r/Veritasium

The recent video made it obvious to me that it is AI generating the voice, so sad but the guy did say he was leaving

After watching the Veritasium video about the Copenhagen interpretation, I thought about reading the book What is Real written by the guy that was being interviewed on the video. I saw many comments saying that the explanation of the copenhagen interpretation wasn't the best, and i'm not sure the book is even worth it given that i watched a 40 min video. Did anyone read the book and can tell me how it was?

Let me start by saying Veritasium is fantastic, and the latest videos are great, it shows where the new investors and the expanded team are adding value. Huge shoutout to everyone in the team.

That said, I’m wondering it anyone else felt a bit cringy about how Casper seems to try really hard to imitate Derek’s expressions and speech?

I don’t mean to be rude or anything, just saying I’d much prefer Casper adding his own style and coming across as authentic rather than what he seems to be doing which if I’m honest is a bit off putting

Is this just me?

So, today my physics teacher, as an Xmas present allowed us to watch a video instead of a lesson. It was Veritasium's video about rainbows, which he chose himself:) It must be noted that in Russia, where I live, Derek's content is not very popular, this is why I was even more happy, watching it. Don't know why, but I really wanted to share it with you:) And sorry for bad english

I've seen a lot of negativity in this sub lately, which is quite sad considering the amount of quality content Derek has produced. With his upcoming retirement, I thought this would be a great opportunity to discuss some of his best work.

​For me, the Blue LED video easily takes the crown. It covers an incredibly important and underrated engineering breakthrough and is narrated beautifully, weaving in the story of Shuji Nakamura and his relationship with Nichia. The technical explanations are also very well done. At this point I've re watched it multiple times with different people and I just don't get tired of it.

​My other two favorites are "What Everyone Gets Wrong About Gravity" and "What They (Probably) Don't Teach You About Rainbows."

Note that I don't know if these are technically accurate videos but I just enjoy them a lot (I hope they are 😅)

What are yours and why?

I don't know what to say, i am sad that i am not going to be seeing Derek as often anymore, i was always entertained while watching his videos as a kid. And right now i don't like where this is going with Vertasium. What do you think?

I'm assuming I'm missing something, because this seems too simple to be "the solution" but I can't figure out where the "hidden other direction" would be.

Imagine you have a disk one meter wide with a 1 mm channel passing through it. On one side you have a continuous light source shining on the edge of the disc. On the other side, you have a light sensor that will detect any light passing through the channel. You spin the disc at an increasing rate until no light passes through. (My math says 5.7 million RPM.) You don't care how long the light travels between the source and the disc, and you don't care how long it travels from the disc to the sensor or how long the electrical signals of the sensor take to register. You can use my leg to measure the diameter so even that isn't based on speed of light if you really want to and we'll figure out light speed legs-per-second. I'm guessing that there is a fuzziness as you approach the proper speed, where light could enter the groove before it is fully open and manage to exit properly just as the groove lines up, but I assume a professional could work out that math.

So discounting that we don't have a motor that can spin a small disc that fast, much less a 1 meter one, and I don't know if any material would stand spinning that fast anyway, is there any hidden other direction of light travel that I am implicitly calculating that I am missing?

And would the rotating disc warp space-time enough to screw it all up, or something like that?

Maybe the opposite system would also work, where a spiral-ish groove is cut in the disc and the speed increased until light is seen, meaning that the disc is spinning at just the right speed that a few photons of light can enter the groove and travel in a straight line as the spiral moves around them.

If only the physical limitations of such a high-speed rotation keep this from working, what about 100 discs with edge indexing. Between each pair, you install a synchronizer whose only job is to make sure the discs rotate at the same speed so that their grooves line up. 100 discs would be 99 synchronizers, and no electromagnetic signal is required between synchronizers. The speed of the discs would need to be set remotely, but you could hold any given speed for long enough that any signal speed weirdness is canceled out. Then I think the rotation speed would drop to 57000 RPM because the light would need to pass through all 100 meters of aligned disc in the time it takes any one disc to rotate out of alignment. I assume physical gearing would prohibit this because of speed limits and slop in the gears. Would something like a magnetic sensor in the synchronizers be able to cancel out the "one-way-ness" of the measurement?

I recently came across the video by Veritasium talking about the Principle of Least Action and in the first part, he shows that using it, u can get back Newton's Law of Motion: F = ma. He isn't the first to show this though and many other youtubers show the same result using a similar method, a few given below.

Veritasium:
Physics Explained:
World Science Festival:

The problem I have with all of them is that they all use the result that the KE of a CM system is given by K=1/2mv^2 and plug it into the equation for the action and then eventually show that it leads to F = ma.

The problem is that the formula for the classical KE is derived from F = ma.

One way is to solve the differential equation: F = ma = -dV/dr where the F = -dV/dr part is from the definition of work done.

Another way is to use its definition directly: W = Fs = mas and use the kinematic result v^2 = 2as when u = 0.

Either way F = ma is used to get KE=1/2mv^2 so it should not be a surprise at all that using it gives back the result F =ma when used in conjunction with the principle of least action. But all these videos make it seem like the principle of least action is much more powerful as F =ma can be "derived" from it when it literally uses a result from it to do so.

Isn't this circular reasoning??

Also, the fact that they all used a similar approach seems to indicate to me that they were shown this same sequence of steps somewhere which begs the question how did no one else question this "derivation"?

Would like to know other people's thoughts on this as I want to know if my concern is valid or whether I made a mistake somewhere in my reasoning. Thanks.

