Resonant Frequency - Sixty Symbols

[@TheRealGuywithoutaMustache]

This is the type of professor that I want. Anyone he teaches must be really lucky.

[@NSPlayer]

Is that gintoki

[@lostpockets2227]

My engineering Professor plays a few KZbin videos, and tells us to read our textbooks...

[@AnalogFilmDiary]

He was one of the few lecturers that made my 3 years there bearable.

[@tomharner83]

He just taught you...

[@oldcowbb]

i heard he is really tough grader

[@Erdenshire]

Professor Moriarty is a treasure, I love his enthusiasm!

[@robnorris4770]

Professor Moriarty’s resonant frequency is physics.

[@GravisTKD]

@@robnorris4770 I love this. I hope he gets to see your comment. Granted, all of the faculty might appreciate that bit of wit :)

[@schifoso]

His enthusiasm and passion is intoxicating.

[@SorenVemmelund]

Agreed! I always end up smiling from ear to ear watching him explain stuff :-D

[@snackentity5709]

@@robnorris4770 i bet he has a resonant frequency when he bounces up and down explaining things. i wonder if there is a way to harness that energy

[@lostcause78]

"I'm not going to write down the equation, Brady, don't worry." No, please write down the equations Professor Moriarty!

[@StreuB1]

x ′′(t) + (ω^2)(x(t)) = Fcos(ωt)

[@tabaks]

@Brian Streufert, you're throwing pearls before pigs...

[@GravisTKD]

If even just one person benefits from the sharing of the math, then it wasn't a waste. I, for one, am glad to see it shared here :)

[@U014B]

@@StreuB1 Which order ω is that? ω₀, ω₁, ω₂, what?

[@stephanmantler]

@@U014B those ωₓ are not the ω you are looking for.

[@dhvsheabdh]

Are we going back to the older style of Sixty Symbols??? I love it.

[@pafnutiytheartist]

For the resonance my favourite analogy is pushing someone on a swing. If you always push them at the highest point it is very efficient but if you start pushing on a swing at random phases you use a lot of energy but the swing doesn't do much.

[@Ahmed---f9291]

What's crazy is that I wouldn't even really call it an analogy; literally the exact same thing is happening but electromagnetically!! It's so cool!

[@ChrisLeeW00]

But what if you push it at all frequencies? ie, white noise?

[@noahmccann4438]

Chris LeeWoo I’d be interested to know the answer to that. I would think you’d get the swing to the same peak amplitude as when hitting their resonant frequency, but the amount of energy you’d need to do so would be much larger because each frequency requires energy. Physically I think it would be equivalent to just always holding your hand on the person’s back all the way through the swinging motion, so you’re doing all the work and their natural frequency isn’t helping at all.

[@jupa7166]

@@ChrisLeeW00 Hard to imagine milions of hands pushing the swing at different frequencies, but besides of that lack of imagination, supposing it's somehow doable (maybe some actuator driven by white noise), the swing would choose its natural frequency (and a little bit around it) from which it would benefit the most in terms of energy transfer. Exactly the same thing as with the "penny radio".

[@davecrupel2817]

I think i finally understand why resonance matters so much.... Not even kidding!!! Thank you!

[@sk8rdman]

I always appreciate seeing someone so passionate and enthusiastic about their work.

[@QDWhite]

Highly recommend the M.I.T. Introductory Series book Vibrations and Waves. Heavy on equations, but also great at prose descriptions if you want to skip all the math. In it, once they derive the vibration equation (the differential equation Dr. Moriarty talks about around 5:00), they list all types of different vibrating systems it applies to and what the “mass” and “stiffness” equivalents are for each. Everyone talks about GUT, ToE, GR, and even Maxwell’s equations as great unifying moments in physics, but I don’t think enough people appreciate how unifying the vibration equation is. It gave birth to powerful analog computers long before digital ones started taking over.

[@SnackMuay]

This reminds me of a demo that Matt Parker did. Where he took a jenga tower and moved it back and forth at different frequencies. He had it shaking at a high frequency but it was still standing, but when he lowered the frequency to the resonant frequency of the jenga tower it fell.

