Shining a laser through a light bulb can reveal the structure of DNA

[@SteveMould]

I made the animations myself on this one, so they're... simple. Hope you like them! The sponsor is Skillshare. Get 2 months of Skillshare Premium for free at: skl.sh/stevemould5

[@SteveMould]

The double slit animation with the two wave fronts!

[@wierdalien1]

This. This is the bomb. This whole idea. Its execution. To steal a phrase from Matt, it's so good!

[@grandmasternyx1514]

Did you also do the helix DNA animation aswell? Not bad if so. . . Thank you for another thought provoking video for that matter.

[@exazebra]

You'll have to try harder to make something I won't like Steve.

[@ИванСнежков-з9й]

BTW, the lightbulb wire is also double helix, however it is helix inside helix, one small and one big.

[@theoriginaledi]

Oh. My. Gosh. I taught both biology and physics for nearly 20 years and I'm ashamed to say that I've never quite been able to wrap my mind fully around how Watson and Crick got from that image to "Oh, it's a double helix, OBVIOUSLY!" :-) I understood most of the general ideas but somehow never could see the whole big picture. Anyway... I click here and less than 10 minutes later, eureka! Your literal light bulb turned on the metaphorical one in my brain. Thank you so much for this very clear explanation and excellent demonstration. You're the coolest!

[@olmostgudinaf8100]

Same here. Only without the teaching part.

[@kian8382]

I wished all my teachers were as enthusiastic as you are, and as brilliant as Steve can explain things and inspire people but not all the teachers share that passion, to some it's just a job, and I understand being a teacher is so much more than just teaching itself, we all have our own set of skills and shortcomings.

[@GijsvanDam]

Same here. (Without the teaching part) I knew the picture of the crystallography, but never in my life understood how it was understood to represent a helical structure)

[@YossiSirote]

Me toooooo!!!

[@thewolfin]

LSD helped.

[@edeneden97]

Love the shot at 4:35 and change of focus!

[@SteveMould]

I must say, I was pretty pleased with that myself!

[@thaitichi]

@@SteveMould You just keep raising the bar. More work for you, but better videos for us. Keep up the great work! It's much appreciated.

[@BlameItOnGreg]

I saw the initial shot and as the explanation was going I was like, “no, he isn’t...” and then you did, and I was like “top notch, top notch. 👏🏻”

[@vyomnahakvihangbodh6800]

@@SteveMould can you share the camera details please? 😁

[@SteveMould]

@@vyomnahakvihangbodh6800 Panasonic GH5 with a Panasonic Lumix G Macro 30mm Lens!

[@Chiaros]

If all teachers were like Steve, we'd be living in a utopia. You're a real inspiration, thank you.

[@jude9192]

Marky what teachers do you know?

[@JimC]

@Marky People who have a passion (or at least the willingness to do the necessary work) for *acquiring* knowledge can get something from almost any teacher. Those are the people who get A's.

[@PME]

Keep in mind that it takes Steve a lot of time to find all this information and to film it. It is somewhat harder for teachers because they have to transfer this knowledge multiple times and help students who have problems understanding the subject. It takes more time than you might think.

[@HatiKeseorangan]

Same here.... I wish I will learn with u and Elon musk...

[@GenoLoma]

Agreed.. if he and Tech Ingredients got together.. whoa!!

[@jackgreene491]

I've been shown this image at least 3 times in various college classes, and no teachers ever bothered to explain why the cross was indicative of the helix. I always assumed that the light was passed down the center of the double helix, rather than across it. Thank you for the great video Steve!

[@larsalfredhenrikstahlin8012]

same!!!!!!!!

[@guyincognito.]

The teachers probably didn't understand it.

[@donoimdono4868]

GuyIncognito - that is likely much more accurate than most would believe. if refraction principle weren't fully explained to them in college, they wouldn't be able to explain it to the next generations either. have fun explaining fresnel lenses to people when the need arises

[@official-obama]

@@donoimdono4868 humanity has devolved to the point where we need the refraction principle to understand how fresnel lenses work

[@lewismassie]

As someone who has been taught X-ray crystallography in university, this was way easier to understand

[@joeyknight8272]

Noce

[@konradkodzinski3027]

Cool, any fun facts about crystallography?

[@DG-xg8vg]

Same

[@excitableboy7031]

Ha! Nerd! I know it cos i took two semesters of physics in college

[@ChaosAT]

University is a tool to make people dumber used since Austrian kingdom to determine the best slaves in all of her lands, to fight for chicks and their bones.

