Ultrasound gel does amazing things to sound waves
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- Опубликовано: 31 май 2024
- I was curious about the purpose of ultrasound gel. It's really interesting so I built this wave machine to explain how it affects sound.
Video produced in cooperation with Merck ( / merckgroup . Merck is known as Merck KGaA, Darmstadt, Germany in the United States.
Here's the link to Ode To The Future: curiosity.merckgroup.com/ode-...
Animations by Dom Burgess. His brilliant channel, Every Think, is here:
/ @domburgess
CORRECTION: when I calculate the efficiency of the ultrasound scanner without gel I come to a figure 1/10000%. But that would only be if there was a full on air gap. When pressed against the skin the situation is much less dire. The gel ensures a better acoustic coupling by preventing air gaps etc. Thanks to a couple of comments for pointing that out.
Thanks to these amazing patrons on Patreon for supporting my channel:
Glenn Watson
Joël van der Loo
Website: stevemould.com
Patreon: / stevemould
Twitter: / moulds
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Buy nerdy maths things: mathsgear.co.uk 
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"I'm just in a different moment" - that is gold. Consider it stolen.
Hey! I know you!
My thought exactly ;-)
Great, now after this vid on Tom's channel, you are everywhere!
There are some situations where you probably shouldn't use this phrase. eg. whilst trying to make a baby.
@@DomBurgess Better to be in a different moment than in a different partner
That commentary on the stock footage was the best part of my day.
My favourite part was the pointing. "Look, a baby! Look!" 😁
Oh, cheer up! What the hell with your days?
Left hand: stay still
Right hand: whooo hoo
I love this!!!
My husband and I are both engineers. I think we asked more questions about the machine than the baby during ultrasounds. The tech thought we were hilarious 😋
Brilliant!
@@julialennjastorch2630 I'm a rail engineer (traction and rollingstock) we also use ultrasound on the train axles, we have to check for hair line cracks within the axle.
I believe ultrasound is used for lots of testing purposes in engineering
@@julialennjastorch2630 , I actually wasn't familiar with that application! I know ultrasound is used in a similar way to check the structural integrity of multi-ply materials. For example, it's the only way to detect damage to the inner layers of the carbon reinforced plastics that are used in newer airplanes. I only took one class on the topic in college, so I'm not an expert on the topic. I suspect there must be a different "ultrasound gel" for every new material application.
nice :P
Julia Storch i think the word youre looking for might be appenticeship, or possibly internship (american, but im not, so i dont know much about internships)
There is a saying amongst users of ultrasound that the worse the sonographer, the more gel they use. I practically drown people in it. Brilliant video, sharing with all my scanning friends.
How about a large amount of pressure? Felt like the doctor was trying to break through my ribcage last time I had an ultrasound. (Of course that wasn't a pregnancy related ultrasound, but still ultrasound.)
@@Ravengeno yeah unfortunately echocardiograms and other scans over the ribs can be challenging as bone casts an acoustic shadow so you need to get in between them. Both thin and obese patients present their own problems which sometimes also require a bit of pressure. However a pregnant abdomen is all squishy tissue so rarely requires anything more than gentle pressure
@@MedlifeCrisis I never thought about that, that makes total sense!
Now I want to see someone fill a pool with it or atleast a bathtub.
@@woutervanr Looking quickly I found it for $4-5/L. A bath tub seems to be 100-200L typically if you account for a person in it, so you're talking $400-$1000 to fill a bath tub with it. Maybe can get it cheaper in larger volumes, but idk.
Such a cool demo!
I agree! This isn't EXACTLY analogous, but it's a great way into explaining radio frequency reflected power. Impedance matching is important in a lot of applications!
Grady, your Tuned Mass Damper, Water Hammer and Sand Castle demo deserve equal applause. Subscribed to both channels.
It's Grady! Love your videos my man.
I can't wait to see your video where you build a functional ultrasound unit from tin cans and one of those ioniser things used for misting fish tanks.
Hay Sir Grady, can u make an episode about this too maybe your demo toy about this will be more satisfying😍
This is probably the best visualization of impedance missmatch I've ever seen
Yes. It's a great representation of reflections in transmission lines too.
How about the impedance mismatch between the device head and the gel? Why does that not cause a problem?
@@thePronto It's still better than the mismatch between the device head and air (there's always air even if you press it close)
I'm guessing your wife understands how your head works, or you've been banished to the attic till the baby arrives.
I don't know...... I think he's in the attic now.
I was thinking the babies all grown up. He finally looks like he's well rested.