[@Petertronic]

This video resonated with me

[@forbiddencrystalinternet6201]

It's just like pushing a swing at the right time, I feel like that was the analogy he was trying to remember. When the pushes come at just the right time it contributes to the overall amplitude of the objects frequency rather than cancelling out like it mostly does at all other frequencies.

[@cheeseinmypocketsvelveeta2195]

Thank you for this. It didn't come to my mind and is definitely the best example.

[@jansenart0]

Okay, kinda crazy how it was Queen's Radio Ga Ga on the radio.

[@dragoncurveenthusiast]

You're absolutely right! I didn't make the connection before!

[@user-hk8yp7cw1v]

Try changing the frequency back and forth through FM and AM at a rate of one station per second or faster and ask questions out in the air...crazy how many coherent responses one gets.

[@klaxoncow]

Ah, I wasn't the only one who spotted that, then. About to come here and comment that, yeah, of all the songs for his crystal radio to pick up, it's "Radio Ga Ga" - a tribute to the magic and majesty of radio.

[@Sakkura1]

It really is all we hear.

[@Sean-ce1hu]

@@dragoncurveenthusiast Bit slow are you?

[@davidwilkie9551]

"Absolutely" best basic QM stuff showing frequency alignment with Probability connection/exclusion, positioning e-Pi-i temporal sync-duration resonance. Learning by doing. The full spectrum structure of the e-Pi-i elemental function is natural resonance driven by temporal self-defining cause-effect superposition of Logarithmic Time Eternity-now Interval Conception. "Perfect"!

[@priyansutank]

5:14 that's what a control engineer would say Force-Current analogy. A one to one correspondence between force-current, capacitance, inductance, resistance to spring, mass and damper system.

[@malayapaul458]

Prof. Moriarty.... Wowwww....... He's inspired me sooo much about physics....... Love you prof..... Love from India

[@themaskedcrusader]

Dr. Phil is amazing. I wish he did more videos. Every time I see a video by him on any of Brady's channels, or his own channel, I get way excited because I know I'm going to learn something interesting in an interesting way. Thank you

[@astropike]

I've just had a lesson about resonance in harmonic oscillators and I'm fascinated that the differential equation is exactly the same in many fields of physics!

[@GasTank87]

Man I could listen to Professor Moriarty all day.

[@scottrobinson4611]

I think the easiest/most intuitive example to understand resonance is pushing someone on a swing. The person's mass and the physical attributes of the swing dictate the resonant frequency it'll swing at. Now you start pushing, and notice that the only way to make them swing higher is to push at exactly the right time, i.e. once per swing, and synced with the highest point nearest to you. Gravity starts pushing them down, and you help by only pushing WITH gravity. If you push them consistently twice per swing, you're pushing once while they're swinging away from you, making them speed up, but then you push them again on the way back, undoing all the work of the first push, and keeping the amplitude at a constant low value. This is the same thing as what phil was describing. Pushing at the same frequency as the person would naturally swing means you're only transferring energy/momentum when it'll increase amplitude.

[@kf160k160]

I wish my teachers were this creative and enthusiastic.

[@gusbisbal9803]

So waiting for your teachers to teach you. They are irrelevant. Go learn on your own. Then you would actually deserve a better teacher

[@jca111]

The songs choices are perfect - Radio Ga Ga explaining how a radio works!

[@yikesQuakes]

Love that enthusiasm, made it so entertaining... As if it wasn't already

[@puncheex2]

Resonances are everywhere. The Prof mentions linear mechanical and electrical systems, but there are also rotating mechanical (crankshafts are built to avoid them), pneumatic and hydraulic systems, even heat systems sort-of have them. They define antenna lengths and sizes, they happen at light frequencies inside the electron shells of atoms, called emission and absorption spectra. Seismic signals result from resonances in the various media they signals pass through, frequencies the builders of buildings try to avoid by making buildings stiffer or heavier. Engineering is the study of how to enhance or avoid resonances.

