Uploaded January 2017 | Updated September 2026, 2 weeks ago

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You have heard that light only goes at 300,000,000 m/s in the vacuum and that it goes slower in materials. Is that actually true? Maybe not. It depends...
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VIDEO ANNOTATIONS

Is Math the Language of the Universe?
youtu.be/inPcQeYWVT8

Does Light Have Mass?
youtu.be/ueuwWiR-Dw4

Why Are Some Things Transparent?
youtu.be/wDu0KMdDD1I
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HUGE THANK YOU TO THESE PATRONS:

** Nikko Lai, Andy Kirkham, Evgeny **
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EXTRA INFO LINKS

Sixty Symbols on Light Slowing:
youtu.be/CiHN0ZWE5bk
youtu.be/YW8KuMtVpug

Huygen's Principle:
en.wikipedia.org/wiki/Huygens%E2%80%93Fresnel_principle

Fermat's Principle:
http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/Fermat.html#c3

Wave Interference:
http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/interfcon.html
en.wikipedia.org/wiki/Interference_(wave_propagation)
physicsclassroom.com/class/waves/Lesson-3/Interference-of-Waves

Refractive Index:
http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/refr.html
http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/indrf.html
engineeringtoolbox.com/refractive-index-d_1264.html
en.wikipedia.org/wiki/Refractive_index

Drag:
http://hyperphysics.phy-astr.gsu.edu/hbase/airfri.html
http://hyperphysics.phy-astr.gsu.edu/hbase/airfri2.html
en.wikipedia.org/wiki/Drag_(physics)
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LIGHT SLOWS COMMENTS

TJF588:
youtube.com/watch?v=ueuwWiR-Dw4&lc=z13atzdo2ojqw54yz04cjhqj2tvrxhgwej4

Tommy WizOh:
youtube.com/watch?v=ueuwWiR-Dw4&lc=z12bhb4qmvvihdrbb04cjlpgupngzjkp1sw0k

Tony Skagerlund:
youtube.com/watch?v=ueuwWiR-Dw4&lc=z13xxxopauqzyxmqu04ceb2i1zzhida4ujk

Noah Keith:
youtube.com/watch?v=ueuwWiR-Dw4&lc=z135zh15srissfhg004citxhgznksn4hryo0k
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COMMENT RESPONSES

frib75 - Math isn't a Language:
youtube.com/watch?v=inPcQeYWVT8&lc=z13gvdo5bum3zj2kj23iifbaysy0yfisj

ScienceMaths2012 - Physical Axioms:
youtube.com/watch?v=inPcQeYWVT8&lc=z13vwnaquo2ugvawt04cd3hr4si0xlqosao

Thedarkfly - Symbols in what Langauge:
youtube.com/watch?v=inPcQeYWVT8&lc=z13xzvk51tjbyrd01224wlajhsuaylkpm04

Rick Clark - Units of Measure:
youtube.com/watch?v=inPcQeYWVT8&lc=z13dwleqpk2py1cjx04cf5zrdyqpdxgimy40k
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