I remember cosmo came out, around the same time of taking high-school physics, and I was learning more once a week on Fox than that whole week in school.
I saw that Delta plane landing in LAX! I was a Delta F/A for 20 years and landed there many times. There is a parking garage in San Diego that is right under the planes landing. The sound as you stand on the top level is incredible - totally fills you up.
That imagery at 11:25 of the F/A-18 fighter was of a Vapor Cone, not from breaking the sound barrier. Vapor Cones are a condition of moist air and temperature at transonic speeds. I make this point because it’s often misconstrued that the two events are the same.
@@TheRealSkeletor you’re wrong, I’m a photographer and every airshow I’ve been to with moisture in the air has shown this phenomenon. The fighter jets are not allowed to travel at supersonic speeds during airshows without the permission of the FAA. You don’t have to take my word for it, Google is your friend.
@@NaughtyShepherd the speed needed for the cone is still close enough to speed on sound. And in the clip, you dont know are you cant know it its breaking the speed of sound or not, it has a vapor cone yeah, but that doesnt mean its not breaking the barrier. Just that having the cone is not necessarily a sign for it
I totally agree with your assessment. I live right at the south end of DFW airport for a while on Valley View Lane. Being fascinated with aircraft anyway I would sit out there and watch them as they came over and if the humidity was high and especially if it was foggy... almost spooky looking the way the fog swirled around the top and back of the plane. I'm not a genius and I don't have much education but I think it has a lot to do with the vacuum the Lord air pressure causes the moisture to become so thick that it becomes more visible because there is just more water there. Someone who knows correct me if I'm wrong but I believe it's totally because of a lord air pressure in certain areas more water vapor out of the air
Y'know. Another great example of this is if a motorcycle is coming towards you playing a song on the radio. You'll notice the song, especially if you know it, sounds awful and weird, up until it gets Infront of you and then it gets worse as it goes away and the pitch drops! Wow. Neat to think about it like this now.
Just had a thought of another great D.E. of when a vicious dog’s barkin’ hysterically as it approaches &, races PAST our foothold location, after something else entirely
I get goosebumps when a car playing music passes on a somewhat empty road (especially at night). As it approaches the listener, it sounds quite high pitched and then as it leaves it sounds deeper and quite eerie. This always gave me goose bumps! The explanation known as the doppler effect really settled my nerves and boosted my fascination with physics!
Its the lower portions of the tires that are moving "in reverse"..... though technically, i think itd be a net zero in movement as it would be the point of contact
I just realized that Chuck is actually the secret sauce of Startalk. As great Neil is at communicating complex ideas, Chuck's humor adds an extra layer of translation to further help us mere mortals understand, and be open to, what is being said. 👍 So here's my question: I'm driving my rocket-powered Corvette at Bonneville, and I SMASH through the sound barrier. From my perspective, can I still hear my engines? Can I hear anything at all, be it from inside the car or from the outside?
You would only hear any sound coming from in front of you at that point, nothing from behind you, as you are outrunning any sound waves coming from behind. So if it's a rear engine, you wouldn't be able to hear your own engine once you pass the sound barrier.
@@TheRealSkeletor I had the same question, thanks. Further on that, did I understand it correctly that you'll hear a "cacophony" (similar to what you'd hear if you standing by the highway) if the car drives past you?
Most of what's said here only applies to the outside air which is flowing past the vehicle faster than sound. The body of the vehicle and the air inside, as well as air in wheel wells and other holes depending on the shape, will be moving more slowly, or not at all, relative to you, the listener. All of these things will transmit sound as expected by Doppler, and you'll definitely hear your engine, no matter what part of the vehicle it or you are inside of. If the top's down, you probably won't hear anything but a sharp ringing, because your eardrums have burst.
One of the eeriest experiences I had with sound was at the top of an airport garage on the final approach to San Diego airport, where are the planes or just a couple of hundred feet above you. After jets passed close by there would be this roaring noise, and I realized it was the wing tips vortexes (which in jets’ landing figuration are very strong). One of them roared very loudly, and ended with a very loud snap as it broke up that really startled me. It took me a while to figure out what had caused it.
I think at the end of the video, Neil was talking about the wheels, which are simply rotating but not going forward (or backward). The train type Is the old steam locomotive, which has a 'rod', which turns the main wheel, and it goes once forfards, faster than the train, but after that backwards, and in the next cycle forwards and backwards again. Hovewer, you can't cheat the police with either of those because it is all relative to the moving object. The whole object as a system is still going to move towards the police radar, and it will always be able to measure the speed until you manage to disable the reflection of the radar signs, or you send stronger fake radio waves at similar frequency.
The rod does not go backwards but at one point it will be stationary wrt he ground. As is seemingly "goes backwards" it is actually approaching the point where it is stationary.
@@madman2096 Yes, my description is relative to the moving object, I mentioned that later. At the moment the wheel touches the ground the rod stops relative to the ground, to start speeding up in the next moment.
What Neil hinted at is not relative to the type of vehicle. The point of the wheels touching the ground or rail is not moving, relative to the ground or rail. (By the same principle, the top of the wheel is moving at exactly double the vehicle speed.) The rims of the train wheel (even those ones they add to service pickup trucks) are moving slightly backward below the active rail surface.
Neil, could you possibly do an explainer on "wave drag" and explain why commercial airplanes have effectively had a speed limit of just below the speed of sound implemented on them despite engines becoming more efficient and powerful? Sorry about the run-on sentence.