So in the new video, around 26:50, when they discuss hidden variable theory, they say that the particles decide what answer to give to the machine. However, according to the beginning of the video, the particles only decide what spin they have, not what answer they will give to the machine. If the particles simply decide that one has positive spin and the other has negative spin, then if one is measured as positive and a machine tilted by 120 degrees is used, there should again be a 25% likelihood of disagreement, right? Why do they assume that the particles decide what answer to give to the machine when they should only be deciding the spin?
(I have 0 knowledge about quantum physics, i was just curious)

I'm also a big fan of Steve Mould, VSauce, Technology Connections, Numberfile.
I understand many of these lend themselves to video explanation but just wondering if there are any podcast suggestions that are similar. Thanks

the new Veritasium video about Bell’s theorem, and the way it talks about the Copenhagen interpretation is just wrong. The video treats Copenhagen like it’s a realist interpretation where particles have pre-existing definite values that collapse physically across space. That’s not what Copenhagen ever said.

The entire framing of Copenhagen as “nonlocal” comes from assuming something Copenhagen explicitly rejects. So the video ends up arguing against a version of QM that no one actually believes.

Copenhagen does not say particles have definite properties before measurement. In fact, this is the one thing Copenhagen is very clear about. If you measure spin on one axis, that is the only moment that value becomes meaningful. If you rotate the measurement device, you are literally defining a different observable. There is no sense in which the particle “already had” a value for every possible axis. The value is created in the measurement context.

This matters because the whole EPR argument assumes something called counterfactual definiteness. Basically, EPR says that if you can predict with certainty what a measurement result would have been, then the particle must already have had that value. Copenhagen says this assumption is just wrong. Unmeasured quantities have no value. There is no “fact of the matter” about the result of a measurement you didn’t do.

If you remove that assumption, the entire EPR “paradox” disappears. There is no need for nonlocal influence, because there was no pre-existing value to transmit in the first place.

The video also treats collapse like it is a physical event that spreads across space. But collapse in Copenhagen is not a physical signal. It’s just an update of the observer’s information. The global quantum state already encodes the correlations. Nothing travels between the particles.

Bell’s theorem also doesn’t say “Copenhagen is nonlocal.” Bell shows that you cannot have a theory that is both local and realist. Copenhagen already throws out realism. So Bell’s result doesn’t contradict Copenhagen at all. It contradicts local hidden variable theories.

The weirdest part of the video is that it treats Many Worlds as the “local” option. But Many Worlds still uses a global entangled wavefunction that doesn’t factor into local pieces. It avoids collapse, but it doesn’t give you classical locality either. Saying “many worlds is local and Copenhagen is nonlocal” is just misleading.

I’m honestly very upset that they seemingly didn’t talk to ANYBODY with any actual reasonable credentials to talk about QM in this context. It’s a very bad video, do NOT take what it says on its face, almost all of it is wrong or misleading.

also to be clear, this is just what I gathered from watching, feel free to disagree, and if u do lmk y!

I was happy to see her appear on the latest video about quantum entanglement and the EPR paper. At first I just thought she's a guest since she does quantum themed videos on her on channel. But on a second glance I saw that she's listed as Veritasium Producer, not a guest. This is interesting and raises a few questions as well. I certainly would like to see her more than other secondary producers. She already has a YouTube channel and proved that she can present things in a fun way, unlike the other 'new' faces on the show.

What are your thoughts on this?

They have gotten so boring. I am an engineer and half the explanations go over my head. Maybe i'm just dumb but I get nothing from these videos anymore.

I take my time to write this because every time entanglement is explained wrong , and other physics subs get flooded with wrong ideas.

Veritasium new video on entanglement makes the same mistake that any popular explanation of entanglement does. It makes Einstein look smart but then it shows a stupid version of EPR. The video considers that the EPR paradox as two envelopes with complementary values (+,-), when you open one envelope and get (+) you know the other envelope has the opposite value (-). However this is so bad that in the video they even show that such experiment could be explained simply with hidden cards inside the envelopes.

Einstein, Podolsky, Rosen and Bohm (from which the EPR version of the video is based) knew much better. Explaining entanglement makes no sense if you do not introduce the problem that two variables can be non complementary. Like position and momentum as used by EPR; measuring the position means that you have no idea on what its momentum is. Bohm used different components of spin, you cannot know the y and z components at the same time for example.

The point is the following, if we accept incompatible measurements, if you measure the position of one particle you already know the position of the other particle, so you can now measure the momentum of the other particle. In this case, you know both position and momentum of the two particles which is not allowed by quantum mechanics.

By avoiding this fact the EPR paradox seems very stupid and simplistic. Also it does not give a clue why entanglement is so puzzling. The need of incompatible measurements is why the Bell test measures more than one angle.

Edit:

Disclaimer I have to give to Derek various points he did extremely well:

• Derek adresses Einstein Solvay argument

• He addressed the "local realism" is not in Bell's work

• The Bell test is well explained it shows why classically we cannot explain entanglement

• He adresses that faster-than-light signaling is not possible.

Edit: when earlier I said it makes Einstein look stupid I mean it in the sense that the video makes Einstein look smart and then offers a stupid EPR experiment.

No matter how I try to get to 25% and 75%, I keep arriving at 2/9 and 7/9, which is quite close to 25% and 75% and the difference is not relevant in this experimental situation, but is decidedly a different number. Given that we're dividing a circle into thirds, I can't see how 1/4 can even enter the problem...

