A second video is at: kzread.info/dash/bejne/nqmWqdCkYLjApJM.html The new Objectivity video out today is also worth a look: kzread.info/dash/bejne/hZqtxo9ppLunosY.html

@Jcpo23

6 жыл бұрын

This video language is set to german so we can't have right automatic subtitles :/

@KevinTwiner

6 жыл бұрын

Awesomeness

@sachingiyer

6 жыл бұрын

Numberphile Is this how GPS triangulation works?

@petros_adamopoulos

6 жыл бұрын

The question is why would I NOT want to check out the other video.

@aeyet8184

6 жыл бұрын

@Numberphile - Could you please tell me of anything in reality that is 2 dimensional?

Foolish seismologist: "The earthquake originated from about 30km below the surface." Enlightened pure mathematician: "Or 30km above the surface."

@vunop3078

6 жыл бұрын

How is that "pure" mathematic when it doesnt account for the fact that not every output is right, that only heights below surface are the answere. It could as well be: Artist: Thats a Line. Mathematican: No thats a triangle with two angles of 0° and one 180° angle.

@anlumo1

6 жыл бұрын

Japan actually has had two earthquakes with an epicenter above the surface. However, the reason is not really funny.

@Sakkura1

6 жыл бұрын

The epicenter is always at the surface. It's the projection of the center onto the surface.

@kurtu5

6 жыл бұрын

Yeah the US used seismometers, and still does, to detect the hypocenter of atmospheric NUDETs. That job is where I learned my seismology.

@WiseSquash

6 жыл бұрын

projection of the hypocenter*

I'm a simple man. I see a Tadashi video, I click on it. Actually, I'm a complicated man. I have thoughts, feelings, and ideas.

@jamieg2427

6 жыл бұрын

Lol this meme.

@damienjones1487

6 жыл бұрын

Heavyboxes DIY Master why is your profile pic just your ir someone else's chin?

@HeavyboxesDIYMaster

6 жыл бұрын

alien the harold ... It's me. I just wanted to make it different.

@damienjones1487

5 жыл бұрын

Heavyboxes DIY Master its weel spooky i can not know i can handle it

@nipunajayatunge8924

4 жыл бұрын

None of us are just "one dimensional" like that! XD

Professor Tadashi should have his own channel, he explains things so well !

@numberphile

6 жыл бұрын

He has his own playlist here on Numberphile... bit.ly/tadashi_vids

@brian554xx

6 жыл бұрын

And that voice! He sounds like the universe explaining itself.

@Tympan

2 жыл бұрын

@@numberphile ok I’ve watched them all. So now make more!!

@pullt

2 жыл бұрын

He's well-spoken.

@fahrenheit2101

Жыл бұрын

Legitimately the best maths teacher I've ever witnessed.

MY BOI TADASHI IS BACK

@DrKaii

Жыл бұрын

He need to come back again

I would love to ask Professor Tadashi if he ever considered writing a book about mathematics and physics of our daily lives. I see that he clearly is one of the greatest science communicators of our time (maybe beyond that) and getting to know a little more on his personnal experiences and philosophy towards education, knowledge and such would be a treat. Of course, I hope the partnership with this channel will go on forever! P.S. Congratulations to the animation/edition guys. Superb job making an already didactic explanation even more understandable.

@QuasiELVIS

4 жыл бұрын

What would you want him to communicate? I think his genius is in how he speaks which you wouldn't get from a book.

@Kokurorokuko

3 жыл бұрын

@@QuasiELVIS what do you mean "how he speaks"? I'm sure it isn't the accent that delivers the point

@QuasiELVIS

3 жыл бұрын

@@Kokurorokuko he's just funny.

@Kokurorokuko

3 жыл бұрын

@@QuasiELVIS no only, he delivers information in a very approachable way

@want-diversecontent3887

3 жыл бұрын

@@Kokurorokuko Maybe the pacing?

It's funny that the p in p-wave stands for both "primary" and "pressure", while the s in s-wave stands for both "secondary" and "shear". The two polarization components of electromagnetic waves are termed p and s as well. In that case however, p means "parallel" (same in German), while s is German for "senkrecht" (since "perpendicular" also starts with p). Thanks for the great video, btw!