That's why you turn slightly depending on the geometry of the streets. Not only do you lengthen the distance and appear to go slower they measure your sideways speed not your forward speed
I want a whole compilation video of Neil doing the sound with as many ridiculous things in it as possible....so funny. Every time Neil made the sound, Chuck laughed...Gary just kinda smirked. I find it so funny.
The crankshaft inside the engine is spinning, therefore one side is going faster than the car, but the opposite side is going slower. Something similar happens with the tires. The part that is in contact with the road goes at 0MPH and the top at 2x the speed of the car.
As for the car parts that are stationary, and the train parts that are moving backwards-even though the respective vehicles are moving forward: Neil is, of course, talking about wheels. Specifically, the portion of the wheel that's momentarily in contact with the road or rail is momentarily stationary. And the portion of the train's wheels that are below the region of contact-the flanges-are momentarily moving backward. Assuming, of course, that the vehicle is not skidding! 🤣 But that got me thinking: Surely there are other parts that are moving backward as well? Depending on how they're mounted, it could be portions of: piston / crank / cam shaft, flywheel, fan blade, fan belt, and any number of valves, actuators, gears, rotors, and internal wheels. I've excluded sound waves, air, wiper fluid etc. since they are not car parts.
There is also a portion of those same wheels that is travelling at twice the speed of the vehicle, relative to ground. This, of course, would be TDC (top dead center for you non-machinists) of the wheel.
@@kilroy1964 barely due to weight compression of the contact patch of the wheel, right? This is like arguing that fuel at 3.999$/ gal isn't 4$ a gallon
its sad that you dont understand that the speakers are not there to reproduce the car sounds.... there are no mics from car sounds going to the on track speakers... I can say this with confidence because I have worked for NASCAR directly, specifically doing things involving sound the cars are so loud, that you will hear all the dopplars from all of the cars all at once.. this masks the actual dopplar sound so it will sound like one giant roar...they become indistinct the gaint roar is even louder if you are in the infield as it gets compounded by being reflected off the walls
Doppler shift refers to the change in frequency or wavelength of a wave as observed by someone moving relative to the wave source, commonly experienced with sound and light waves. In the context of sonic bombs, the Doppler effect can create intense and disorienting sounds by compressing or stretching sound waves, potentially amplifying their impact. This phenomenon highlights how Doppler shift can influence not just scientific measurements but also practical applications with significant effects. How might our understanding of Doppler shift and its applications in sound technology evolve with advancements in acoustic research?
17:36 The contact patch between the tire and the asphalt is not going forward. In relation to the ground it is stationary. In relation to the car it is going backwards, at the same speed at which the car is going forwards in relationship to the ground. The TOP of the tire, at any forward speed, is going forward slightly more than twice the speed in relation to the ground as the car is moving in relation to the ground. the top of the tire is going slightly faster in relation to the CAR than the car is going in relation to the ground.
Mythbusters did an episode on trying to defeat a radar gun. They didn't find any material you could coat your car with that did the job. Plus, the cops they interviewed pointed out that if they see a car covered in some kind of strange stuff or having unusual things affixed to the roof or something, that is only going to attract their attention more.
wheels. contact point is 0, opposite side is *2 forward vehicle velocity. the tires would break sound barrier at only half the speed of sound of the rest of the vehicle.
Buys Ballot was also 'the guy' who worked out that, if, in the northern hemisphere, you stand with your back to the wind - low atmospheric pressure is always on your left. Prior to weather radar and weather forecasts this was most important to sailors & aviators.
We tune 10-20 khz to receive low earth orbiting amateur radio satellites and the ISS, and tune down as it approaches and continue tuning below their transmit frequency until Loss of signal because of that earth curvature.
They don't do that at every track. Atlanta motor speedway is one of the fastest tracks, and now, they have the same rules as Daytona so they're going the same speeds, it's a wonderful sound to really experience. And than, you can hear the cars engine noise bouncing through the infield off of other things, buildings, haulers, hearing THAT specific sound is so weird, you can't pinpoint where the sound is coming from until you've experienced it for a few times.
Question if you were in water and you make a wave and then make a stronger wave behind it that is strong enough to catch it it makes the original wave stronger and faster do sound waves work the same
Which is wrong because sirens _don't_ demonstrate the Doppler effect. Siren on emergency vehicles-ambulances, police cars, fire trucks etc.-do _not_ emit sound at a constant frequency. They are specifically designed to continuously vary their pitch, tone, and overall sound pattern in order to grab everybody's attention. So, regardless of whether it's stationary or moving relative to you, you're going to hear the siren's pitch change constantly. It's _not_ due to the Doppler effect. And yet, so many people mistakenly use ambulance sirens as an example of Doppler shift. Sad 😢.
@@nHans yes the pitch changes as well, because averything is subject to doppler effects. I live in a enormous city where one airport is far away from where most people live, and another is one where the aproach is made over sea. Couldnt use that as an example ruclips.net/video/imoxDcn2Sgo/видео.html
@@nHans you are confused nHans and spreading misinformation. Moving sirens are affected by Doppler Shift. I understand what you mean; siren pitches vary purposely but those patterned sequences are affected as a whole as the siren approaching is higher in general pitch and lower as it leaves or moves away from the listener. Please apologize for misunderstanding and misinforming anyone else you have made this reply to.
@nHans was confused and misinformed you in his reply. You learning about Doppler Shift with an ambulance siren as an example is fine as long as you understand the shift of its pitch as it approaches then passes and goes away is the affected sound of the siren due to Doppler Shift. Good day!
@@stevemccoy6434 Nevermind that. I wish there were more kind people like you in the internet nowadays - the problem is is my city that was the only sound loud enough and common enough to be used as an example. Apollogies very well accepted!