[@garybarbourii8274]

This might be the highest quality video I've ever seen on KZbin. It's not often that my curiosity is genuinely satisfied by a video. It was brief, yet informative. Direct, yet it managed to inspire. The imagery was fresh and wonderful. I left without the slightest hint of disappointment. Great job man.

[@idontwantahandlethough]

Right?! All these amazing teachers on KZbin make me a little hopeful for the future, despite everything else. I think there's going to be a lot more kids that are go into science/math careers because of people like Steve and Matt Parker and all the others.

[@AverytheCubanAmerican]

Don't smash the light bulb, I need it when I come up with ideas

[@erlendse]

And they are kinda rare at some places (banned, to make more efficient stuff take over)!

[@paulclark7658]

It's alright, it was my light bulb and my ideas have converted to LED's

[@thebloxxer22]

"Don't shake the lightbulb!" - Sergeant Johnson

[@SigSelect]

Its easy to spot a KZbin video that does all the things you don't want, but when one comes along that does everything right, it sails over so smoothly you forget to notice how good it is. When I got halfway through and didn't notice my usual complaints floating up I realized I should let you know that this is a fantastic video.

[@TheHookUp]

Steve - As a full time biology teacher and a part time KZbinr I find your videos to be absolutely incredible and inspiring. Thanks for the wonderful content!

[@cyrilio]

Wow. I never understood how the original image proved the helix structure. Thanks for blowing my mind.

[@ExcludedLayman]

6:04 If you look closely at the filament, you can see it's a smaller radius helix twisted into a larger one.

[@UCreations]

exactly. And probably that smaller helix is more in the same ballpark as the wavelength of the red laser to create the diffraction pattern.

[@IDoNotLikeHandlesOnYT]

@@UCreations But it probably doesn't stretch significantly when he changes the pattern by pulling on it

[@zwz.zdenek]

Of course. And some industrial light bulbs had an order 3 helix. But the tiny ones produce such large diffraction angles that even the order 1 maximum gets off the chart. That's why you only see interference from the large helix.

[@lukel.5815]

Yep. It’s called coiled coil

[@anarbatzoriganar]

@@lukel.5815 no, it is called SUPERCOIL >:(

[@tarunkrishnaswamy8207]

The more I see your videos, the more I see science around me

[@FolkRejected]

I majored in cell biology and molecular genetics and still didn't understand x-ray crystallography nearly as much as I now do after this video. Thank you so much for the simple explanation with a scaled up example. This is so much clearer now

[@AndrewJJ-0114]

7:57 Oh, it's a montage of Windows Media Player 9 visualisations.

[@josueliriano]

I've taken about 10 courses that discussed this topic and just now am I understanding the physics behind the X-ray crystallography experiment. Please keep sharing these wonderful videos!

[@gigglysamentz2021]

2:05 I do X-ray crystallography and this image still helped me understand it better XD

[@macronencer]

I've always wondered how that image was made, and how it could have been interpreted, but it was one of those things I hadn't got round to researching yet. You explained this perfectly, and answered all the questions I had as well. A perfect video. Thank you so much!

[@mikewilliams6025]

Amazing hair growth after the 8:00 mark.

[@AntiMatter324]

Nice catch. He is wearing the same clothes so I bet most of us didn't notice.

[@q23main]

This video took _ages_ to film😉

[@Fyrespit]

Lights off, lights on.

[@JimC]

Good catch! Some stuff on the chair has been cleared off, too.

[@SteveMould]

@@Fyrespit I'm so annoyed that I forgot to turn the lights back on for those takes!

[@SangheiliSpecOp]

4:00 "but DNA doesn't have that structure so whats going on? This is where it gets interesting" *"SO I SMASHED THIS LIGHTBULB... "*

[@JimC]

Thanks!

[@techwithvj257]

I think I understood this topic first time ever in my life... In such an easy way.. hats off to you

[@joshsampey2460]

Thank you for giving proper credit to this image! Franklin is so often overlooked and ignored in this important discovery.

[@koosnaamloos4291]

Funny how I had an exam on this the day before it was uploaded. It also amazes me that you managed to explain this without saying Fourier even once.

[@Syrange13]

Fun fact: the filament in a light bulb is actually a meta-helix. You can kinda see it at 7:21

[@motttta]

My favorite videos from you so far. This was really awesome.

[@jhyland87]

When I first saw the famous _Photo 51,_ I had to research x-ray crystallography a bit, and while I felt like I understood the typical examples and patterns, I never could wrap my head around how the dotted X pattern in photo 51 was a result of the double helical structure of DNA. This video definitely cleared that up. Great video!