[@mikefelber5129]

This is a head trip of material, but you're SO entertaining in your explanation I stick through it. I wish you were my physics teacher.

[@cowboyfrankspersonalvideos8869]

Resonant Frequency. DING! Suddenly I understand another level of Edwin Armstrong's superheterodyne circuits!! I've understood the operation but not to the level I do now. Boy, I wish I had had him as an instructor in school. I would have learned so much more.

[@davidgregorygodwin]

I found that jumping on my trampoline is a great way to demonstrate constructive and deconstructive interference. When my frequency of bouncing is in phase with theirs', they receive the energy that I added to the system. Science is fun.

[@EMW_Music]

I love how excited Phil is about literally everything

[@keane6309]

Great to see this man again!

[@JotoCraft]

I like the explanation of pushing somebody on a swing. If you push too slow, you miss them most of the time and you don't manage to transfer the energy you put into the pushing into the swing. If you push too fast, you may push, when the swing is coming towards you, or miss the swing again, as it is moving away from you. In both cases the energy you put into pushing the swing is not used, or even cancels out with the energy you put in before. Only if you push at the frequency of the swing, you manage to transfer the energy you put in optimally and the swing gets faster and rises higher. To me this is easier to understand, then "driving" a rod. But this might be, because I'm not native to English :)

[@pratapsinghkanishk]

Wow, the enthusiasm with which he is explaining his stuff

[@Sharklops]

Seems like a much better analogy would be pushing someone on a swing. If you input energy with a push at the right time (ie, at the resonant frequency) then the swing will go higher and higher. If you instead push at the wrong time you take energy out of the system and slow the swing down

[@acolytetojippity]

to take the example one step farther, changing the amplitude of the laser bar isn't equivalent to changing the capacitence on the radio circuit (though it is understandable why you might think that, as it's the part in both systems that is being changed). the change in amplitude is essentially changing the incoming signal. the weight of the bar and it's stiffness both combine to give the system a certain point where it resonates. that "point" is equivalent to a radio station coming in over the waves. Except that *all* the radio stations are coming in all the time, and changing the impedence/capacitance is adjusting where the resonant point of the system is, trying to intersect one of those radio stations.

[@pedroscoponi4905]

This pairs super well with the videos on resonance in standup maths by Matt Parker. Love it :)

[@bennewland3933]

love this guys energy

[@harleyspeedthrust4013]

i love physics. the equations governing this are wicked beautiful i also love differential equations and math in general

[@nicholashylton6857]

It would have been *_absolutely perfect_* if a station had been broadcasting "The Spirit of Radio", by *Rush.* 🤘🤘🎶🎶🎸🎸 But, "Radio Gaga", by Queen isn't a bad alternative.

[@R2D2internet]

To complete the "comparison" it would be beter to FIX the frequency on the function generator and then CHANGE the rod length, for example, until the maximum laser amplitude is found; that would be comparable to modifying the capacitance of the radio, because the "driving" waves are there on the antenna (as the function generator with the frequency FIXED) but you change the natural frequency parameters.

[@IceMetalPunk]

The analogy of vibrational resonance and electrical resonance isn't even just symbolic: mass resists changes in motion (inertia) while inductance resists changes in electrical current, so that term in the equation is just literally "how much any change will be resisted", without caring what type of change we're talking about. And capacitance is how sensitive the current is to changes in voltage, while stiffness is how sensitive the movement is to changes in force (and voltage can be thought of as the "force" that drives current), so that term is just "how sensitive the thing is to a change in driving force". Which just goes to show, anything that (a) has a sensitivity to some driving force and (b) has a resistance to change will oscillate with a resonant frequency that can be calculated with the same equation.

[@Ojisan642]

Steve Mould has a great short video on resonance as well.

[@Ovni121]

An other way to understand resonance frequency is picturing a swing and someone pushing it. If a force is applied at the same frequency as the swinging, the swing will go higher and higher. Pushing a person on a swing at the moment he's the highest back is pushing him at the resonance frequency of the swing.