That InO on the south runway of LAX was the closest one to my work. They redid the parking lot so the drivethrough could have 20 cars without clogging the road in front of the small park across from it. I got tired after working there for 10 years with the planes landing that I got annoyed with someone holding up the line of cars that I honked at them when they didn't move. I'd gotten used to Airbus 380's and Boeing 747's landing that I didn't care anymore.
I have a suggestion/question(s). An episode based on the view from Mars while on Mars and other benefits of living/working on the red planet. Could Mars also be used to build and launch light sails or give us more access to our outer planets with a large land based telescope? Less gravity and open space for lasers would give it some advantages. I'm also curious about why we didn't explore the idea of landing a fixed object onto Oumuamua. If we can land objects on a comet what's the difference of adding say a video feed and tracker onto a interstellar object with a lander module?
Well in order to land on anything without just smashing into it. We would need to match its speed and direction pretty close. We have nothing currently that could have matched Oumuamua speed and direction.
Go over drifting next!!! The science in the steering geometry and unique corner G's is enuf alone! Let alone how the suspension is made to continue to accelerate when sideways!
Neil can you please do an episode on the missing Malaysian B777.And how Immarsat used the Doppler shift of the pings of the Engine motoring system to determine its final flight path? .Thank you.
No. Sound only travels through matter and sound ends when molecules or atoms cannot touch each other directly. No sound is transmitted in the upper limits of the atmosphere, or in space. Residual heat may be radiated by sound interaction, but that effect is not directional enough to propel a vehicle, nor efficient for the amount of work done to produce sound.
I have been to that In-N-Out burger next to LAX many times, enjoying the burgers and hanging out at the little park across the street enjoying the great views of the airplanes landing at LAX, it's especially awesome when you get to see a 747 or an A380👍🙂 Definitely enjoying those Doppler sounds from those big airplanes arriving and the turbulent air sounds trailing behind them✈👍🙂
Indy 500 1976. I was 8 years old riveted by the Doppler shift at high volume of the race cars screaming past with that 💥 the moment they passed in front of my ears, with the vibration passing through my whole body. Speakers at Daytona sounds very disappointing.
NEIL PLEASE ANSWER ME: JWST has detected galaxies far more developed than predicted in the begining of the universe. Can it be that TIME ITSELF has beeng stretching too and thats why we see those galaxies as so developed? Maybe time itself on that early universe run at a different speed from ours? A Time´s Dopller Effect? I CAN NOT SLEEP THINKING ON THIS
9:25 Ok, Neil, Consider This!! Two orchestras on the same train but on two separate flat open cars: Orchestra #1 is closer to the direction of travel or 'front' and orchestra #2 is trailing. If Orchestra #1 plays a note .. and Orchestra #2 is told to listen to Orchestra #1 and play the same note .. Orchestra #2 will end up playing a higher note, because even though they are not traveling any closer to orchestra #1, at any instant while they listen, they are traveling toward the LOCATION where the note was produced!! If Orchestra #2 plays a note, and #1 is told to listen and play the same note, #1 will end up playing a lower note, because at any instant while they listen, they are traveling farther away from the location where the note was produced.
Nobody has commented for a year, but I’m hoping someone can answer this question. I get that the sonic boom occurs right at the speed of sound due to all of the soundwaves being stacked on top of one another. But why is there still a sonic boom when traveling faster than the speed of sound?
So the thing that occurs when we break the sound barrier that we can see with moisture in the air blasting like a wall being traversed, what will occur when we succeed in breaking the light barrier? Light will be blue shifted in front, red shifted behind, like it is with galaxies and then... what? Do we have mathematics that describes this effect or have we used photon waves subbed in to sound wave equations?
This is when the calculator displays "Error." We have no specific equations for proving this because nothing breaks the speed of light. You can only change the medium to something in which light travels faster, or find a wormhole-style shortcut that eliminates the distance between two points. The blue and red shift you describe is observed in very fast travel but less than the speed of light. Red and blue shift are the Doppler effect's pitch change translated into to radiation frequencies. They're how we know the universe is expanding. The imaginary situation where we could break that speed, however, goes far beyond red and blue shift. All light is seen in front of you - total white-out and no objects can be distinguished. (You're also bombarded by unseen radiations.) Behind you is only black, as no light can catch up to you. This is simplified, but the basic idea as I've heard it presented by some of Neil's fellow physicists.
If you were strapped to the front of a plane flying under the speed of sound but accelerating, when breaking the speed of sound would you suddenly stop hearing the plane? That has always made sense to me but never quite been sure
You would definitely not hear the plane through the air, for two reasons. First, the sound waves are all behind you and can't move faster than their own speed limit. Second, your eardrums would have burst, likely before the sonic boom crashed trough your body. The latter may cause internal damage if you're at the focal point of a supersonic plane, but understandably no person has been put in this situation. (Sky dives that go supersonic don't have as much "boom" as a plane.) That said, if the air pressure is removed from the equation as far as your hearing is concerned, you would still hear the rumble of the plane vibrating from the metal then through your body; more so if your head is in direct contact with the plane. The skull is a great sound conductor.
Sound's a vibration in a medium. If you shout, your vocal chords make the air jiggle, which makes the air around it jiggle, all the way to someone's ear which has a membrane that jiggles and gets decoded by your brain as a sound. Sound isn't a thing in and of itself; there's no sound waves in space because there's nothing there to vibrate. If you string up two cans together, the vibration gets carried through the string. People in space can talk to each other by putting their helmets together so the glass vibrates. So the 'speed of sound' is the speed at which the vibration gets pushed along in air. The _matter_ can be moving but the _sound_ is a thing generated by motion at a certain threshold, so your question doesn't make sense. Which is fine; now you know.