[@SudaNIm103]

Excellent video, I've not seen this analogy before! Your explanation answered some key questions about the famous Franklin crystallograph I've wondered about and never fully understood.

[@SudaNIm103]

Pyrophury Historical PopSci is a clustered mythos; Perhaps you can recommend an accessible resource with a definitive account of the subject? I've come across differing account most are either quite technical and make broad attributions or generally skip the details entirely.

[@lintonatlas8933]

Thanks

[@claytonbonser7629]

Look closely at the filament at 7:25. You will see evidence of a double helix. Not like the structure of DNA though. Tungsten wire is rolled up into a tight spiral, and then the tight spiral is rolled into a looser one. Quite a feat of engineering in itself.

[@63M1N1]

we're happy for you and your channel, too, steve

[@giovannil.baraldi2038]

Hi Steve, just an addendum: You can actually convert the diffraction pattern you see into an actual image of the filament. It's called coherent diffraction imaging, and its used to generate phase (refractive index) image of objects with visible, xray, electrons, etc. It doesnt work very well with fully periodic objects like a crystal, but it may work in the light bulb filament.

[@bobcunningham6953]

I know the math behind deciphering X-Ray crystallography images, and can use the tools. But no way could I ever provide as cogent an explanation of what is actually going on as you did in 10 brief minutes. Very well done, and congratulations!

[@gibbeldon]

That shot on the filament with this smooth focus transition was on spot. Really well done!

[@raymondmucklow3793]

I dig you cover things I'd never think of, not in a million years. That's why I like your channel. Cheers?

[@nrdesign1991]

I remember those old keychain laser pointers from the early 2000's, they came with all kinds of tips that produced images, including stars, patterns, cubes, and even naked ladies (although, just an outline sketch)

[@ianmburke]

Such a beautifully brilliant explanation of something so highly complicated! Amazing work

[@gigglysamentz2021]

Where the analogy breaks down is also that the position of the spots does not give any information on the molecule, but only on the way the molecules are arranged in the crystal. It's the "size" of the spots that tells you about the electron density of the molecule.

[@Leonardokite]

Nice job of explaining x-ray crystallography. You made the concept seem simple. The best type of teaching!

[@omaralessa8598]

this has become my favorite edu channel and I've seen a lot but Steve has the perfect balance of advanced concepts with simple explanations. Fantastic speaking too, I could show this to my father whose english isn't great and he can still follow along.

[@WhoLocke]

So glad you made sure to give Rosalind Franklin credit for the production of the image. Many biology students in the past were taught that it was Watson and Crick that made the image. Great video!

[@zakisaad7820]

But he didnt give credit to Raymond Gosling...he took the photo 51

[@MilesEques]

I think Steve's secret ingredient might be his in-depth exploration of the interesting ways in which his analogies break down -- something I don't think I've seen any other educator do but that goes a long way to illuminating the subject matter.

[@NthMetalValorium]

I saw that closeup of the filament like 5 mins in and I was thinking "is he gonna do it? is he gonna focus the further part of the filament?" and he did. Wonderful.

[@nobodynemoq]

Steve, you are really amazing! So many complex things become quite easy once you explain it. And with your sense of humour your videos become so much entertaining that I simply love it when you release anything new 👍

[@Broken_robot1986]

I didn't know that that x-ray crystallography was the method used to discover that DNA was a double helix. Always heard Francis' and Crick's story and knew that they already knew that the molecules make a double helix, and never once considered HOW they knew that, to know what they were looking for. Learning how the first person(s) learned is endlessly fascinating. On top of this you also convey the way that x-ray crystallography works in a way so that I feel I actually understand it for the first time in my life. Terrific work, Bravo!

[@abrumm87]

Great video! One small point of clarification, xrays can still “see” the atoms in the hydrogen bonding bases, but the phosphorus atoms in the backbone, having many more electrons, are much easier to “see” and thus easier base a structure off of.

[@wangdydu]

May I ask why duplex might cause some dots to disappear?

[@snabbott]

I went to graduate school for biochemistry (and DNA is my favorite molecule). This is by far the most accessible explanation of x-ray crystallography I have ever heard!

[@OzAndyify]

Beautiful explanation! I'd always wondered how the X showed a double helix. (The focus change was brilliant.)

[@jeremystanger1711]

So much is great about this channel. Your ideas are unique, you do fascinating experiments, you actually know what you're talking about (rather than just regurgitating an article from new scientist), and to top it all off, you've got a great sense of humour! Keep up the good work!

[@molipix]

I sat through a few X ray crystallography lectures at university and found it to be the driest topic ever. You've done an amazing job of bringing it to life.