I've watched the channel for years, almost every video. I love the science/math/physics etc communication style videos and channels.

The thing i dont understand, and find personally annoying, is the "live person on the street" segments of the videos which seem to be becoming more common.

My question is: what is the intended purpose of these segments? from an education perspective/ filmmaker director design conceptual intent

Because i DO find them annoying, mostly as filler, but i dont really see any positive in "this random person on the street who has clearly never thought of this for more than 5s got the answer wrong". It feels weirdly condescending but also like, separating as a communictor, it feels antithetical to the notion of pedagogy and trying to teach to start by diminishing a persons self esteem by telling them they were wrong, people take that personally. I'm not saying its being done maliciously, and i dont think the people on the street SHOULD take it that way, but those are facts of human minds that we aren't perfectly rational. My issue is that this seems to be being done more and more often, and i think displays a lack of foresight about how it will be received both in person individually and on the audience, and a lack of cognitive awareness.

my BEST GUESS is that its meant to show "look, audience on youtube, getting this wrong is okay, its common for people to get it wrong" as a way to soften the "blow" to the ego of the viewer and as a hook to get them to continue watching to now see what the correct answer is. but this seems like a very poor methodology to go about doing it and it does not come off positively imo, almost every video would be better without it.

I mostly want to try to understand, usually if i can understand the reason for something i can lower my personal annoyance and tolerate things better, but here i am struggling to find that understanding.

I've seen some recent comments here on various threads as well as and claiming that the simulations shown on videos and attributed to Casper are either AI-built or outsourced to web dev companies.

I'm a web dev with a physics background and I see no reason to assume that a dude like Casper would be unable to produce these apps or even a lot more polished ones, since the component libraries and frontend frameworks provides a lot of help with all of that. I decided to review the apps and while I obviously can't prove Casper was the one making them

TL;DR: I am fairly certain the apps are not made by AI and are made by someone with a science background.

I skimmed over the sources of these simulations:

Some of my observations:

• All the logic is inside a single file. THE single file. The HTML itself contains raw JS. No bundling and minification, no component libraries, no d3 or anything fancy.

• The code is extremely procedural. Huge amount of let variables. The functions are used, but just a few are pure functions (i.e. functions in a mathematical sense that map input to output), most of them are just procedures of the doThing() type the change the global state of the app.

• The code is organized by types, e.g. "element references", "event listeners" and so on.

• The comments are written in a mess of styles, some comments try to act like headings with funky // ================== and // --- SECTION 4: COR.. lines --- they are used as code organiation tools. Comments are written in a variety of styles and formattings.

• Some of the comments in CSS explain selectors and what the rules do although all of that would be perceived as self-documenting by a professional dev. The JS comments redundantly repeat what the name of the function documents.

• They even have the comments NEW, MODIFIED, REMOVED hinting at lack of version control.

All of these are things that a professional web developer would do differently. Most of these things are not something that AI would ever suggest or provide. All of these patterns are common in code written by science people. Sure, some individual functions might be copied from examples, but that's something we all do. I would suspect the author didn't even use "properly" configured IDE.

The overall architecture and formatting seems such that would be very commonly found in science circles. It looks like the JavaScript that I wrote in 2011 while slowly switching from doing fluid mechanics' simulations in C to interactive apps on web.

Final words: It's fine to express dicontent with the direction of the channel, call out the flaws, feel disconnected and just complain, but let's not make unnecessary and ungrounded accusations of dishonesty.

The title of this post probably sounds kinda antagonistic and negative, but I don't mean it to be - what I really want this to be is an explanation of why I've been feeling a bit distant and disconnected from the new Veritasium videos. I've been watching the channel for over a decade, but the recent shift into having multiple hosts has felt a bit... cynical? I'm not going to pretend I haven't seen the video revealing the whole private equity status, but other channels I enjoy watching that were 'exposed' in that video haven't had this marked shift in personality over the last year or two like Veritasium has (and tbh, I've been thinking this since even before I saw that video).

I really don't want this to come across as criticism of Casper or Henry, but their presence in recent videos feels really _forced_, or maybe a better way of putting it would be calling it unearned? I don't doubt that either of them have been a presense behind the scenes for a while, but the way that they are now (completely out of nowhere) center-stage figures in the video feels very jarring. This isn't your usual ha-this-guy-seems-endearing-I-wish-we'd-see-him-in-more-videos, it's just a... new guy who's now the centerpiece for the video. We haven't even seen a good reason why these guys have earned their place for being in front of the camera, yes they can interview guests over a zoom call or do Derek's old street interviews, but there's nothing that's intrinsically _them_. It just feels like if this were some organic thing, it would be some other youtube creator that would be shouted out - like those other channels were in the classic electricity or wind-powered-car debacles - and eventually naturally folded in to the channel. Like a collab that just fit so naturally, it would feel silly not to bring them in.

To illustrate my pont, the whole 'here's a simulation so-and-so built to demonstrate the topic of this video' feels _so_ forced, they clearly just outsourced it to another company/AI and now they're getting one of their new team to put a face on it to get them more exposure. It just feels really cynical and unearned. If in an old video you'd seen Derek say 'here's a simulation I built', it would be some strange looking thing that looked clunky but got the point across, but now it's always a clean, polished, coherent UI with toggles and modes and nice graphics and we're supposed to believe it's one of your writers that made it? Just say you got it commissioned, there should be enough to your co-hosts that you don't need to falsely attribute things to them.