That only applies to specific speed infractions and won't work with every judge. If they can't prove speed, they can usually still charge you with driving faster than safe for conditions, especially if they saw you hit the brakes when you noticed the cop. (Before the lights were flashing.) This infers _you_ thought you were guilty of driving too fast.
Come do a follow up remote in Austin at Circuit of America's then Boca Chica! Formula too! plus good musical guests. Big DeGrass-Tyson fans as still allowed to share teachings in classrooms🚀
I've been to a lot of NASCAR races in my life, and I have no idea what Neil meant by not hearing the Doppler Effect. If he was in a suite, up high, far from the track, enclosed in glass, with speakers I maybe can see where he's coming from. But if you're outside/up close, the actual exhaust sounds overpower any speaker systems when the cars pass by. Typically at Daytona the cars run grouped together in a draft and if they are far away from you (the daytona backstretch is probably a mile away from the main grandstands) I imagine there shouldn't be much of a noticeable pitch change. Also, the speaker systems aren't used to (intentionally) emit engine sounds, it might just be excess noise getting into the track announcer's mic!
Another great example of what sound a plane makes just by gliding through the air is the Space Shuttle, most landing footage from Kennedy Space Center had great audio of the Shuttle, in the past i would think where is the jet fighter flying overhead but no it was just the Shuttle sound :)
If a cop is running towards your car with his radar - it'll show sum of your and his speed: the faster he's running - the more you're in trouble (: Also zero-speed point of moving car is the point of contact of wheel and road (unless sliding or drag-racing, obviously). Train "backwards moving part" is part of wheel's rim that is currently lower than top of the rail.
CHUCK!!! My F1 fellow fan!!! That was so exhilarating just to hear you'd rather follow F1. I was tickled to learn this. Who's your driver/team??? You think Alonzo will win this year?? Will Lewis persevere in achieving his 8th??? Peace to you and yours.
There is flex in the components of most machines. Unless you invent a device that starts and stops every atom in the in the assembly within the same time reference, all of those individual atoms will be crashing into one another, and pulling apart from one another, on the scales that we design them to handle. However, I am very curious about this stuff, and happy to be wrong and learn whatever i can.
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I wished I had Neil as my teacher in my early school days The way he makes seemingly difficult science topics simple and comprehensive
Yes, and fun.
I wish I had chuck as a teacher. xD
Yep but that’s because he doesn’t have to teach you how to calculate everything he explains 😂
@@janusatthegate6201 I was going to say that ,darn it.🤔
I remember cosmo came out, around the same time of taking high-school physics, and I was learning more once a week on Fox than that whole week in school.
Gary is always a nice addition to Neil and Chuck. StarTalk posts combine fun with knowledge. A potent and appreciated combination. Thanks, guys!
Found it fascinating, and specially that it goes till the speed of sound.
Thanks Dr.Tyson
I listen all day to you guys all day. Love Star Talk!
I saw that Delta plane landing in LAX! I was a Delta F/A for 20 years and landed there many times. There is a parking garage in San Diego that is right under the planes landing. The sound as you stand on the top level is incredible - totally fills you up.
That imagery at 11:25 of the F/A-18 fighter was of a Vapor Cone, not from breaking the sound barrier. Vapor Cones are a condition of moist air and temperature at transonic speeds.
I make this point because it’s often misconstrued that the two events are the same.
You don't get a visible vapor cone from anything traveling at subsonic speeds, so they are related phenomena.
@@TheRealSkeletor you’re wrong, I’m a photographer and every airshow I’ve been to with moisture in the air has shown this phenomenon. The fighter jets are not allowed to travel at supersonic speeds during airshows without the permission of the FAA.
You don’t have to take my word for it, Google is your friend.
@@TheRealSkeletor you get vapor cone from subsonic speeds, but still, speeds close to mach 1
@@NaughtyShepherd the speed needed for the cone is still close enough to speed on sound. And in the clip, you dont know are you cant know it its breaking the speed of sound or not, it has a vapor cone yeah, but that doesnt mean its not breaking the barrier. Just that having the cone is not necessarily a sign for it
I totally agree with your assessment.
I live right at the south end of DFW airport for a while on Valley View Lane.
Being fascinated with aircraft anyway I would sit out there and watch them as they came over and if the humidity was high and especially if it was foggy... almost spooky looking the way the fog swirled around the top and back of the plane.
I'm not a genius and I don't have much education but I think it has a lot to do with the vacuum the Lord air pressure causes the moisture to become so thick that it becomes more visible because there is just more water there.
Someone who knows correct me if I'm wrong but I believe it's totally because of a lord air pressure in certain areas more water vapor out of the air
Y'know. Another great example of this is if a motorcycle is coming towards you playing a song on the radio. You'll notice the song, especially if you know it, sounds awful and weird, up until it gets Infront of you and then it gets worse as it goes away and the pitch drops! Wow. Neat to think about it like this now.
My two favorite examples of the Doppler shift are: A train blowing it's horn as it passes by, and Indy cars as they pass as well.
Just had a thought of another great D.E. of when a vicious dog’s barkin’ hysterically as it approaches &, races PAST our foothold location, after something else entirely
A favorite of mine is high speed jet passes. (At air shows and NOT war zones.)
The engines are still around 40-60% powered at that In-N-Out. Airliners don't go fully idle until just 20-30 feet above the runway.
Neil making these sounds have made my day!
Gary is hilarious. Chuck is too, but he always is. Gary had his coffee this morning.
