How Microwave Lenses REALLY Work!

Comments · 578

• PR

  @profdc9501 · 3 years ago · pinned

  A lot of vibrational absorption bands that absorb microwave frequencies are due to the variation in local sites of atoms in a polymer.  It's not that PTFE or HDPE don't have resonance, it's that because they're very regular polymers, the resonances tend to be the same at each site rather than varying from site to site.  Because there are sharp resonance frequencies, most of the microwave spectrum is unaffected by the resonances.  For example, in PTFE or HDPE, the C-F and C-H bonds respective are identical because of the repetitiveness of the polymer chain, and so each C-F and C-H bond looks the same relative to its neighbors, except perhaps the few bonds on the end of the chain, and perhaps where there are crosslinks if there are crosslinks between the chains.  Therefore they all behave similarly and have the same resonances.    For this reason regularity of the polymer is very important because this tends to cluster the resonances into a few sharp bands that can be avoided.

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• MR

  @Mr.Kim.T · 3 years ago

  To heat up a couple of dinner plates in a microwave I put some water in the bottom plate and place the other plate upside-down on top and heat for a couple on minutes. This works well. So to heat a couple of bowls I did the same, I placed some water in the bottom bowl, but instead of putting the top bowl upside-down, I nested it the right-side up. This created a curved lens of water in the bottom bowl that focused the microwave energy down onto the plastic spider bracket supporting the glass turntable. The spider bracket caught on fire! Once the plastic in the spider bracket started the carbonise, this seemed to concentrate the microwave energy in the carbon and a runaway effect ensued. Lesson… don’t put nested bowls separated by water in a microwave!

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• MA

  @MachiningandMicrowaves · 3 years ago (edited)

  Refraction is REALLY weird.  Even if you don't go into the fine detail of the quantum-mechanical workings, the mechanism of refraction at microwave frequencies at the molecular level is not what most folks think. My little aside about Ibn Sahl and medieval Persian rather missed the fact that the image in annotated in Arabic. My late wife Caroline would have spotted that in an instant and corrected me.

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• DA

  @dandeeteeyem2170 · 3 years ago

  Best teacher ever. This destroyed some stumbling blocks I've had for years when trying to visualise radio. Well done

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• MA

  @MachiningandMicrowaves · 3 years ago

  NEW VERSION WITH THE MISSING BITS AFTER <a href="https://www.youtube.com/watch?v=_4vv3N5UpW0&amp;t=1380">23:00</a> added back in. &nbsp;The Almighty Algorithm is going to be annoyed &nbsp;with me!

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• TH

  @thomasgreenfoto2059 · 3 years ago

  I really apriciate your dedication to comunication.

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• BA

  @Barely_Creative · 3 years ago

  Excellent! Glad to see the extra 3 minutes :D

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• CR

  @Critter145 · 3 years ago

  This is one of the most interesting videos I’ve seen in a while. Thank you so much.

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• OH

  @ohbeardedone9253 · 3 years ago

  Dude, you one of the best science YouTubers. You cover the forefront of technology and you engage. You’re a rare breed. I am gonna higher you when I start up my stealth drone company.

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• MA

  @mattholden5 · 3 years ago

  Neil, your description of atomic interaction with an electromagnetic wave is the most cohesive explanation of refraction I&apos;ve ever heard. Nice to see Aimee make an appearance, as well. Thanks for another very interesting video.

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• JI

  @jimsvideos7201 · 3 years ago

  RF is perinally bizarre, but thank you for taking along!

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• PT

  @ptonpc · 3 years ago

  Thanks for continuing to inform us in a clear way.

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