I love the amount of content we're getting for the last year+, and the quality and topics are top-notch and we're very lucky to have them, but I just wish there was still the 'yesss another Veritasium video' feeling when I see a video, rather than just a 'oh there's another Veritasium video with X or Y'. I don't expect Derek, or the old Veritasium, to be around forever - I just wish the new was as earned as the old.

Hi everyone. I’m an otr tire tech and I’ve gotten into an argument with coworkers about a physic problem. say we have two tires of the same size (57 inch) one of them is filled with air (100 psi) and the other one is partially filled with calcium (85%) and the remaining 15% is air (100 psi).

which one is more deadly?

I've tried using ai to get the truth but I’m getting mixed answers.

Out of ideas, not sure how to make an experiment.

I thought about veritasium to maybe get a clear answer.

Thank you.

EDIT: it's likely they DID NOT use AI for the simulations, i just made an assumption off the generic css. either way it doesnt matter, the simulations are pretty cool and you should have fun screwing around with them

the simulations are cool dont get me wrong but its pretty funny when he discusses his team building a software simulation when the simulations look like they were one shotted by some tool that instant deploys to web, like v0 or something.

i really dont care tbh, im a software engineer and pretty much everyone uses ai at this point anyways, but found it interesting that nobody really noticed it.

Hey y'all. I'll keep this short. thought it would be best to share this here since its a subreddit about the Veritasium channel. its been so great to watch the videos they have been posting lately. I have learned so much, their docs style storytelling along with the animation makes it super easy and fun to understand. my mind gets blown away every single time I watch the videos. does anyone feel the same way. I am inspired by this channel to go and learn more about the history and technology we have. It often goes unacknowledged and Veritasium is one of the few channels that does this sort of thing. bring niche/unappreciated technological advancements and putting the spotlight on it, displaying how it impacts our everyday life.

its been great watching the videos and need more of it. so if anyone got other channel suggestions that do something similar or maybe an online community where I can talk to individuals like the ppl who produce the Veritasium videos I be really interested in getting in contact.

I don't know exactly when private equity took over but the more recent videos feel off and even a bit soulless. The format has also changed a bit and can easily be summarized (I feel like):

Derek: Hi, I’m Derek and here’s a strange phenomenon/interesting science subject that occurs often but still many people aren’t familiar with.

Casper: Hi, I’m a tall Dutch blond guy or something.

Derek: Hey tall Dutch blond guy, please provide me with a simulation about ‘interesting science subject’ while you explain how it works and do interviews with smart people.

Casper: *runs simulation and interviews people*  

Derek: And that’s why numbers do strange things and technology is the way it is.

Don’t get me wrong, I like his videos but they don’t feel the same anymore. They’re still interesting with a high quality production value but something feels off.

I am relatively new to this channel. I have immensely enjoyed many of his videos, but honestly the constant title and thumbnail changing is a huge turn-off for me. I understand the desire for more engagement, which can be a nice counter argument to my feelings (because maybe I wouldn't have even come across the channel if it weren't for the constant change). But I really can't shake the constant changes in my own mind, it seems so fake for a channel named "veritasium" after all.

to be clear, I understand the reasoning, but it's a hard mental barrier to accept and still fully appreciate the channel, at least at the subconscious emotional level.

On, a practical level, I totally didn't realize this was happening when I first came across the channel, because I thought I was going crazy unable to find a video I had seen in my recommendations...

In Veritasium's video "", he presented some people on the street with a problem about the efficacy of a hypothetical face cream, which required an understanding of proportions to solve, and others with a similar problem using the same numbers but reworded to be about gun control. There were two versions of each problem, with the numbers either supporting or opposing the effectiveness of the face cream or gun control laws.

The conclusion was that, while the likelihood of getting the question right was proportional to numeracy when the problem involved face cream, accuracy didn't increase—and even slightly decreased—among higher numeracy levels when the issue was about gun control.

The problem I have with this is that the accuracy wasn't dipping because the minds of the ignorant sheeple were hopelessly brainwashed to the point that they refused to sway even in the face of damning evidence. The accuracy was dipping because rewording the problem to be about gun control engaged viewers’ prior knowledge in a way that face cream and skin rashes did not.

Consider this problem:

Is it worth paying $1,000 for a small but non-zero chance of receiving effectively infinite money?

Any rational person would say yes. But present the same person with Pascal's wager, and they are likely to get the "wrong" answer, despite the problem being nearly identical.

Or consider an even simpler problem that makes the issue blatantly obvious:

It took Marie ten minutes to fold two paper cranes. If she works just as fast, how long will it take for her to fold three more paper cranes?

The answer is clearly 15 minutes. Now, "reword" the problem like so:

It took Marie 10 minutes to saw a board into two pieces. If she works just as fast, how long will it take for her to saw another board into three pieces?

Now, the attentive viewer who correctly objects to using the same method to solve this problem (which uses the exact same numbers) and gives the answer "20 minutes" is, Veritasium would argue, the narrow-minded fool who let their opinions on the matter (i.e., common sense) get the better of them.

My point is that the moral of the story is not that people's opinions skew their ability to reason, but that context is important when considering problems. Real-life issues are not tidy word problems. Conflict arises not because people are irrational tribalists and one side is just wrong but won't admit it, but because different sides have different facts because of failures in communication, and even on the same facts, there are different interpretations.