Amazing explanation about the Doppler Shift and I love how neil used cars and aircrafts to make examples of how sound works relative to the observer.
I get goosebumps when a car playing music passes on a somewhat empty road (especially at night). As it approaches the listener, it sounds quite high pitched and then as it leaves it sounds deeper and quite eerie. This always gave me goose bumps! The explanation known as the doppler effect really settled my nerves and boosted my fascination with physics!
In the stands at NHRA drag racing is the purest sound and you can actually feel it move left to right across your chest, or right to left
Lord Nice's humor is half the reason I love these videos so much.
so when you move twice the speed of sound, the sound just goes backward at a normal speed & volume?
Chuck's wit exceeds the speed of sound. That guy is right on cue every time.
Is there any study of Dopler effect at supersonic speeds?
Sounds nice to see what happens
Its the lower portions of the tires that are moving "in reverse"..... though technically, i think itd be a net zero in movement as it would be the point of contact
Thanks Neil!!! I enjoy your content so so much!!❤
When cars are all electric will they stop racing, or will it still be needed to test things?
The tires go backward.
I love watching videos on physics topics from people who are passionate about it. Cant get enough
Neil and Chuck is epic.
I just realized that Chuck is actually the secret sauce of Startalk. As great Neil is at communicating complex ideas, Chuck's humor adds an extra layer of translation to further help us mere mortals understand, and be open to, what is being said. 👍
So here's my question: I'm driving my rocket-powered Corvette at Bonneville, and I SMASH through the sound barrier. From my perspective, can I still hear my engines? Can I hear anything at all, be it from inside the car or from the outside?
You would only hear any sound coming from in front of you at that point, nothing from behind you, as you are outrunning any sound waves coming from behind. So if it's a rear engine, you wouldn't be able to hear your own engine once you pass the sound barrier.
@@TheRealSkeletor I had the same question, thanks. Further on that, did I understand it correctly that you'll hear a "cacophony" (similar to what you'd hear if you standing by the highway) if the car drives past you?
@@controversial1994 Yeah, that's a pretty good description for it.
@@TheRealSkeletor Thanks, much appreciated.
Most of what's said here only applies to the outside air which is flowing past the vehicle faster than sound. The body of the vehicle and the air inside, as well as air in wheel wells and other holes depending on the shape, will be moving more slowly, or not at all, relative to you, the listener. All of these things will transmit sound as expected by Doppler, and you'll definitely hear your engine, no matter what part of the vehicle it or you are inside of.
If the top's down, you probably won't hear anything but a sharp ringing, because your eardrums have burst.
The part of the tire that is inconstant contact with the ground is not moving forward
If you want the Doppler effect at a car race, go to a Formula 1 race, you'll be in Doppler heaven
Especially before the current hybrid era. I had goosebumps when I was about couple of kms away from the track complex.
One of the eeriest experiences I had with sound was at the top of an airport garage on the final approach to San Diego airport, where are the planes or just a couple of hundred feet above you. After jets passed close by there would be this roaring noise, and I realized it was the wing tips vortexes (which in jets’ landing figuration are very strong). One of them roared very loudly, and ended with a very loud snap as it broke up that really startled me. It took me a while to figure out what had caused it.
Thank you sir for bringing such informative videos to us through these exciting videos ✨... Neeeaaoonn!!
I think at the end of the video, Neil was talking about the wheels, which are simply rotating but not going forward (or backward).
The train type Is the old steam locomotive, which has a 'rod', which turns the main wheel, and it goes once forfards, faster than the train, but after that backwards, and in the next cycle forwards and backwards again.
Hovewer, you can't cheat the police with either of those because it is all relative to the moving object. The whole object as a system is still going to move towards the police radar, and it will always be able to measure the speed until you manage to disable the reflection of the radar signs, or you send stronger fake radio waves at similar frequency.
The rod does not go backwards but at one point it will be stationary wrt he ground. As is seemingly "goes backwards" it is actually approaching the point where it is stationary.
@@madman2096 Yes, my description is relative to the moving object, I mentioned that later. At the moment the wheel touches the ground the rod stops relative to the ground, to start speeding up in the next moment.
What Neil hinted at is not relative to the type of vehicle. The point of the wheels touching the ground or rail is not moving, relative to the ground or rail. (By the same principle, the top of the wheel is moving at exactly double the vehicle speed.) The rims of the train wheel (even those ones they add to service pickup trucks) are moving slightly backward below the active rail surface.
Neil, could you possibly do an explainer on "wave drag" and explain why commercial airplanes have effectively had a speed limit of just below the speed of sound implemented on them despite engines becoming more efficient and powerful?
Sorry about the run-on sentence.
Yes please
Boom boom on the no run on, great Q.
Doc, I would like to hear a discussion of John Boyd’s Energy Maneuverability Theory.
This is an amazing episode. It makes me think about the limits and barriers of sound and light. Q&A( tire tread touching the ground )
That's why you turn slightly depending on the geometry of the streets. Not only do you lengthen the distance and appear to go slower they measure your sideways speed not your forward speed
I want a whole compilation video of Neil doing the sound with as many ridiculous things in it as possible....so funny. Every time Neil made the sound, Chuck laughed...Gary just kinda smirked. I find it so funny.
The crankshaft inside the engine is spinning, therefore one side is going faster than the car, but the opposite side is going slower.
Something similar happens with the tires. The part that is in contact with the road goes at 0MPH and the top at 2x the speed of the car.
