good site.
http://home.howstuffworks.com/microwave.htm

Also, there are some interesting phenomena dealing with metal and grapes in microwaves, like how it's ok to put metal in a microwave and how grapes generate plasma.
Some links related to those topics are :
http://home.att.net/~mrmicrowave/docs/y ... metal.html
http://www.barnesos.net/homepage/lpl/grapeplasma/

There are also applications of microwaves in welding and crowd control.

[takolin]

well i think microwaves are produced by a magnetron (w/ever that is), the microwaves then go throught the food and make the water molecules vibrate thus producing heat

thats what i know

A microwave oven works by passing non-ionizing microwave radiation, usually at a frequency of 2.45 gigahertz (GHz) (a wavelength of 12.24 centimetres (4.82 in), through the food. Microwave radiation is between common radio and infrared frequencies. 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 of the microwaves. This molecular movement creates heat as the rotating molecules hit other molecules and put them into motion.

Microwave heating is more efficient on liquid water than on fats and sugars (which have less molecular dipole moment), and also more efficient than on frozen water (where the molecules are not free to rotate).[5] Microwave heating is sometimes explained as a resonance of water molecules, but this is incorrect: such resonance only occurs in water vapor at much higher frequencies, at about 20 GHz.[6] Moreover, large industrial/commercial microwave ovens operating at the common large industrial-oven microwave heating frequency of 915 MHz (0.915 GHz), also heat water and food perfectly well.[7]

A common misconception is that microwave ovens cook food from the "inside out". In reality, microwaves are absorbed in the outer layers of food in a manner somewhat similar to heat from other methods. The misconception arises because microwaves penetrate dry non-conductive substances at the surfaces of many common foods, and thus often induce initial heat more deeply than other methods. Depending on water content, the depth of initial heat deposition may be several centimetres or more with microwave ovens, in contrast to broiling (infrared) or convection heating, which deposit heat thinly at the food surface. Penetration depth of microwaves is dependent on food composition and the frequency, with lower microwave frequencies (longer wavelengths) penetrating better.

[Stephanus]

Radiation:

http://en.wikipedia.org/wiki/Radiation

From there you can visit electromagnetic radiation:

http://en.wikipedia.org/wiki/Electromagnetic_radiation

Frome there on microwaves:

http://en.wikipedia.org/wiki/Microwave
(you should read all articles linked in the "see also" part here)


Effects on health:

http://en.wikipedia.org/wiki/Electromag ... and_health

My 2 cents.

ps:
Dont EVER put living thing in microwave ovens, or metal, or eggs(anything wich is sealed from the outside -> bomb). If you have to write some interesting things about hazards and such search for this:
(cat+micro oven, how to make your own lightning sphere etc:)...)

[jeansl10]

well i think microwaves are produced by a magnetron (w/ever that is), the microwaves then go throught the food and make the water molecules vibrate thus producing heat

thats what i know

A microwave oven works by passing non-ionizing microwave radiation, usually at a frequency of 2.45 gigahertz (GHz) (a wavelength of 12.24 centimetres (4.82 in), through the food. Microwave radiation is between common radio and infrared frequencies. 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 of the microwaves. This molecular movement creates heat as the rotating molecules hit other molecules and put them into motion.

Microwave heating is more efficient on liquid water than on fats and sugars (which have less molecular dipole moment), and also more efficient than on frozen water (where the molecules are not free to rotate).[5] Microwave heating is sometimes explained as a resonance of water molecules, but this is incorrect: such resonance only occurs in water vapor at much higher frequencies, at about 20 GHz.[6] Moreover, large industrial/commercial microwave ovens operating at the common large industrial-oven microwave heating frequency of 915 MHz (0.915 GHz), also heat water and food perfectly well.[7]

A common misconception is that microwave ovens cook food from the "inside out". In reality, microwaves are absorbed in the outer layers of food in a manner somewhat similar to heat from other methods. The misconception arises because microwaves penetrate dry non-conductive substances at the surfaces of many common foods, and thus often induce initial heat more deeply than other methods. Depending on water content, the depth of initial heat deposition may be several centimetres or more with microwave ovens, in contrast to broiling (infrared) or convection heating, which deposit heat thinly at the food surface. Penetration depth of microwaves is dependent on food composition and the frequency, with lower microwave frequencies (longer wavelengths) penetrating better.