I'm sure he's discussed how his style has evolved, and that he recognises how the best thing is to put the punchline first. I'm pretty sure he deconstructed , and said it was boring and slow and that he should have opened with the cool demo of hitting it on the counter top and watching the ice spread.

All I can find now is a short clip about it in 'My Life Story' - but if I had to bet, I'd say he's just used that clip twice in two different reflective videos.

Please help!

In his latest video, Derek showed the right way to tie a shoelace is by going clockwise instead of counterclockwise as this creates a square-knot which is much more stable than a granny-knot.

But this got me thinking that can't be the only way to do this and I think I was right. You can still tie a square-knot by going counterclockwise. This is because tying a shoelace knot is a two-step process. If you invert the first knot, then you need to go counterclockwise for the second knot to make it a square-knot.

Found a video explaining this too:

Preamble (feel free to skip)

Firstly, I would like to apologise for posting a topic like this; I have read through many of the "Is this the solution to the one-way speed of light?" threads already posted on this subreddit and have seen the comments gradually growing more exasperated at having to deal with yet another thread about this, so I would like to say sorry for adding to that. I promise that, if I was smart enough to figure out myself why this wouldn't work, then I wouldn't post it here.

Secondly, I would like to clarify that I don't think that this is a solution. I have posted it here because the people here seem to be better-educated than me and have a more indepth knowledge of the physics surrounding the problem, and so would be more likely to help me understand why this wouldn't work, if that makes sense?

Thirdly, this doesn't contain a way to measure the one-way speed of light, just an attempt to try and determine if there is a discrepancy in the one-way speed of light in different directions. (See point 6 below)

The Problem™ (or my understanding of it)

In the video that Veritasium posted, he set up a hypothetical scenario, within which there were some guidelines on what is possible within this hypothetical scenario:

(1) There is a way to fire a laser over 1km of perfect vacuum

1:47 - "Imagine you have a laser that can fire a beam through a perfect vacuum for 1km."

(2) Electronics that are "together" can be synced perfectly.

2:42 - "Start with the clocks together and sync them up first."

(3) Clocks can react instantaneously to the presence of laser light:

1:53 - "Start a timer the instant you fire the laser beam, and then, exactly when it hits the end, stop the clock."

2:08 - "OK, so you need two clocks: one at the laser and one at the end which stops automatically when it detects the laser light."

There are also guidelines on what is not possible within this hypothetical scenario:

(4) Electronics cannot be synced "remotely"/at a distance.

2:19 - "You could connect them via a wire and send a pulse from one to the other, but that pulse will travel at the speed of light so it will arrive with a time delay."

(5) Electronics that move relative to one-another are no longer synced.

2:53 - "The clock at the finish line was moving with respect to the one at the start, and special relativity tells us: moving clocks tick slow relative to stationary observers."

10:42 - "How about starting with synchronised clocks in the middle and moving them apart with equal and opposite speeds? [...] This only works if the speed of light in each direction is the same; if the speed of light depends on direction, then so does time dilation."

Finally, there is the question being posed:

(6) The broader question is whether or not you could figure out there was a discrepancy in the one-way speed of light in different directions, rather than what the one-way speed of light is in a given direction:

4:21 - "What if the speed of light in this direction is from the speed of light in this direction?" 4:33 - "The question is: could you figure it out?"

Therefore, any "solution" proposed should be compatible with these guidelines.

I acknowledge that some of these are impractical (like a km of perfect vacuum) or otherwise not actually possible (such as the "instantaneous reaction" of clocks, etc.), and their impact on any actual measurements in the real world might be more than negligible (although I'm not sure to what degree this is true).

Some thoughts on a possible "solution"

(Credit to Veritasium for the graphics!)

On the "start" end of the 1km stretch, there is a pair of lasers:

• The lasers are identical in specification.

• They are positioned alongside one-another, with their beams parallel to one another.

• The lasers are synced to fire their beams at exactly the same instant.

• The lasers, once synced, are not moved with respect to one-another.

At the "finish" end of the 1km stretch, there is a pair of clocks/timers:

• The timers are identical in specification.

• The timers can react instantaneously in the presence of laser light.

• The timers are positioned alongside one-another and are lined up to match the two lasers 1km away.

• The timers are synced so that their clock measurements are identical.

• The timers, once synced, are not moved with respect to one-another.

In the 1km stretch itself:

• The stretch is exactly 1km.

• As in the video, there is a perfect vacuum between the laser and the timer, and this remains the case for the first of the two laser beams.

• For the second laser beam, rather than a vacuum, there is a medium placed inbetween the laser and the timer:

• The refractive index of the medium is greater than one.

• The medium is flawlessly homogenous, giving it a constant refractive index along its length.

• The laser is lined up with the medium in such a way that the angle of incidence/refraction is 0° (such that the path the laser follows is the same as if the medium were not there).

Finally, for the complete setup:

• It has 3DoF (can be rotated/reoriented freely in space).

• It can be locked securely into any orientation selected for the duration of the experiment.

The experiment would then be to fire both lasers, note the time difference between the two timers, then repeat in different direction(s) to see if the time difference is the same across all of them or not.

NOTE: This is based solely on my understanding that the speed of light through a medium is a fixed fraction of the speed of light through a vacuum in that direction (e.g. for a medium with a refractive index of 2, the speed of light through the medium would be half the speed in a vacuum). This may be entirely incorrect.

Examples:

For these examples, the refractive index of the medium is 2.