As for the car parts that are stationary, and the train parts that are moving backwards-even though the respective vehicles are moving forward: Neil is, of course, talking about wheels. Specifically, the portion of the wheel that's momentarily in contact with the road or rail is momentarily stationary. And the portion of the train's wheels that are below the region of contact-the flanges-are momentarily moving backward. Assuming, of course, that the vehicle is not skidding! 🤣
But that got me thinking: Surely there are other parts that are moving backward as well? Depending on how they're mounted, it could be portions of: piston / crank / cam shaft, flywheel, fan blade, fan belt, and any number of valves, actuators, gears, rotors, and internal wheels. I've excluded sound waves, air, wiper fluid etc. since they are not car parts.
You are correct and it all just depends on the reference point from which the observer observes 😮
I would say the very centre of the wheel, that rotates with 0 speed.
There is also a portion of those same wheels that is travelling at twice the speed of the vehicle, relative to ground. This, of course, would be TDC (top dead center for you non-machinists) of the wheel.
@@mikeorr3333Yes, and on train wheels, the top exceeds twice the speed of the train.
@@kilroy1964 barely due to weight compression of the contact patch of the wheel, right? This is like arguing that fuel at 3.999$/ gal isn't 4$ a gallon
Please do a compliment episode on Acceleration Doppler Effect
its sad that you dont understand that the speakers are not there to reproduce the car sounds....
there are no mics from car sounds going to the on track speakers...
I can say this with confidence because I have worked for NASCAR directly, specifically doing things involving sound
the cars are so loud, that you will hear all the dopplars from all of the cars all at once.. this masks the actual dopplar sound so it will sound like one giant roar...they become indistinct
the gaint roar is even louder if you are in the infield as it gets compounded by being reflected off the walls
Doppler shift refers to the change in frequency or wavelength of a wave as observed by someone moving relative to the wave source, commonly experienced with sound and light waves. In the context of sonic bombs, the Doppler effect can create intense and disorienting sounds by compressing or stretching sound waves, potentially amplifying their impact. This phenomenon highlights how Doppler shift can influence not just scientific measurements but also practical applications with significant effects. How might our understanding of Doppler shift and its applications in sound technology evolve with advancements in acoustic research?
17:36 The contact patch between the tire and the asphalt is not going forward. In relation to the ground it is stationary. In relation to the car it is going backwards, at the same speed at which the car is going forwards in relationship to the ground.
The TOP of the tire, at any forward speed, is going forward slightly more than twice the speed in relation to the ground as the car is moving in relation to the ground. the top of the tire is going slightly faster in relation to the CAR than the car is going in relation to the ground.
Tire! That's the answer for your teaser.
Love your show. Thank you so much for that.
good editing guys! we love the more expanatory and visual editing for us
It's the wheels, or rather some points on each wheel/tire that are at the bottom and about to rotate back up... they move backwards momentarily.
I wish you were my teacher when I was young.
Thanks.
Just accept Neil as you current teacher and research as much of his content as you can 😉
Mythbusters did an episode on trying to defeat a radar gun. They didn't find any material you could coat your car with that did the job. Plus, the cops they interviewed pointed out that if they see a car covered in some kind of strange stuff or having unusual things affixed to the roof or something, that is only going to attract their attention more.
So tying the ex up there is not a good idea.
Thanks so much
Love this trio. Hilarious.
The background sounds of the cars are 🔥🔥🔥
wheels. contact point is 0, opposite side is *2 forward vehicle velocity. the tires would break sound barrier at only half the speed of sound of the rest of the vehicle.
Buys Ballot was also 'the guy' who worked out that, if, in the northern hemisphere, you stand with your back to the wind - low atmospheric pressure is always on your left.
Prior to weather radar and weather forecasts this was most important to sailors & aviators.
We need that episode soon....
I always enjoy these explainer's. Thanks guys
We tune 10-20 khz to receive low earth orbiting amateur radio satellites and the ISS, and tune down as it approaches and continue tuning below their transmit frequency until Loss of signal because of that earth curvature.
I would love to see a episode on the science of F1/racing
Circuit of America, Austin TX remote to Boca Chica. Yeh!💓
They don't do that at every track. Atlanta motor speedway is one of the fastest tracks, and now, they have the same rules as Daytona so they're going the same speeds, it's a wonderful sound to really experience. And than, you can hear the cars engine noise bouncing through the infield off of other things, buildings, haulers, hearing THAT specific sound is so weird, you can't pinpoint where the sound is coming from until you've experienced it for a few times.
Neil. Please do an explainer on "Why it is Hard to detect earthquake". Please.❤
Question if you were in water and you make a wave and then make a stronger wave behind it that is strong enough to catch it it makes the original wave stronger and faster do sound waves work the same
Yes, sound waves work the same way. Even light works the same way.
We always learned in high school about doppler effect with the sound of Ambulances
Which is wrong because sirens _don't_ demonstrate the Doppler effect. Siren on emergency vehicles-ambulances, police cars, fire trucks etc.-do _not_ emit sound at a constant frequency. They are specifically designed to continuously vary their pitch, tone, and overall sound pattern in order to grab everybody's attention. So, regardless of whether it's stationary or moving relative to you, you're going to hear the siren's pitch change constantly. It's _not_ due to the Doppler effect.
And yet, so many people mistakenly use ambulance sirens as an example of Doppler shift. Sad 😢.
@@nHans yes the pitch changes as well, because averything is subject to doppler effects. I live in a enormous city where one airport is far away from where most people live, and another is one where the aproach is made over sea. Couldnt use that as an example
ruclips.net/video/imoxDcn2Sgo/видео.html
@@nHans you are confused nHans and spreading misinformation. Moving sirens are affected by Doppler Shift. I understand what you mean; siren pitches vary purposely but those patterned sequences are affected as a whole as the siren approaching is higher in general pitch and lower as it leaves or moves away from the listener. Please apologize for misunderstanding and misinforming anyone else you have made this reply to.
