Electromagnetic Spectrum: Microwaves

Electromagnetic radiation which has a longer wavelength (between 1 mm and 30 cm) than visible light. Microwaves can be used to study the Universe, communicate with satellites in Earth orbit, and cook popcorn.

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Measuring the electromagnetic spectrum

You actually know more about it than you may think! The electromagnetic (EM) spectrum is just a name that scientists give a bunch of types of radiation when they want to talk about them as a group. Radiation is energy that travels and spreads out as it goes -- visible light that comes from a lamp in your house and radio waves that come from a radio station are two types of electromagnetic radiation. Other examples of EM radiation are microwaves, infrared and ultraviolet light, X-rays and gamma-rays. Hotter, more energetic objects and events create higher energy radiation than cool objects. Only extremely hot objects or particles moving at very high velocities can create high-energy radiation like X-rays and gamma-rays.

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Microwaves are electromagnetic waves with wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz (0.3 GHz) and 300 GHz. This broad definition includes both UHF and EHF (millimeter waves), and various sources use different boundaries. In all cases, microwave includes the entire SHF band (3 to 30 GHz, or 10 to 1 cm) at minimum, with RF engineering often putting the lower boundary at 1 GHz (30 cm), and the upper around 100 GHz (3mm).

Apparatus and techniques may be described qualitatively as "microwave" when the wavelengths of signals are roughly the same as the dimensions of the equipment, so that lumped-element circuit theory is inaccurate. As a consequence, practical microwave technique tends to move away from the discrete resistors, capacitors, and inductors used with lower frequency radio waves. Instead, distributed circuit elements and transmission-line theory are more useful methods for design and analysis.

Open-wire and coaxial transmission lines give way to waveguides and stripline, and lumped-element tuned circuits are replaced by cavity resonators or resonant lines. Effects of reflection, polarization, scattering, diffraction and atmospheric absorption usually associated with visible light are of practical significance in the study of microwave propagation. The same equations of electromagnetic theory apply at all frequencies.

While the name may suggest a micrometer wavelength, it is better understood as indicating wavelengths very much smaller than those used in radio broadcasting. The boundaries between far infrared light, terahertz radiation, microwaves, and ultra-high-frequency radio waves are fairly arbitrary and are used variously between different fields of study.

Electromagnetic waves longer (lower frequency) than microwaves are called "radio waves". Electromagnetic radiation with shorter wavelengths may be called "millimeter waves", terahertz radiation or even T-rays. Definitions differ for millimeter wave band, which the IEEE defines as 110 GHz to 300 GHz.

Above 300 GHz, the absorption of electromagnetic radiation by Earth's atmosphere is so great that it is effectively opaque, until the atmosphere becomes transparent again in the so-called infrared and optical window frequency ranges.

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[Roobitz]

I love this channel because I can always come on here and there is no drama of any sort, no face trying to promote themselves, just someone dedicated to the advancement of scientific knowledge sharing that desire with the world. It's like a breath of fresh air, to be cliche.

[seeqer]

(First Statement) "Microwaves can pop your popcorn". I always wondered what was in those pills they took in "Barbarella"

[YourBrainOnReligion]

Awesome video... very informative and very well produced. Thank you.

[SteilLaw]

Interesting video.
We are beginning to live in a microwaving world :P

[jmm]

@th3dig1tal0n3 i saw an article that Chandra uses both X-ray and microwaves to plot were black holes are

[Davelantor]

@helpvidz Microwaces are a necessary "commodity" for which demand is constant.
also as staples as in the office supply ... could mean that they are the backbone [what keeps it together] of the communication or etc. industry :P

[Nohrel]

I don't drink and don't smoke... 6 days now. I don't understand a thing from this vid. 1979, september and Japanese. Those are the 3 things i remember from this vid. Nice vid btw. im definitely a fan.

[granddad]

I enjoy the lay concept of microwaves. I just want to see a 'set-up' like in 'Man with the Golden Gun'... where sunlight is transformed into microwaves and stored as electricity in several cauldrons of liquid helium! Are superconducting storage batteries feasible? I'd be happy if you could store it all up into compressed liquid hydrogen... an inexhaustible fuel cell system? Gas qualification has problems, but beaming energy hasn't been demonstrated as competitive to wire transmission or

[Riotboy]

Cool. But needs more talk about a Space.

[Dogsthumb]

Would it be possible to use cosmic background radiation as a form on night vision?
2:46

[PhillipThunderGrunge]

anybody see on the news somewhere that cosmologists/scientists found the oldest structures in the universe?...they said they found "cosmic strings"
anybody hear about that? I'd love to learn more...

[huyked]

@ 1:20 for global warming doubters. Science truly at work, not conspiracy theorists... who could use their time more productively somewhere else.

[oceantv-pppq]

Happy new year everyone... Looking forward to 2017

[Lumpiluk]

Except the Apple advertisement - great video!

[JimboJitsu]

Great video thanks for sharing this is very cool!

[siva]

Its very good and covered the details needed eff
ectively

[chvits]

Some question in my mind are answered. Thanks!

[keeperkai]

@CyberNeticRodent
I know, I was with you from the very first post....

[granddad]

a comeback. Matter of fact, there was a flirtation with hypersonic underground electromagnetic rail levitation in the 80s.... trains that could move megatons of freight and people with costs competitive with town buses... from New York to Phoenix in 54 minutes? Amazing how we just kind of backed off and pinnacled our technology on data processing and telecommunications? Maybe we need to start having some optimism & have great dreams again.

[granddad]

commercial electrical generators. But potentially with generation & transmission simplified, you can create a useful market for these resources. No greenhouse gases or carbon particulates or radioactive fuel rod disposal needed. Microwave power seems to have broader applications in Space development?
Gigantic orbital solar stacks absorbing raw sunshine and making beams that can be re-attenuated on the Earth's surface as electricity! Could you imagine a power bill of $3 a year? Trains could make