: In the case where the speed of light in a vacuum in the measured direction is c, the time difference measured would be 3,335.641 ns

: In the case where the speed of light in a vacuum in the measured direction is 0.8c, the time difference measured would be 4,167.008 ns

: In the case where the speed of light in a vacuum in the measured direction is 1.2c, the time difference measured would be 2,779.805 ns

Basically, if there is a difference in the speed of light between two given directions, then there should be a difference in the time difference measured between the two timers in each of the directions.

This solution has been stuck in my head for about a year now and I can't think of a reason why it wouldn't work (outside of the practical stuff like constructing a 1km freely-rotating perfect vacuum chamber, etc.), so I have decided to post it so that I can find out why it won't work and free up the part of my brain that's been occupied by this solution.

TL;DR:

Shoot two synchronised lasers parallel to one-another simultaneously -- one across a vacuum and the other through a medium -- towards two synchronised timers and measure the difference in time it takes for the two beams to arrive at the timers. Reorient the whole setup and repeat. If there's a disparity, it may be due to differences in the speed of light in different directions. If not, then I guess the speed of light is the same in the two directions?

In he adds "Deliberate practice" to the list. I remember there was an older video by him about this topic as well, and it only had 3. So what makes him add the new one? Which research is this?

what are the ways yo make the water to water vaper in seconds..... I need serious answers please..... I need something that actually makes the water to vaporize in seconds efficiently

I just watched the video about the intermediate axis theorem, and I was wondering if maybe the reason Uranus spins on its side has something to do with this? Like maybe Uranus was once spinning in the same way all the other planets are spinning, but then since it had an oblong shape or a comet hit it or something similar happened that upset its rotation, so it flipped onto its side? Or maybe only the outer layer(s) are spinning sideways and the inside is spinning a different way? Correct me if I'm wrong!

Sorry if this has already been covered, tried searching but got nothing.

Double-slit interference experiments have been done around the world probably thousands upon thousands times. If the speed of light differs depending on its direction, wouldn't that show in the interference patterns? I think its established that frequency of light doesn't change with direction so if the frequency stays the same but the wave moves faster or slower, the pattern would change. I presume some of those experiments are/were precise enough to spot if there was anything to this.
Or as I'm just an armchair scientist, I have no idea what I'm talking about. Just had to get this off my chest.

Hello, I’m looking for one of Derek’s video where he’s talking about events happening in the brain, trying to rationalize intelligence. I believe he was talking about dark matter & the interactions that might give randomness (maybe?) that allows for greater understanding/intelligence aka, being smart. Would love to watch this again, thank you!

Is it in my head, or has this been discussed. Now, I'm not saying Derek is seeing months ahead in scheduling and making his videos to coincide with releases, but I think maybe some other channels put out/re-upload old content or legacy content based on Derek's videos.

For instance, a 2 days ago Derek released the magent video, a few hours ago BBC Earth channel released a video calle "Strongest Magnet In the Universe:"

I just feel I see little coincidences like this all the time, and of those times it's generally veritasium.

This question is in reference to the video, the stickiest *non-sticky* material.

The concept of gecko tape explains the grip of geckos on the vertical wall, but how do geckos stick on the roof?

Shouldn't they fall of the ceiling just like the tape did?

Okay, regarding , help me out a bit:

What if... you had a 2-light-year circuit. On your end there is a battery, a light, and a switch. One light year away at the other end of the circuit, there is another switch and a person who can close or open the circuit at will.

I get that you can't break causality, so when you flip your switch and close your part of the circuit:

1. does the light always turn on for at least a year?

2. does the light always stay off for at least a year, or...

3. does the light respond immediately to whatever the state of the other switch was exactly one year ago?

4. Something else?

It's been almost a year, and this question is still keeping me up at night. Like a light. That won't turn off. Or on. For a year.

This is one of many posts about the one way speed of light video, so I'm aware I'm stepping on well-trod ground here, but after some minutes of searching I didn't find any posts about the Doppler effect and red shift so I wanted to share some thoughts here.

The concept at hand here is that I believe the Doppler effect would be affected by the directionality in the speed of light. In the extreme example where the speed of light is instantaneous in one direction, according to my understanding, there would be no observable Doppler shift. Thus, if the directionality of the imbalance in speed of light were constant, we should see some asymmetry in red and blue shift in astronomical measurements, and possibly in the cosmic background radiation. Is there a subtler argument that I am missing? If not, what prevents experiments being done which bound differences in the one-way speed of light based on Doppler shifts in different directions?

I remember seeing this as a kid and loving how it locked, as an adult I still find it interesting for the ingenuity this took.
I looked around for a video to explain this in depth, theres a video or two explaining this ()

from what I've gathered, it basically works off of siphons (note the tall skinny tubes on the right, to the left of the minutes globes.)

Id really like a video on this- if nothing else to admire the history and the ingenuity of this and increase its publicity :P

Thanks :D

Like the title says. I could have sworn I watched a veritasium video where he discussed why there were like 5 giant sea creatures yet to be discovered by science. I thought the reason had something to do with based on the rate we've been discovering animals. Any way I'm super high and really want to show my wife this video. So if anyone know what episode or knows what I'm actually talking about that would be great. Thanks everyone!

Hello everyone, I'm new to veritasium and I've recently watched the 2 year old video. I'm confused, isn't the speed of light measured from Maxwell's equations? c=1/√μ0ε0. And I think those quantities depend on the electric and magnetic nature of the materials and not the direction. Or have I gotten it completely wrong and the permeability is measured from a two way light trip inside the materials?