@nHans was confused and misinformed you in his reply. You learning about Doppler Shift with an ambulance siren as an example is fine as long as you understand the shift of its pitch as it approaches then passes and goes away is the affected sound of the siren due to Doppler Shift. Good day!
@@stevemccoy6434 Nevermind that. I wish there were more kind people like you in the internet nowadays - the problem is is my city that was the only sound loud enough and common enough to be used as an example.
Apollogies very well accepted!
That InO on the south runway of LAX was the closest one to my work. They redid the parking lot so the drivethrough could have 20 cars without clogging the road in front of the small park across from it. I got tired after working there for 10 years with the planes landing that I got annoyed with someone holding up the line of cars that I honked at them when they didn't move. I'd gotten used to Airbus 380's and Boeing 747's landing that I didn't care anymore.
The part of the car/train that isn’t moving is the contact patch of the tire at any given instant
I have a suggestion/question(s). An episode based on the view from Mars while on Mars and other benefits of living/working on the red planet. Could Mars also be used to build and launch light sails or give us more access to our outer planets with a large land based telescope? Less gravity and open space for lasers would give it some advantages. I'm also curious about why we didn't explore the idea of landing a fixed object onto Oumuamua. If we can land objects on a comet what's the difference of adding say a video feed and tracker onto a interstellar object with a lander module?
Well in order to land on anything without just smashing into it. We would need to match its speed and direction pretty close. We have nothing currently that could have matched Oumuamua speed and direction.
In 2003 at Charlotte Motor Speedway you could have gotten your pure Doppler shift sound. I haven't been to a race in a while, it may be different now.
Go over drifting next!!! The science in the steering geometry and unique corner G's is enuf alone! Let alone how the suspension is made to continue to accelerate when sideways!
Neil can you please do an episode on the missing Malaysian B777.And how Immarsat used the Doppler shift of the pings of the Engine motoring system to determine its final flight path? .Thank you.
Ironically Gary's bad joke created a very funny moment, therefore Gary should tell more jokes because it adds to the humor big time haha
My mother lives near that In-N-Out. She lives near LMU. That is where I grew up in the 1960s and 1970s before the In-N-Out was there.
Hello Dr. Tyson. Could space crafts be propelled by sound? Enough to where it could make an impact on space travel/maneuverability?
No. Sound only travels through matter and sound ends when molecules or atoms cannot touch each other directly. No sound is transmitted in the upper limits of the atmosphere, or in space.
Residual heat may be radiated by sound interaction, but that effect is not directional enough to propel a vehicle, nor efficient for the amount of work done to produce sound.
5:27 Then I recommend a rally event! Those are as authentic and raw as possible! Just don't stand too close to a turn or a jump, that is not safe!
I have been to that In-N-Out burger next to LAX many times, enjoying the burgers and hanging out at the little park across the street enjoying the great views of the airplanes landing at LAX, it's especially awesome when you get to see a 747 or an A380👍🙂
Definitely enjoying those Doppler sounds from those big airplanes arriving and the turbulent air sounds trailing behind them✈👍🙂
Another amazing video!
Indy 500 1976. I was 8 years old riveted by the Doppler shift at high volume of the race cars screaming past with that 💥 the moment they passed in front of my ears, with the vibration passing through my whole body. Speakers at Daytona sounds very disappointing.
That part moving backwards is part of the wheels.
NEIL PLEASE ANSWER ME: JWST has detected galaxies far more developed than predicted in the begining of the universe. Can it be that TIME ITSELF has beeng stretching too and thats why we see those galaxies as so developed? Maybe time itself on that early universe run at a different speed from ours? A Time´s Dopller Effect? I CAN NOT SLEEP THINKING ON THIS
I used to lay on a grassy street divider that used to be where they built that In and Out… snd film jets landing directly over me. 😊
The part of the car that is not moving forwars must be the part of the tyre that is in contact with the road.
9:25 Ok, Neil, Consider This!!
Two orchestras on the same train but on two separate flat open cars:
Orchestra #1 is closer to the direction of travel or 'front' and orchestra #2 is trailing.
If Orchestra #1 plays a note .. and Orchestra #2 is told to listen to Orchestra #1 and play the same note .. Orchestra #2 will end up playing a higher note, because even though they are not traveling any closer to orchestra #1, at any instant while they listen, they are traveling toward the LOCATION where the note was produced!!
If Orchestra #2 plays a note, and #1 is told to listen and play the same note, #1 will end up playing a lower note, because at any instant while they listen, they are traveling farther away from the location where the note was produced.
The portion of tires on on the ground is not moving at all.
What would it take to break the speed of sound under water?
1500 meters/sec. Just a faster speed is all.
Nobody has commented for a year, but I’m hoping someone can answer this question. I get that the sonic boom occurs right at the speed of sound due to all of the soundwaves being stacked on top of one another. But why is there still a sonic boom when traveling faster than the speed of sound?
So the thing that occurs when we break the sound barrier that we can see with moisture in the air blasting like a wall being traversed, what will occur when we succeed in breaking the light barrier? Light will be blue shifted in front, red shifted behind, like it is with galaxies and then... what? Do we have mathematics that describes this effect or have we used photon waves subbed in to sound wave equations?