Good job to the animator on this video! Wow!

@expressrobkill

5 жыл бұрын

Kelvin Lee i know i could watch a show with this style of animation.

I dare say if your epicenter is above ground you shouldn't calculate but run for the nearest fallout shelter.

@christianbarnay2499

6 жыл бұрын

Also your distance measurement is all wrong because waves travelling through the air and through the earth have different shapes and speeds.

@Sakkura1

6 жыл бұрын

*Center. The epicenter is always at the surface, because it's the projection of the earthquake's center onto the surface.

@kurtu5

6 жыл бұрын

Hypocenter is the word you are looking for, and yes its also used for atmospheric nuclear detonations.

@kurtu5

4 жыл бұрын

@@uku4171 I think that for an atmospheric nuclear detonation, the epiccenter is the point on the earth's surface closest to the hypocenter(the center of the detonation). So in this case its above.

@petros_adamopoulos

4 жыл бұрын

"Usually we don't get earthquakes from above" he said very matter-of-factly.

I love his voice. It's very soothing. No morning classes from this guy.

Zilch is a rigorous mathematical term.

@MilesQuickster

6 жыл бұрын

Really now?

@kisaragiayami

6 жыл бұрын

Miles Quickster r/woooosh

@MilesQuickster

6 жыл бұрын

WTH...

@pablogriswold421

6 жыл бұрын

Miles Quickster I believe he meant to provide sound for the following situation: ------The Joke----> *WHOOOSH* -----Your head-----

@MilesQuickster

6 жыл бұрын

Oh. They think I'm serious 😒

Great as always, but I really enjoyed the low-tec visuals!

@hanniffydinn6019

6 жыл бұрын

stlCkofdOom they are called sweed

@IDoNotLikeHandlesOnYT

4 жыл бұрын

Really? I thought they were some of the least helpful visual aids I've ever seen, and I already had some knowledge of the stuff being discussed.

12:51 "What does it have to do with this theorem? Everything has to do with this theorem."

The epicenter is, by definition, always on the surface (of the earth). The point below the surface, where the earthquake happens, is called hypocenter.

@CrizTaylor

Жыл бұрын

no but, it is up above ground, in the air.

@algotkristoffersson15

6 ай бұрын

But if they are above and below the center respectively, where is the center?

I live in northern California, near the Hayward Fault. Before that, I lived closer to the San Andreas Fault. And in my experience living in earthquake zones, the P-wave is more up/down and the S-wave is more side/side. Tadashi's illustration makes sense, but I have a theory that the reason it's reversed in the illustration is because it fails to take depth into account. The closer to the epicenter you are, the more you feel the waves coming from below you, the more vertical the P-wave will be, and the more up/down motion it will cause.

Tadashi always amazes me.

@numberphile

6 жыл бұрын

Us too!

@jackren295

6 жыл бұрын

I actually observed this property of three intersecting circles and tried to proof it myself, and failed. Tadashi's explanation just blew my mind! I always loved space with different dimensions, and this video encapsulates my feeling.

Now if i had teachers like Tadashi i might actually have learned something in school lol

@rtt1961

6 жыл бұрын

Yes, this guy intermediately impressed me as very clear.

@flappy7373

6 жыл бұрын

was that a yoke m8?

@MsBombastik

6 жыл бұрын

no you would not, dont blame your/your parents incompetence on teachers

@meinbuch9458

6 жыл бұрын

Cypherous Blaming your teachers doesn't solve the problem,you ever heard of self-learning?

@shanematthews1985

6 жыл бұрын

Self learning the age before technology when you had no means of long distance transportation, back then all we really had were schools and the library, but without any kind of "reference" how would i have even been aware that something was seriously wrong, i mean we're not talking recent times here we're talking 2 decades :P