This also appeared in the video: "Maths Fundamental Flaw" at 29:48

Thanks if anyone knows!

I'm looking for a video where they mentioned a professor who could determine which sequences of, for example, ABBAA... were truely random and which were created by his students. This is because humans are bad at understanding randomness and often avoid sequences like BAAAAAAA by alternating A and B like ABABABBA.

As title says, I remember long ago a video about how for far away celestial bodies, any light that they emitted that didn’t reached us up to certain threshold was seen as twinkles, due to it being impossible to be physically “fainter”. I’m looking for the video but can’t locate it. Any help is welcomed.

Hello guys! I have been looking for a CAD model for the analog wheel adder that Derek used in his video about analog computers. The little wheel thingy that turns. I wanna get my hands on some resource so i can 3d print it myself. So if anyone has it please let me know. Thanks!

After I watched the Haber video a few weeks ago I've been left with a few doubts.

Most of the Nitrogen based fertilizer is currently coming from natural gas

Seems that at the current rate we'll run out of natural gas in 52 years

Looks like a very tangible correlation is already established

So my question is: what's the plan for what will happen in 52 years?

What was the name of the Veritasium sponsor that manufactured that explorer box for children again? I think that'd be a nice gift for my brother

Thanks :)

I started writing a series on theoretical science using the human body as the subject of study. The series is set in the stone ages in a place where cutting people open is illegal. So, the protagonist is trying to figure out how the human body works with non-invasive techniques.

The first three parts of many are written so far:

I could accept some points about this, but how, for example, is it explained when a phone is charged? Is a phone charged with magnetic waves, or does the phone hold an almost constant amount of electrons which lose energy and when the battery is charged they get excited again?

From what I gathered after watching the video is that certain professionals can't achieve 'experty' because the work they do is random and isn't suitable to do the four things to become an expert. Is this correct?

I'm wondering if anyone else found the recent video "The 4 things it takes to be an expert" as being somewhat naive or short sighted potentially bordering on biased. It seems entirely reasonable to say that we "shouldn't trust experts" in fields where there isn't 1. repeated attempts with feedback, 2. environment validity, and 3. timely feedback (the 4th point is seemingly vacuously true), but this line of reasoning seems to have large gaps in normal considerations of "mastery" or "expertise" and how one would get to such a level. For example, a master composer, who might reasonably be considered a master because their novel compositions deeply reached millions, would not particularly learn to compose by writing 1000s of pieces while receiving timely and valid feedback on each one (music doesn't particularly have "valid feedback" anyways). Nonetheless, said master composer could absolutely learn from other methods, like listening to lots of music while trying to hear different music patterns, or experimenting on their own with only "self-feedback", or attempting to "understand"/play other peoples music, or learning to "find their own niche", etc. (all of which lack the first 3 criteria where the video seem to strongly suggests that even missing just 1 immediately invalidates the practice).

I personally find this kind of "reductionist" viewpoint (of seeing humans as basically just "machine learning models" that need lots of data and feedback in a valid environment), while it may be true to some extent, it is clearly not the end-all-be-all of expertise or mastery which for the most part is more of an open question in cognitive and computational learning research. I say this all to hope to provide constructive feedback to the Veritasium team who's goal is seemingly to illuminate "truth" and not biased narratives. Though maybe I'm wrong, so please provide me feedback on this comment :)

Edit: I'd like to add a different example of different flavor: How to be a master/expert Computer Scientist as measured by making breakthroughs that reach the world at large. For example, with Neural Networks (NNs), a number of NN scientists had to go through decades of lack of support during "AI winters" before their boom and success now (which argues against repeated & timely attempts bc of decade long periods of time, environment validity bc the AI winters and lack of support were not indicative of later NN booms). What these scientist needed and had (on top of other factors) was persistence in the face of poor feedback from the public/research community, and dedication to work in a field where they would not get positive feedback for long periods of time.

To make this point more poignantly, imagine if Veritasium made their video in the middle of an "AI winter" and cited "see these NN computer scientists keep working in this field where they ignore all the feedback they get --which is predominantly negative, though for most part they don't get much feedback at all because lack of interest in NNs. These scientists are now dealing with low citations, low funding, low status, etc. This really stresses the importance of repeated timely feedback especially in the research world where finding are validated heavily in peer review."

I just saw the video on measuring the speed of light, and wanted to ask this.

I thought AM radio could be interesting here.

If I have a radio station broadcasting at 10 kHz, with c=300000 m/s I’d get a wavelength of 300 meters.

If I had a receiver to the east of the station I’ll be able to listen to the signal at the 10 kHz frequency.

If I had another receiver to the west of the station I’d be able to do the same.

If the speed of light would be different to any direction I’d have to use a different frequency depending on my position from the station. Unless you assume that the wavelength changes the same way. But the wavelength is something that you can measure without a clock, like the experiment with melting a bar of chocolate in the microwave.

Am I missing something?

In the latest around 10:30 Derek references a study with mice vs humans and how they react to a green vs red light which may shock them. Does anyone have a link to this study?

i had nothing to do so i recreated the prisoner experiment in javascript. i ran 10k simulations tho not one of them succeeded, i dont know if it was my program's error or what but here are the results:
- Method 1 (on the left side) is the method where prisoners randomly pick a box

- Method 2 (on the right) is the method with a 0.31% of success as said in the video

if anyone is interested in the source code:
you can just copy it and run it in your browser, this code is safe but note you should never copy a stranger's code and run it in your browser if you dont know what you're copying

I created a spreadsheet via Google Sheets that allows you to randomize the slip numbers and then see how that ordering effects the outcome of the prisoners (for those whom are interested):

I remember a video I watched from Derek where he asked Dustin a question, to which Dustin gave a reasonable answer followed by something like "I feel like there's a trick." Derek has a follow-up and Dustin's mind breaks. I cannot remember for the life of me which video this was. Any help?