[@david203]

The sharpness of resonance depends on the "Q" of a circuit, which is its degree of elasticity or purity. Human cells have very low "Q" (they are inelastic), so they don't have a distinct resonant frequency. Most people don't know this.

[@dakotaschuck]

Y'all are delightful. Thanks for the work you do ✨

[@AdityaKumar-ij5ok]

think an ideal swing going back and forth, if you push at the right time you can increase its angular deviation with the vertical, as your repeated push timings match with that of the swing, so it's periodic motion increases, that's resonance, but I was unable to find this much eye opening example of resonance

[@Bestape]

Reminds me of the Golden Ratio "vanishing point" spiral (Fibonacci Spiral pattern), i.e. a square's natural resonance decay, as well as the feeling that comes from a really satisfying bouldering session. :) Thanks!

[@Telukin]

I could listen to Phil all day :)

[@flamencoprof]

I have held the phenomenon of resonance dear to my heart ever since I was educated to be a telecommunications tech in the Seventies. However, I first discovered the principle at an early age by observing the effects of different rates of movement of my body in the bath. Get it right and gallons are on the floor! BTW I feel he neglects to describe how resonance arises through input of energy at a rate which matches the rate of the intervals between peaks of the natural vibration, thus adding energy to each peak, PROVIDED THE TIMING IS ON THE UPSTROKE OF THE VIBRATION. Otherwise, you could input energy regularly on the DOWNSTROKE and stop vibration entirely. Phase is as important as frequency!

[@ioanghip]

A clearer explanation for how resonant frequency is achieved: Imagine pushing someone on a swing, if you push them at the right moment (resonant frequency) the swing will swing more. If you push them at the wrong moment, they will still swing, but less, you actually slow them down.

[@SapientPearwood]

Phil is right obviously, between undergrad and grad school, resonance has been a crucial part of the physics in dozens of courses. Definitely the first time I have heard the phrase 'the resonance is set by the stiffness of the spring and the mass of the monkey' though... not enough primate based analogies in engineering courses if you ask me

[@l47l]

If only my school teachers were this exited and explained so eloquently.

[@Mikephillips912]

Gotta love that Thinlizzy T-shirt. The boys are back in town! The physics were great too.

[@Ghost572]

This is a really nice way of explaining it, I mean there are some other questions I'm interested in, in terms of electricity being transferred over electrical transmission lines but this video does nail down on what resonance is.

[@skoogy7]

Electrical engineer here. What is your question?

[@staror890]

i love his enthusiasm !!!

[@ryan-tabar]

circuitphile when plz?

[@stanleystriker7065]

Inb4 Brady's too busy and it's the holiday season. 😛

[@ThePharphis]

check out Ben Eater's channel

[@theultimatereductionist7592]

I cannot understand anything without seeing the differential equations and defining systems with boundaries and doing energy balances on them.

[@hobbitsumbarch5743]

Just great how he loves his science

[@thepom88]

I can't believe that physicist's are still experimenting on monkeys. 0:59 Great work, guys.

[@StarkRG]

"I like this monkey." --Professor Philip Moriarty, 2019

[@Bluswede]

Extra points for the T-shirt! For a second at the end of the video where Professor got real animated, I thought there was "gonna be a jailbreak...somewhere in the town"!

[@unipey9668]

What do frequent but short resonances lead to? What frequent resonances that are gradually getting longer? What is the maximum resonant frequency?

[@afmartins666]

This. Is. Beautiful.

[@aerospacenews]

Of course his name is Professor Moriarty. And yes, I mean that as a compliment. He is fantastic.

[@lancegambit9851]

Love the way the radio picks up "radio ga ga"

[@maxgrass8134]

Radio on the radio! Thanks Queen!

[@chazthurgood121]

As I posted on the other video. I hope you guys do a series of videos like this on RF.