Nah mate he was banished to the Garage; Hence the Vid :P
"That is not my wife btw...
i don't have wife anymore"
;)
definitely the attic lol
2:32. Pretty sure you could have found stock footage suitable for that scene too.
This is brilliant.
Steve's comment section reads like a VIP list of educational RUclips
@@SteveMould Is the impedance frequency depended? I notice low frequencies penetrate the walls of my house while higher ones less so.
@@fuckyoutubengoogle2 It has to be frequency dependent.
That was an amazing setup and clear explanation. It must have taken ages to put nuts on every stick.
It did! But it's ok, I have podcasts :)
I feel like nuts played a critical role in several aspects of this video!
2 nuts for every stick ;)
@@SteveMould podcasts are a life saver for tedious jobs
@@SteveMould I went looking for it on mathsgear to get one for myself. It looks like it took a ton of work. Did you design it yourself, or did someone else design it?
..."like I do for relaxation"
That right there is when I lost it
*Applause*
Bravo
Same here
Came for the education, staying for the humor. Absolutely brilliant.
Wait, is screaming against a wall a valid method of relaxation? I mean, now I know at least what my little brother is doing all the time...
Idk if he was joking or not about him doing it, but it is a legitimate therapeutic exercise.
If it works that makes it valid doesn’t it?
People believe lots of things work that don't actually.
I assume screaming your heart out is a valid form of relaxation, it's just socially unacceptable to scream as loud as you can.
If you believe screaming at a wall will relax you, it just might, but that has nothing to do with screaming at a wall, and everything to do with your believing it will relax you.
I had an ultrasound on my leg once. They always apologise for the gel or the probe being cold, but they don't say anything about how much it tickles. The person doing my scan thought she was hurting me, but I was just trying not to laugh.
I thought your comment was a joke, but then I realized it didn't say "wooden leg", just "leg.
Was your leg pregnant?
Pilchard Pliskin Ultrasound scans are used for lots of medical purposes: heart action, blood clots, swollen or otherwise abdominal organs, and other uses.
@@pilchardpliskin9381 Sort of.
@@allanrichardson1468 Yeah, I had a DVT.
This would transition very nicely into a video on the piezoelectric effect! Cool for watches, and for Ultrasound.
Oh yeah! That I have never seen before.
It's nice to actually see the reflected pulse flips upside down in the case when original wave is travelling in lighter medium, but stays upright when travelling in heavier medium!
Yea. When you use ultrasound on two different materials, steel with cladding for example. The steel/clad interface will actually refract the angle of sound, assuming you're using angle beam. The sound can switch from a compression wave to shear wave from a change in the incident angle
In a moment of contemplative silence with your wife:
"Well, I just wonder that gel is purely for lubrication or wether it servers some other purpose"
This guy deserves a medal hahaha
"I'm just in a different moment"
I can't explain how well that describes me
Steve, you're great at teaching, thanks
Thank you!
Well done Steve, I'm a Biomedical Engineer, we call them crystals I mean the components which the probe made of, and each crystal actually served both purposes of producing the wave and read the reflection (like a mic and speaker in one physical unit)
These are transducers
Dude, as an electrical engineer who struggled with RF impedance matching, this information is golden. Thank you!
That wave machine thing with the weights on it models electrical impedance mismatch in a transmission line as well as acoustic impedance shown here. Makes total sense but it's still really cool to see it. I doubt many people trying to explain transmission lines use this tool but they totally should!
I'm a radiographer and the explanation of this was 👌👌
I have very recently discovered you and you became my favorite science channel! Your content is so intriguing yet is presented so well and clevery simple. Thank you!💕
I audibly gasped when you added the weights - that was one of the coolest demos I’ve ever seen!!
If no one has said it already, I have been a Lv II industrial ultrasonic thickness testing technician for about 7 years. I'm from Louisiana, USA. The "microphone" and the "speaker" in the ultrasonic probe (it's called a probe) are called transducers. They are often made of synthetic crystals and use the piezo electric effect to transduce electricity into ultrasound and vice versa. Steve just did a video on piezo electricity too. That was a good one! I always wondered how that worked. Keep up the good work, Steve!
Demo Highlights for powerpoints (protip: .gif versions of video run smoother!)
3:27-3:38: Reflected wave
4:20-4:27: Reflect/Transmission behavior of Lo-Z to Hi-Z
4:28-4:34: Same as above, with illustrated graph
4:45-4:51: Same as 4:20-4:27 but with greater Z difference
5:58-6:06: Reflect/Transmission behavior of Hi-Z to Lo-Z
6:08-6:15: Same as above but with illustrated graph
That wave visualization device is brilliant! Did you build it?