According to Central Limit Theorem, the more games I simulate, the closer the winning_rate I get will be to the actual winning probability.

After waiting few minutes I got the result of 200.000 simulations of the strategy proposed and this is the result, pretty close, uh?

I'm gonna clean the code a bit (it's very simple) and share it

I’m most likely wrong but can someone tell me why can’t the universe be expanding because of the dark matter being too dense rather than dark energy. For example think of the universe as a ball and the pressure of the air in the ball is dense which causes the ball to expand, but in this case the air is dark matter. My guess on this idea being wrong is that the ball in the air is trying to regulate itself with the outside pressure. But there is absolutely nothing out of our universe which wouldn’t make our universe expand to it. But I’m not entirely sure. If anyone has any idea I would be pleased if you shared it with me.

Just 20 minutes ago or so, the video popped into my recommended videos tab on Youtube, and I ironically felt the urge to click on it. In the video, Derek makes the argument, that by making his videos 'almost misleading', he could engage bigger audiences, and thereby teach more. I agree that getting that it's a very valid reason, and that it may be the only way to engage more people and score more views, but I think the point of the videos might be missed.

A couple months ago, some friends of my family came to visit us, and their youngest son, who I think watches a lot of edutainment on Youtube commented on my salt lamp. He asked me if I knew it didn't work. For a split second I was very confused, because my salt lamp works as you'd expect it to work. It is rather good at illuminating. But after this moment where I didn't know what the fuck he was talking about, I came to recall the video on salt lamps Veritasium had made a couple years ago where he how negative ions don't do anything what so ever, and many of these 'healthy' products are a scam (I'm pretty sure that was the takeaway, its a while since i watched it). But that was not the main point that came across to this kid, because in the time between I and he had watched it, the title and thumbnail had been changed. It now reads something along the lines of "Do salt lamps work? No.", which is a very different message to: some products are actually not useful for what they are sold for. My salt lamp very much does work thank you, I just didn't buy it to cure cancer!

This little interaction I had was obviously completely harmless, but it goes to show how big a part of the perception on a video (or any other text for that matter) comes from its title and thumnail alone, instead of its contents, and how slight misrepresentations in those can accidentally give a wrong takeaway from something you made. Its a very easy way to create engagement to make someone feel like they'll know better than others if they watch your videos, but I feel like its an easy way to create a misunderstanding, leading to some kind of fight, because I definitly felt kind of attacked when I was told MY salt lamp didn't work.

I think the answer to this would need to involve a black hole.

1 box open both ends to allow light through, 1 sensor to detect the photon of light you want and...well you get the idea, I hope. The method may need some adjustments of course

What's your thoughts? Sorry for the title, I can't reddit well lol

Plus, apologies if this was proposed before. Tis 2:30am here and am slightly sleepy

So I’ve watched the video on how it’s impossible to measure one-way light and obviously got intrigued to find out ways to measure one-way light. I came up with a way, and while there is probably something wrong with my version, I’d be interested to see why.

So in my version I take one of the examples he had in the video:

• There are 2 clocks exactly 1km apart.

• There is a syncing device exactly 1/2km apart from each clock (directly in the middle).

• A laser is shot from one end of the clock to the other to measure the one-way speed of light.

My method differers from the one in the video with the syncing device. The syncing device in the video sends out a pulse that tries to sync the clocks but inevitably fails because one side of the syncing pulse could be slower than the other which in turn, offsets the clocks.

In my method, I try to avoid this issue by having the syncing device start two cars (or any object), one on each side, that travel exactly 1km/h. Because we know that a car traveling 1km/h takes the same amount of time in any direction, we can assume the clocks 1km apart are now synced with one another. Now we just shoot a laser from one end to the other and calculate the difference between the two clocks to get our answer.

If my method is wrong, clearly the issue lies within the two cars that are traveling exactly 1km/h to their respective clocks. But shouldn’t the two cars travel at the exact same speed no matter what direction the cars are traveling in resulting in synced clocks?

An explanation on why this wouldn’t work would be great.

Where he talks about Nikola Tesla's wireless energy tower. I can't seem to find it. Does anyone know what video this is? I remember him going to the spot that it was originally built and talking about why it didn't work out.

Here's my take on synchronizing clocks without introducing relative motion between them.

• To measure the light speed on opposite directions, have to light sources facing detectors on the other end in the same plane.

• Have a third light source large, coherent and parallel enough to encapsulate both the light sources that trigger at its pulse.

• The first two light sources are perpendicular the third light source and are the same distance from it so the clocks are synced at its pulse.

• All the light sources, clocks and detectors are stationary in the frame of reference that contains this entire experimental setup.

Attaching my to this set up.

Edit: Added image link

Hello all. I believe Derek said something similar or along the lines of my title above in one of his videos. Can you please share it with me, as I can't seem to find it.

I don't have an hour to re-watch all possible episodes that mention the term he coined, so I'm asking Reddit for help with this one... 😅

Given that Blackbird has already demonstrated that this is possible in air, is this possible in water?