what i meant

[iGod]

Microwaves are between the visible spectrum and radiowaves

well theres a wikipedia article out there about it already posted, btw. I wouldn't start off with microwave ovens in the essay, only note them as one of the things we use them for

[huejas]

thx for all the info guys, ill read it all when i get home today so keep it coming

[huejas]

Microwaves are between the visible spectrum and radiowaves

well theres a wikipedia article out there about it already posted, btw. I wouldn't start off with microwave ovens in the essay, only note them as one of the things we use them for

lol, i started with microwave ovens, to then easy into the other stuff its used in

This is always a good site.
http://home.howstuffworks.com/microwave.htm

Also, there are some interesting phenomena dealing with metal and grapes in microwaves, like how it's ok to put metal in a microwave and how grapes generate plasma.
Some links related to those topics are :
http://home.att.net/~mrmicrowave/docs/y ... metal.html
http://www.barnesos.net/homepage/lpl/grapeplasma/

There are also applications of microwaves in welding and crowd control.

+

Radiation:

http://en.wikipedia.org/wiki/Radiation

From there you can visit electromagnetic radiation:

http://en.wikipedia.org/wiki/Electromagnetic_radiation

Frome there on microwaves:

http://en.wikipedia.org/wiki/Microwave
(you should read all articles linked in the "see also" part here)


Effects on health:

http://en.wikipedia.org/wiki/Electromag ... and_health

My 2 cents.

ps:
Dont EVER put living thing in microwave ovens, or metal, or eggs(anything wich is sealed from the outside -> bomb). If you have to write some interesting things about hazards and such search for this:
(cat+micro oven, how to make your own lightning sphere etc:)...)

i will check these out.....thanks for the ps

well i think microwaves are produced by a magnetron (w/ever that is), the microwaves then go throught the food and make the water molecules vibrate thus producing heat

thats what i know

A microwave oven works by passing non-ionizing microwave radiation, usually at a frequency of 2.45 gigahertz (GHz) (a wavelength of 12.24 centimetres (4.82 in), through the food. Microwave radiation is between common radio and infrared frequencies. 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 of the microwaves. This molecular movement creates heat as the rotating molecules hit other molecules and put them into motion.

Microwave heating is more efficient on liquid water than on fats and sugars (which have less molecular dipole moment), and also more efficient than on frozen water (where the molecules are not free to rotate).[5] Microwave heating is sometimes explained as a resonance of water molecules, but this is incorrect: such resonance only occurs in water vapor at much higher frequencies, at about 20 GHz.[6] Moreover, large industrial/commercial microwave ovens operating at the common large industrial-oven microwave heating frequency of 915 MHz (0.915 GHz), also heat water and food perfectly well.[7]

A common misconception is that microwave ovens cook food from the "inside out". In reality, microwaves are absorbed in the outer layers of food in a manner somewhat similar to heat from other methods. The misconception arises because microwaves penetrate dry non-conductive substances at the surfaces of many common foods, and thus often induce initial heat more deeply than other methods. Depending on water content, the depth of initial heat deposition may be several centimetres or more with microwave ovens, in contrast to broiling (infrared) or convection heating, which deposit heat thinly at the food surface. Penetration depth of microwaves is dependent on food composition and the frequency, with lower microwave frequencies (longer wavelengths) penetrating better.

thx for the summary but this is really too much about microwave ovens to include in my essay

[Amelie]

http://www.dailymotion.com/video/x5odhh ... le-microon

[huejas]

http://www.dailymotion.com/video/x5odhh_pop-corn-telephone-portable-microon

seen a vid liek this before...but i heard it was fake

anyways i got 2/4 pages, kinda stuck regarding other applications of the microwaves (other then microwave oven)

[huejas]

http://www.dailymotion.com/video/x5odhh_pop-corn-telephone-portable-microon

seen a vid liek this before...but i heard it was fake

anyways i got 2/4 pages, kinda stuck regarding other applications of the microwaves (other then microwave oven)

done, 5 pages thx for any help