I love this video, I studied Surveying in college, and this theorem is right my alley. GPS positioning works on the same basis: you have multiple spheres, each emanating from the one of the GPS satellites, each meeting you GPS receiver's antenna. We can, generally speaking, determine the time it takes for each of them to reach you. With the first sphere, we can place you somewhere in space, on the surface of that sphere. When we add a second sphere, the two intersect to form a circle in space where you might be. Add a third sphere intersecting, and now we have you on either of two points. And just as we don't generally get earthquakes from above, only in exceptionally rare cases are we going to be way out in space. Instead, we can intuit that we are in fact at the one point of the intersection of three spheres... that intersects with a fourth spheroid, namely the earth! Now, since there are lots of variables involved with the measuring the time is takes for each of those radio signals (spheres) to reach you, we can use the redundant data from the spheres of additional GPS satellites to refine our calculated position. So too, 4 or 5 or more seismometers are used to pin point the epicenter of an earthquake!

small error in terminology: epicenter refers to the point on the earth's surface directly above the source of the earthquake, itself called the hypocenter. so if a line is constructed between the 2 meeting points of the spheres, the bottom point will be the hypocenter and the point at which the line intersects the surface of the earth will be the epicenter. edit: more trivia: for mid-air explosions, it's the opposite; hypocenter on surface, epicenter is explosion source. the math works out the same except sometimes instead of counting the seconds between the flash and the rumble, you start counting when you go blind and stop counting when your organs rupture. or you don't have time to count.

@Sakkura1

6 жыл бұрын

You can also just call it the center or focus, hypocenter is an unnecessary backformation.

@kurtu5

6 жыл бұрын

hypocenter is nicer because any nuclear scientist or geologists will know immediately what you mean. If you say focus or center, it could be anything.

@deejuggle

6 жыл бұрын

r77xxl thanks! This is exactly the sort of semantic trivia that I love. Will definitely use.

@ELFanatic

4 жыл бұрын

I'm pretty sure that's what he's explaining at the very end

@JackFlashTech

4 жыл бұрын

The hypocenter is at the intersection of the spheres, but the epicenter is at the intersection of the chords of the circles, so I’m not sure he’s as off as all that.

'Usually we don't have earth quakes from above', this made my day :) this guy is my new favorite on Numberphile

@topilinkala1594

Жыл бұрын

There is a ban on athmospheric atomic bomb tests, so if we assume everyone holds the ban the "quake" must have been underground. Seismographs are easy way to detect atomic (or hydrogenic) bomb tests.

I would love to have a lecturer who teaches like professor Tadashi. He is excellent at explaining things

Earthquake so strong that it makes Japanese women scream like Wilhelm..

The explanations of Tadashi are always so amazing. Great video!

As a geologist this is a wonderful explanation. Love it!

Lovely animation, it's great to see this channel improving.

Wow. This is one of my favorite Numberphile videos. I am getting the tingles, because the connections he is able to make and explain so clearly are elegant and insightful

This was the very first time watching one of your videos. I've been subscribed to it for a little while, but never got around to it. Absolutely fascinating.

Tadashi-sensei is a great explainer. I could never interpret the difference between pressure waves and shear waves.

I'm a 42 year old man and I just love the playfulness of Tadashi's videos. There can never be too many Tadashi videos so make more :-)

Man, the animation here is so brilliant. I'm always impressed by the animation for the Tadashi videos. Keep up the great work!!

Love the editing and visuals 😍😍 Thank you xoxo

This was so beautifully executed. His teaching method is so clear, so *graspable*, that I sincerely just want to sit at his feet for a few years and take it all in.

I love how professor Tadashi explain things and the animations were awesome

Absolutely brilliant, I love prof. Tadahi's videos and great work with the animations.

Pretty sure I heard a Wilhelm scream.

I really enjoyed this video and the creative visualisations too.

Tadashi is so gifted, they can teach me things I don't understand and, (as is the case today), keep me entertained and interested even when explaining something I already understand.

I know it's been over a year since this was made but this professor is so much fun. He's very clear and easy to understand.

I couldn't stop laughing at the spasmodic ring of fire

I love the recent increase in Numberphile's animation production value! 💕👌

The animations are amazing. Just add perfectly to the great content.

one of the best numberphile videos of all time

Tadashi is straight-up my favorite Numberphile guest. He always brings something interesting to the table. I wish he was one of the "regulars".

I love his illustrations and animations. I think I say that on every video you put out with him in it.

understood this *completely* this man is a wonderful, wonderful teacher. Tadashi.

This one has great animations. Well done!