[@BothHands1]

love this channel! you guys do amazing work

[@tehwubbles]

I feel he didn't really explain what resonance actually is, only what its effects are. Like others have mentioned, it's like pushing someone on a swing at the right time, or timing a speaker vibrating to constructively interfere with previous sounds the speaker has made that are reflecting from a wall opposite the speaker in an enclosed box. Pushing or vibrating at off-resonant frequencies will not efficiently add energy into the system because some of it will destructively interfere and dissipate the energy

[@EvilPOKES]

The Great Professor hurt my brain when he said "differential equation"... My dad did those when he was younger and loved it. I struggled mightily lol

[@alkostach]

Nice T-shirt. Thin Lizzy really resonates with me.

[@cspann831]

A lot of times I find myself doing micro-adjustments with a hammer. I tried building a crystal radio when I was a kid about the time that little book was written late 60s early 70s. Of course how much patience, skill and resources does a preteen possess and of course it failed. That didn't dull my interest in science and tech though so I went on to photography, astronomy and model rocketry. I see this video now and it fills in all the puzzle pieces missing from when I was ten. What's more is the excitement the good Professor exudes over this seemingly simple subject. Thanks to his exuberance the flame of interest has been reignited in me. One could say that out interest frequencies resonated additively. I wonder if our equations are parallel? Oh yeah I too would also like to see the parallel equations drawn out on a chalkboard.

[@Spellitlikeitsounds]

"And everything I had to know I heard it on my radioooo"

[@no_handle_required]

I would have been so much smarter if I had professors like this.

[@marcognudi664]

This was almost better than the first video

[@stephenstruble5064]

It's funny that you guys made a video on resonance frequency. We just finished extrema a few weeks ago. The resonance frequency is the frequency at which the maximum magnitude occurs.

[@MrJesseBell]

What I want to know is why spiritual healers use this concept to explain how they are able to interact with the spirit world or heal with it.

[@Falcrist]

It might help the description if you briefly explained how radios work with carrier frequencies and frequency or amplitude modulation.

[@GilbertTang]

In 25 years we'll get Tool's next album, 'Mass of the Monkey.'

[@breadfan262]

Adjusting the frequency but not the amplitude...but the amplitude does change at the resonance frequency?

[@tamasdemjen4242]

Precisely! Amplification occurs at the resonance frequency. You can try it. Let some water in your tub, and try to move it around with your hand. If you do it at the right pace (frequency), your hand pushes the water exactly at the same time as the wave is reflecting back from the side, and amplification occurs. If your timing is right, the wave will be so big that it splashes out of the tub. This is called resonance. Now if your tub was longer or shorter, you would have to move your hand at a different pace. If your hand moved much faster or much slower, the water would never splash at all, because the reflective wave wouldn't be in phase with your hand movement. And that's exactly how radios work. There're all sorts of frequencies (channels) present in the air at the same time. When you tune your radio, it becomes sensitive to one specific frequency, and that specific radio channel tunes in. As you change the capacitance, it changes your receiver's innate resonance frequency, and a different radio wave causes resonance (like the splash of water), so you just switched to a different channel. All the channels are present in the air at all times, but your receiver is only sensitive to one at any given moment. That's why they can air all those programs, and you can choose which one you're listening to. And that's how we can all talk on the phone at the same time without hearing each other (although that's astronomically more complicated than AM radio).

[@ethan_martin]

we are doing this in differential equations. very cool

[@sundhaug92]

Well-timed Queen

[@xavierpaquin]

I feel like a have a much better understanding of Moriarty since I learned about his coffee addiction

[@gimlination]

Is this the reason for those crazy videos of bridges swinging/twisting/turning?

[@thebigthn]

You guys should make a Rubens tube. It's a cool way to see frequency and you get to play with fire! You can also play music see the flames dance

[@XEinstein]

System equivalence, as explained in this video, was an aspect of physics that was the most mindblowing to me when I was studying physics. And I'm still wondering if there is some profound, fundamental reason why this is so common in physics?

[@BillySugger1965]

Oh man, there’s just one more step now... Put the solenoid (with an adjustable clamp) at the edge of the table, do you can slide the bar in and out to tune its resonant frequency,. Then drive the solenoid with a complex signal containing several frequency components. Now tune the resonator to pick up each of the component frequencies in turn, and you’ve demonstrated exactly how a basic radio works. Even better if the sub- frequencies are amplitude modulated with a carried LF signal. There must also be higher physics concepts that this would demonstrate nicely too.