This is when the calculator displays "Error." We have no specific equations for proving this because nothing breaks the speed of light. You can only change the medium to something in which light travels faster, or find a wormhole-style shortcut that eliminates the distance between two points. The blue and red shift you describe is observed in very fast travel but less than the speed of light. Red and blue shift are the Doppler effect's pitch change translated into to radiation frequencies. They're how we know the universe is expanding.
The imaginary situation where we could break that speed, however, goes far beyond red and blue shift. All light is seen in front of you - total white-out and no objects can be distinguished. (You're also bombarded by unseen radiations.) Behind you is only black, as no light can catch up to you. This is simplified, but the basic idea as I've heard it presented by some of Neil's fellow physicists.
Chuck, I’m with you my man! 💪 Formula 1 cars arguably create the best doppler effect there is on the race track. 7:25
I'm assuming the part of the tire that's in contact with the road at any given time is not going forwards.
If you were strapped to the front of a plane flying under the speed of sound but accelerating, when breaking the speed of sound would you suddenly stop hearing the plane? That has always made sense to me but never quite been sure
You would definitely not hear the plane through the air, for two reasons. First, the sound waves are all behind you and can't move faster than their own speed limit. Second, your eardrums would have burst, likely before the sonic boom crashed trough your body. The latter may cause internal damage if you're at the focal point of a supersonic plane, but understandably no person has been put in this situation. (Sky dives that go supersonic don't have as much "boom" as a plane.)
That said, if the air pressure is removed from the equation as far as your hearing is concerned, you would still hear the rumble of the plane vibrating from the metal then through your body; more so if your head is in direct contact with the plane. The skull is a great sound conductor.
"I think Chuck is jealous of my doppler shift"
It's so funny when Chuck laughs at Neil's sound effects 😂
Does sound accelerate or is it instantly “the speed of sound”?
Sound's a vibration in a medium. If you shout, your vocal chords make the air jiggle, which makes the air around it jiggle, all the way to someone's ear which has a membrane that jiggles and gets decoded by your brain as a sound. Sound isn't a thing in and of itself; there's no sound waves in space because there's nothing there to vibrate.
If you string up two cans together, the vibration gets carried through the string. People in space can talk to each other by putting their helmets together so the glass vibrates.
So the 'speed of sound' is the speed at which the vibration gets pushed along in air. The _matter_ can be moving but the _sound_ is a thing generated by motion at a certain threshold, so your question doesn't make sense. Which is fine; now you know.
I like how melody sheep can make Neil & all the other astronomers sing while talking. I really enjoy these videos. They are funny.
So that's why the warning not to go more than 5 mph over the speed limit. Well, well!
These guys are great 👍🏾
All you have to do is ask for the last calibration of the device. Chances are is it not within the time it should be and they have to throw it out.
That only applies to specific speed infractions and won't work with every judge. If they can't prove speed, they can usually still charge you with driving faster than safe for conditions, especially if they saw you hit the brakes when you noticed the cop. (Before the lights were flashing.) This infers _you_ thought you were guilty of driving too fast.
Come do a follow up remote in Austin at Circuit of America's then Boca Chica! Formula too! plus good musical guests. Big DeGrass-Tyson fans as still allowed to share teachings in classrooms🚀
I was just talking to my kids about sonic booms this week and why doesn't the Flash make a sonic boom every time he runs faster than sound
I'm with Chuck on this one. Formula 1 FTW!
As always, Thanks! Just a question, is the little man in space in the intro Neil ?
13:14 Neil Missed it! Gary set him up perfectly. "Buys Ballot"!
Ahhhhhh. That would have been Perfect.
I've been to a lot of NASCAR races in my life, and I have no idea what Neil meant by not hearing the Doppler Effect. If he was in a suite, up high, far from the track, enclosed in glass, with speakers I maybe can see where he's coming from. But if you're outside/up close, the actual exhaust sounds overpower any speaker systems when the cars pass by. Typically at Daytona the cars run grouped together in a draft and if they are far away from you (the daytona backstretch is probably a mile away from the main grandstands) I imagine there shouldn't be much of a noticeable pitch change. Also, the speaker systems aren't used to (intentionally) emit engine sounds, it might just be excess noise getting into the track announcer's mic!
Another great example of what sound a plane makes just by gliding through the air is the Space Shuttle, most landing footage from Kennedy Space Center had great audio of the Shuttle, in the past i would think where is the jet fighter flying overhead but no it was just the Shuttle sound :)
Throw a brick fast enough and you should be able to replicate that sound. ;)
If a cop is running towards your car with his radar - it'll show sum of your and his speed: the faster he's running - the more you're in trouble (:
Also zero-speed point of moving car is the point of contact of wheel and road (unless sliding or drag-racing, obviously). Train "backwards moving part" is part of wheel's rim that is currently lower than top of the rail.
The next episode is going to be fire. Let's just say, it'll be where the rubber meets the road.
That hurricane meme is BRUTALLY hilarious....hope that lady is okay tho....🤣🤣🤣LOL @Chuck laughing at Neil's doppler fx🤣
CHUCK!!! My F1 fellow fan!!! That was so exhilarating just to hear you'd rather follow F1. I was tickled to learn this. Who's your driver/team???
You think Alonzo will win this year?? Will Lewis persevere in achieving his 8th??? Peace to you and yours.
I guess smoke from car is the part that is not moving forward at all and the smoke of train that always move backwards
There is flex in the components of most machines. Unless you invent a device that starts and stops every atom in the in the assembly within the same time reference, all of those individual atoms will be crashing into one another, and pulling apart from one another, on the scales that we design them to handle. However, I am very curious about this stuff, and happy to be wrong and learn whatever i can.