Great video and easy to follow. The animations are superb. The tectonic plate spazzing around had me laughing out loud.

Ah! The animations!

Visuals of this make me feel like I am back in Beakman's world, basically, I loved them!

That idea of measuring the seconds between two waves or between the lightning and the thunder actually has an interesting application in military combat scenarios. Due to the fact that most sniper rifle bullets move at well in excess of the speed of sound, you actually use the elapsed time between the supersonic crack of a bullet going past you and the thump of the rifle that fired it going off in the distance, and you can actually estimate the distance that the enemy sniper fired at you from. If you take that most rounds that might be fired at you from long range have a muzzle velocity of between 700 and 800 m/s (we'll call it at the average of 750 m/s), and the speed of sound is about 343 m/s, and then you account for all the things that slow a bullet down after it leaves the muzzle, like air resistance, wind, gravity, etc., then you get a delay of somewhere just over 300 meters for every second between the crack of the bullet whizzing past you and the thump of the rifle going off. When you hear a crack, start counting (as you take cover, of course). 2 second elapsed means the enemy sniper is approximately just beyond 600 meters from your position. Snipers call the technique "Crack-Thump", and it's extremely useful in helping to find the enemy sniper who's shooting at you so you can engage him and win the fight. Most of you will never need that information, but for what it's worth there's actually a lot of really cool applications for math, mainly for geometry and trigonometry, in long range shooting.

His drawing with him and his baby is absolutely adorable.

Brady, you have just the coolest job ever.

Fantastic! Thank you Professor Tadashi!

this is fantastic.. a maths teacher with passion and ability to explain complexity with ease.. considering the copiousness amount dross on KZread this is quality.. thanks for posting. am looking forward to more :-)

The animations are sick..🔥🔥🔥

Super interesting! I am not sure how exactly I got to this channel but definitely I am subscribing now!

Love the new visualization style!

Love the graphics in this one.

Just experienced an earthquake and used his method to check how far the earthquake was, and what do u know, it was spot on 😂

Every single school and university should have someone like professor Tadashi

15:30 "-Of course, the epicenter could have been above as well. -Usually, we don't get an earthquake from above" 😂

Really lovely animation, and a very nice explanation for a Californian who should have known this by now.

Thanks for an excellent presentation.

this guy is a gift.. Thank you

Both the math and the earthquake calculation were stunning!!

The animator behind these videos is also brilliant. Your hard work is much appreciated!

Currently living in Japan, this was quite interesting!😊

Fantastic video! Thank you.

Beautiful. And very well explained.

Great video and especially great production

Great subject matter, great video. Thanks

he draws with words. Its so clear

I love the beginning!

I have learned SO much about earthquakes, thank you!

This was beautiful.

Tadashi is always great

Loving the editing in this one.

ah wow, this is another brilliant one, and despite the simple exposition equisitely intellectually stimulating. well done!

I love this professor and his awesome stories. 😎👍

Thank you for sharing this great video!

aww, we have baby Tadashi now will this channel still be around when he/she is able to grasp these ideas..

Excellent demonstration Professor!

love the animations!

I love Tadashi's explanations

I first learned about this kind of spherical triangulation while playing Eve online. Was really helpful in visualizing the scanning probes functionality.

Dr Tokieda is such an amazing explainer. I was going to say, "like a Richard Feynman of mathematics," but then Tadashi is sort of a physicist too. Maybe that's what gave them such intuitive descriptions for math!

Nice. That gives both the epicenter and focus of a quake.

That was so beautiful and informative!

The animations in this one were fantastic

Beautiful animations and stop motion!

He never disappoints - yet another very interesting mathematical theorem and its application

Tadashi is my favorite!

Beautiful video! Thx

Great video, I accept to wait for the next video that shows that we can reject the point from above using 4-dimensional spheres.

@ideallyyours

4 жыл бұрын

As described in the video, 3 spheres intersecting forms a singular line of contact. To determine a singular *point*, you just need to use the intersection of a 4th sphere across that line. No 4th dimension is necessary.

That was extremely fascinating great video!

absolutely fascinating

Beautiful video!

What a great explanation!

I love this guy so much!

Excellent educational value. Teach theorem plus practical application in a few minutes .