[@uncertaintyto117]

I know!!! Thank you for such a great comment! *And* there are very, very close parallels between what you're suggesting and how an atomic force microscope (particularly a multi-modal microscope that works with different harmonics) operates. (Except the cantilever length is always fixed for an AFM.) Thanks again. Philip (Moriarty)

[@aspzx]

Is what you are describing FM or AM radio? Because the desktop radio he built was picking up AM.

[@yackos6451]

Does it work with a multiple of the resonant frequency? Does the ruler resonate at 50 hz aswell?

[@Life_42]

I love how he can do all these experiments in a small rooms with a couple of inexpensive objects

[@RealityTrailers]

Cell phones and cell towers and other cell phone emitters like WiFi, wireless devices etc. also transfer various abnormal human health and personality frequencies into people.

[@Zethalai]

No mention that Radio Ga Ga just came on when the Prof tapped the table? 😂

[@skyepyro7104]

Now that you mention it, that's pretty cool. All I heard at first was some radio blah blah.

[@IparIzar]

This can't be... A video about frequencies without a single sinewave? Nice.

[@JohnnyMotel99]

Hyper speed camera work for the hyper speed Prof Moriarty

[@anglosaxon7806]

so this is why I can pick up radio off touching a powered(i think?) computer speakers input cable? Used to do this as a kid and it tripped me out haha.

[@AuthenticDarren]

I still don't quite get how the tuner actually works on this home made radio. I mean I'm starting to understand the principles of radio but I still feel I'm missing something if I wanted to make my own home made radio from bits and bobs. What bits are doing what exactly and yes could you show us more clearly exactly what to do from scratch please? So we'll know what to do when we're trapped on a desert island and we only have junk washed up from the sea and whatnot.

[@ln5321]

That poster right next to his head at 3:25

[@BA418]

What would the efficiency (Ein/Eout) vs frequency plot look like?

[@Momentvm]

what, what? A teacher wearing Thin Lizzy t-shirt, Rush 2112 coffee mug, Vox guitar amp and Radio Ga Ga song demonstrating radio transmission... all this in a physics lab. I'm SOLD! :)

[@mellowfellow6816]

So turning the dial on your radio receiver is like varying the length of ruler overhanging the table edge

[@szkoclaw]

The resonance frequency wasn't explained in a clear manner here at all. Here it is. Imagine a swing. It moves at one full swing a second when no external forces are applied. If you push it every 1/3rd of a second then sometimes you are pushing it when it's moving away from you (speeding it up) and sometimes you are pushing it when it's moving towards you (slowing it down). In the end, you aren't doing much because some of your pushes act against the other pushes. Now, if you push it every 1 second, at its resonance frequency, then you will always push it when it's moving away from you (at the beginning it might be the opposite but then your initial pushes will stop it). With every push, you are increasing the speed of the swing, transferring your energy very efficiently.

[@mghonamy]

can we determine the Resonant Frequency for my body as example?

[@brocktechnology]

Residence is a pretty easy concept, but what I've never understood about foxhole radios and crystal sets is why does rectifying the signal give me demodulated audio instead of rectified RF?

[@uncertaintyto117]

Great, great, great question! See the blog post linked in the video information. I puzzled over that question for years myself... Philip (Moriarty)

[@JimGriffOne]

Sine waves versus Dirac spikes. Resonance is somewhere in between.

[@atrumluminarium]

The Fourier transform (i.e. frequency spectrum) of a sine wave is in fact the Dirac delta and vice versa. Not really related to what you said but a cool fact. Your "in between" is the Lorentz distribution (Cauchy distribution for statisticians) which determines the amplitude around the resonance frequency

[@tinzend_Jenjooeen]

How does the monkey/spring have a resonant freq, isn't he putting in energy with his wrist and gravity? I don't get what this natural resonance is.