Double Vision - Sixty Symbols

A huge crystal of calcite is used to demonstrate birefringence, a side-effect of light's refraction through certain materials.

Featuring Professor Mike Merrifield.

This project features scientists from The University of Nottingham

Sixty Symbols videos by Brady Haran

[maskedmarvyl]

This is the Only video I've seen about birefringence that explains what is happening with light's interaction with the material on an atomic level. It finally gave me the explanation I've been looking for. I almost feel like crying.
Most of the other videos use a strictly mathematical explanation that involves derivatives and calculus to explain propagation through the crystal using symbols and methods they never explain, and never explain the physical interaction of unpolarized light as it passes through the crystal.

It's very rare that you get a professor that actually cares about explaining scientific principles without simply turning it into a calculus problem that they assume you already understand.

[TeamFlamingStones]

Wow, I've never understood refraction before now, and it was just so simple! I mean, I'm sure his explanation was simplified as well, but in all my years in public school, no one even tried!

[iCantMakeMovies]

Brady, I like how you ask the exact questions I ask just after I shout them at my computer screen. It's like we have a special connection.

[alandouglas]

Where did he get that white and gold shirt?

[rageagainstthebath]

Right now I work on my masters thesis, which is a HAUP aparatus (for measuring some of the optical properties of materials). Not more than a week ago I successfully measured a delta of a half wave plate, using modules that I constructed. So cool to see it here. :)

[MiroslavSmola]

The addition of practical usage will be great. In periodic tables of videos there is always example where we can find that particular element or chemical compound.

[LuciolaSama]

I'm a PhD student in molecular biology and know a fair share of professors in the field who explain their stuff enthousiastic, but hearing Professor Merrifield (and Professor Copeland for that matter) makes me wonder if I shouldn't have studied physics instead.. :)

[rjal]

You should have a look at the Michel-Levy chart. It links the different colours to the different crystal structures and orientations you get when looking at really thin sections of rocks. Some of it's very beautiful.

[knasbollolo]

So here we are, at the end of watching all the currently released sixtysymbols videos. It sure was an awesome journey. Really looking forward to new videos :)

[thenorup]

I love this approach!
TV would cut just before the guy says "explain that", but this video goes on for 5 times the length!

[pnshigalyov]

It's one of the themes from Against the Day by Thomas Pynchon, the cover reproduces the effect and there is a chapter called Iceland Spar.

[Surfurplex]

Remember that there are almost an infinite energy gaps, so there are very many energies which are able to excite the electrons. Visible light falls within a small range of energy compared to the entire EM spectrum, and doesn't match any of the energy gaps in glass/sterile water. There is, though, one (or several) possible energy gap smaller than light (IR), and many gaps larger than light.

[DenfordBerriman]

I'm glad you did that thing with the polaroid as well. That was great

[taylorraywhitehead]

More videos with this guy, he is great.

[scottseptember]

Actually, in the Gargamelle video by Brady, the physicist within the video stated that neutral current was caused by the "Weak force", which involves quarks (such as those that neutrons within a neutron star consist of).

[Misasaurolophus]

I know what I'm doing during our minerals lab in Geology now! This is AWESOME!
You have no idea how amazed I am at this having worked with minerals in previous geology classes and never knowing of this property. =O

This is probably my favorite Sixty Symbols video thus far!

[FASTFASTmusic]

it's travelling at the speed of light through calcium carbonate. Not the speed of light in a vacuum. Light travels at different speeds depending on the material, even air - that's why you get mirages. The photons that come out of the material are not the same ones that went in, they get absorbed and re-emitted by the material, which takes time.

[SonOfFurzehatt]

I know it's been a while since you left that comment, but the navigational properties of Iceland spar have been tested and published in a journal by Guy Ropars et al. Polarised light can penetrate thin cloud and the crystal is able to detect when it is pointed at the Sun through this. There are no contemporaneous accounts of its use by the Vikings, but it has been found on one 16th Century shipwreck.

[cristianfcao]

Hey Brady! Here's a video I'd love to see: One about the "Brian Cox Effect" (or the Neil deGrasse Tyson Effect, or the Brady Haran Effect :-). That is: about the impact of the work that you guys do to motivate people in following careers in STEM fields (science, technology, engineering and maths). I've read that in the UK statistics show a greater interest among young pppl in STEM fields, and that it is partly attributed to Cox's popularity. Interviews with students @ Nott. can be interesting.

[Surfurplex]

IR light is absorbed as well, so visible light is just inbetween the energy states needed to excite the electrons (English isn't my main language, so I'm not all to familiar with the semantics here). As for the phase velocity for light, I believe that the freq. increases and wavelength decreases thus conserving the energy, but I don't know why off the top of my head. Read Feynman's paper "The Principal of Least Time", it explains the subject quite good. Feynman was awesome.