[@WhySoitanly]

Steve Mould gets about 7 grand a month for his YT videos, and he clearly deserves it. Lots of effort in his presentations.

[@SaquibFaisal]

Steve Moulds and Science Asylum guy has one of the most underrated channels on YT.

[@whodecidedthat9540]

It's awesome to see so many people as impressed with Steve's teaching ability as me. He breaks down difficult science into easy to digest bits. Hes like Startrek but real.

[@jonhattanrai]

Your videos are real quality stuff. Thanks for making them and for making them this good.

[@fastandFourier]

I've been doing X-ray crystallography since 8 years and I find the explanation using the light bulb filament brilliant! P.S.: The point regarding the P atoms is not accurate, I hope my explanation can clarify why. X-rays are diffracted by electron density, which makes heavier elements contributing more to the patterns. True, P is heavier than O or N or C, but considering the overall structure, P is not at all a dominant contribution to the overall electron density in DNA. In reality, the effect of the DNA bases can be recognised: they are aligned forming a ladder of parallel "sheets", which would create an oscillation of the diffracted intensities along the long axis of DNA. This oscillation is present in the pattern, while the DNA chain backbone made of mostly P and O creates the diagonal features. The resulting pattern can be seen as an "interference" between the two effects. If C, N and O would be transparent to X-rays, the entire pharmaceutical industry, for instance, which makes a daily use of X-ray crystallography to determine the structure of drugs, wouldn't exist as we know it :)

[@yesthatsam]

Thanks so much for this episode : i have always wondered how that image could led to the double helix structure confirmation and always found quite obscure answers. You shed a brilliant light over that question. A coherent one that is ;) thank you so much !

[@ploxagote]

you explain things very well so props for that 😊😊

[@AlexDainisPhD]

I've never seen such a clear and amazing explanation of this. Awesome!

[@federicon.5085]

oh my god, you made the concept of x-ray christalography soooooo simlpe to understand! I never got to see DNA from Photo 51, I didn't get it before... thank you soooo much!!!

[@electronic7979]

Helpful information

[@scellyyt]

3:33 this looks like a surface with a moving camera around it but the surface is covered in dots

[@SteveMould]

Oh yeah!

[@clownshoesmma6249]

Can’t wait to see this channel with millions of subs! This channel is amazing

[@locktite401]

Fantastic explanation of the X-ray diffraction. I didn't understand before this.

[@CarJul666]

Thanks for the explanation. I've been wondering about these DNA x-rays. They confused me.

[@carpo719]

Thanks Steve. Enjoying your channel, appreciate your efforts

[@ZoZo-ub5uw]

Steve I've gotta say I'm incredibly thankful for these videos, you make hard to access scientific topics fun and easy to understand. Even I as a non native english speaker could understand this!

[@jonnyreverb]

This is really good. I taught Holography, and it took months to walk the class through diffraction. It's not easy to describe to someone for the first time.

[@sideswipebl]

Huge respect for using the wehi cgi videos. Some of the best animations of cell functions out there.

[@aaroncole3753]

I took a graduate level chemistry class and we had an entire unit on this X-Ray Crystallography. It wasn't until I saw this video that it made real sense though! I wish professors used more intuitive ways of demonstrating concepts rather than using mathematical proofs. I never saw anything like this but just tons and tons of equations. Thanks Steve for translating these amazing concepts into something more intuitive!

[@ChrisWalshZX]

Thanks Steve, I always wondered how they deducted the structure of DNA from that iconic picture. Excellent demo with red laser light and bulb filament!

[@alessi4249]

I really like the animations! Did make my eyes go a bit funny but they were a good visualisation. Great vid

[@bennynielsen1412]

I have been trying to recreate the laser and mirror making sound patterens. Your enthusiasm continue to amaze and inspire me. Thank you. Benny, a big fan in Denmark.

[@hrithik256]

0:49 GEEZ! I thought those were your fingers!

[@vivimannequin]

😂

[@Diesel257]

Same

[@simonbrowning5423]

I’m telling all my friends. Always wondered,, and assumed there were too many levels of understanding for me to get it. Thank you.

[@GlitchyfrogMusic]

I asked my teacher, years ago, if its difficult to develope a molecule. I didnt believed him till I saw your video hahaha holy moly, they did a increddible job! Nice video!

[@Tahoza]

I've been a big fan and subscriber for a long time. You deserve more subscriptions and views. I wish there were an easier way for educators to grow their channels.

[@iouliosp.1821]

The quality of this video is on another level!

