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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: https://www.youtube.com/watch?v=QTvtNbGBiCg

###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"

#####Here is a rough diagram of the "solution" that I am suggesting. (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.

SCENARIO 1: 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

SCENARIO 2: 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

SCENARIO 3: 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:

Diagram

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 The 4 things it takes to be an expert 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!

​

https://preview.redd.it/ukxk06kssnxa1.png?width=478&format=png&auto=webp&s=65f465d36cf528c4e5e0ca1f546446889de42387

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:"

https://www.youtube.com/watch?v=cqRndpt65RQ&t=382s

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 this video right here, 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 (https://www.youtube.com/watch?v=cmLM8H2iVEA)

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

https://preview.redd.it/f338mkun3bba1.png?width=533&format=png&auto=webp&s=4405dcf42795d157c128af004d4477aaef94357e

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?

https://youtu.be/nmgFG7PUHfo?t=239 This also appeared in the video: "Maths Fundamental Flaw" at 29:48 https://youtu.be/HeQX2HjkcNo?t=1789

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.

https://www.youtube.com/watch?v=ljoeOLuX6Z4

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 https://en.wikipedia.org/wiki/Fertilizer#Energy_consumption_and_sustainability

Seems that at the current rate we'll run out of natural gas in 52 years https://www.worldometers.info/gas/

Looks like a very tangible correlation is already established https://www.theatlantic.com/technology/archive/2016/12/will-humans-run-out-of-fertilizer/510557/
https://www.spglobal.com/commodityinsights/en/market-insights/blogs/agriculture/011922-fertilizer-costs-natural-gas-prices

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:

1. Part 1 - Food entering and disappearing
2. Part 2 - Refining models
3. Part 3 - Headstands and vomit