[@mikecauser]

It's impossible not to click your videos Steve with such alluring titles

[@Nilguiri]

I've always been fascinated by that image and wondered how they sussed out the double helix from it. You explained it really well... Fantastic! Thanks.

[@ComplexVariables]

Awesome explanation,; I knew some of the history and have seen the pictures, but never had all the holes filed and explanation of how the pictures imply double helix. Great work!

[@KG808]

I loved this phenomena and how you explained the whole thing. You really encourage science and curiosity. Thank you

[@Eidolon2003]

My god, the rack focus at 4:40 is so good!

[@sonalmundhra248]

What an amazing explanation. Finally, I understood.

[@massimookissed1023]

4:43 I'd like to take a moment to appreciate that focus pull, on an object that's really small to begin with.

[@SteveMould]

My camera has a feature where you can set two focus points and it will pull between them over a time interval you choose. It's really nice! Panasonic GH5 by the way.

[@massimookissed1023]

Nice. That's the kind of shot Hollywood spends ages setting up with tape measures and physical stops on the focus. I've also been impressed by focus pulls in South Park and Family Guy, which are 2D cartoons(!) I assume they selectively blur parts of the shot in post production.

[@JamesChurchill]

@@massimookissed1023South Park's secret is that apart from the original short which was paper cutouts and stop motion, their animation process is all done in 3d software tools. It's how they're able to produce content so quickly, and it makes special effects a lot easier.

[@massimookissed1023]

@@JamesChurchill , yeah, South Park use Maya, so they could probably use Z-buffer depth data to inform a focus effect. In "A Very Crappy Christmas" the kids make an animated movie the same way Matt & Trey made the first episode, highlighting the grief of just animating lip-sync. Family Guy though is hand drawn¹(!) ¹In the DVD commentary, (which is well worth listening to on Family Guy, (and The Simpsons)) there was mention of computer 3D modelling used to animate a car turning. The CGI wireframe of the car was then hand traced and animated as usual. They said "Koreans can't draw cars."

[@XetXetable]

That photo wasn't made by Rosalind Franklin. It was made by Raymond Gosling, who was under Rosalind Franklin as a student at the time. The photo was published in "The structure of sodium thymonucleate fibres. I. The influence of water content", which has both Rosalind Franklin and Raymond Gosling as authors. I think it's pretty ironic how many stories are made about Franklin being a "forgotten heroine of science" whose work was stolen by men when the most famous photo attributed to her was taken by one of her male students who seems to have genuinely been forgotten.

[@frgmntTOB]

Excellent demonstation of this analogue behaviour!

[@MrHellishghost]

Looks like Steve has studied and learned so much from different subjects, that he unblocked the "teach anything like 2+2=4" skill on his brain! Amazing video, man! You're a inspiration!

[@omsingharjit]

5:25 ok then What about this scenario . When you are doing experiment with red laser with tungsten bulb's coil? Distance between coil gaps not seems anywhere near of wavelength of red light ?~

[@zenvir1680]

Fun Fact: The coil of light bulb filament is made of a yet another tighter coil, so the thickness of the tungsten wire used is about 1/20mm

[@oseqq]

Great topic. And so well explained step by step.

[@YossiSirote]

Thank you for this video!! I had always wondered exactly what you explained!!

[@Micetticat]

Wow! Amazing graphics and camera work for this video!

[@AdrianaTufaile]

Last week my class experiment with visible light diffraction in slits and diffraction grating. In today's class a student (Carolina) asked me how can we link what we saw with the DNA image made by Rosalind Franklin. So, I indicated this wonderful video. We saw the beginning of the video in class and I bet Carolina is watching this video now. We are in São Paulo, Brazil.😀😁

[@winproduction7585]

Best explanation found on youtube!

[@mdestwo]

Fascinatingly clear video. Thank you. One thing I’m wondering now, though, is what Skillshare did with the first four Steve Moulds.

[@SteveMould]

They take a backup of the previous Steven Mould's brain and upload it to the new one so I'm basically the same person.

[@triPocoPi9576]

Why is this video two years old and hardly anybody’s watched it. It’s a great video

[@timobatana6705]

Thank you Steve! You are a good man. Keep teaching about these concepts its awesome

[@Jmjholden]

Steve I love this video so much. Makes it so intuitive and I wish I had this video years ago

[@michaelhunter5510]

I think there is a smaller coil within the bigger coil (if you look closely, the strand of filament within the coil is actually itself a small coil). Since red light has a wavelength of 620nm, probably it’s the smaller coil that’s causing the diffraction pattern.

[@zyzzbodybuilding]

You got some mad videography and steller editing skills. Keep up mate