Well I put it together! But I bought the kit from an educational supplies website. You can also make one with kabab skewers, jelly babies and gaffa tape!
@@SteveMould I feel like it could be used to get a better intuition for how electrical impedance works but I can't quite wrap my head around it.
@@SteveMould Could you please share the address of the website?
I want to know it too!
Steve Mould would less weight added as representation of the wall not have given a closer representation?
The awesome thing about your explanation is not the explanation itself but the details of information you pass to the viewer that makes you figure out the problem yourself before you actually explain it.
Haven't seen such quality in a while, thank you!
Beautiful demo. In engineering terms, the "speaker" and "microphone" is called a transducer.
That dolphin animation was lovely 😊
Visualizing & conceiving something, is great. Visibly seeing thus perceiving it however, is exceptional. Bravo.
I absolutely love the demo you made to demonstrate partial reflection/transmission of a wave.
The demo is very intuitive.
Thanks for making cool stuff and putting it on the internet!
My first job out of college was at an ultrasound transducer company. Later I designed radios for spacecraft. Impedance matching is critical for both. Your video took me back to both experiences. Thanks - I always enjoy your videos.
Wow, this was very convenient, we just started wave mechanics today and our lecturer showed a very similar demonstration!!
Ours too....
Aweeee, congrats to you and your wife!! 💕💕
I'm thoroughly impressed with the creativity and professionalism you had to employ to make this video. Good job.
Steve, you did a great job explaining the principles that I employ every day at work as a diagnostic sonographer.
So can dolphins use ultrasound to see their own unborn calves or at least the calves in the womb of other dolphins?!
Probably not their own personal calves but yes of other dolphins, there are also stories of dolphins showing a great deal of interest in pregnant humans as well in those swim along excursions. However much that added interest translates to understanding is TBD www.livescience.com/38087-can-dolphins-detect-pregnant-women.html
While I am curious about this, what he said in the video makes me think no. Sea water isn't as thick as a dolphin so there would be the initial barrier between water to dolphin which would reflect the most sound back, which is how they would "see." However, I also don't think we fully know what they can "see" with their ability.
Maybe if they put their head/sensor to a pregnant dolphin and started making clicks they could "see" inside each other since they would be making contact and removing as much of the initial barrier as possible.
Give dolphins some ultrasound gel, see what they do :P
It's not exactly the same, but water is a much much closer match for a mammal's body than air is.
@@rebmcr
I remember visiting a science museum which had an ultrasound machine set up so you could look at sections through your hand. It used a pail of water, not gel, so the impedances are certainly close enough.
They can probably detect abdominal gas as well.
Had to learn about ultrasound and how the gel works for A level physics, really interesting actually.
This was interesting but highlights one of the things that I don't like about science videos sometimes. You put together an extremely well articulated and perfectly illustrated explanation of *why* ultrasound gel is used but what I was hoping for from your title is to hear *how* it couples the two objects.
Been watching you for a while now and I reckon that this channel deserves so many more subscribers! Thank you for the content and I wish you luck for the future.
The attic of your house looks like it's from Mirror's Edge
It is not his house, it is a separate place, a "studio" if you will, just to film videos, at least that is what I took from what he said when he first moved in to the place.
Kinda disappointed that red pipe is the only climbable thing in the room.
PuzzL ooh
when I talk underwater other people can barely hear me but when I tap an object inside the body of water they could hear it from far away.
when I talk I make the air molecules vibrate and then theses molecules transfer their energy to the water losing a lot of energy on the process.
isnt this basically the same?
Worgos maybe they're saying "barely hear" in different contexts, I.e. can hear the sounds but can't understand the speech because we're not accustomed to identifying sounds underwater
I know sound travels faster in water than in air, but I don't know what other properties of water it has that might limit hearing (pressure? Depth? Temperature?). It might be that when you observed this you were in a different position relative to the other person and so it reaches them better/worse
@@Darticus42 with barely hearing I meant how loud people sound under water, ruclips.net/video/jxOzpPJbnTI/видео.html (around 10:55) this video explains what I'm trying to say a much better if you have the time/ care enough, but imagine that his helium is the air in my example, and his air is the water
Yeah, talking underwater is basically air to water to air, not counting the losses in the biological systems. Actually, you should be able to hear much better underwater if your inner ear has been flooded, but you would have to re-learn hearing from the thicker medium.
When I talk underwater other people hear "blub blub blub blub eeerrrrrrrrgh".
@@JNCressey You need to breathe the ultrasound gel and then talk ;-)
Dolphins impart vibrations to air vesicles that can be playful or destructive.
The pistol shrimp has an amazing ability to generate implosion/explosion of sonoluminescence to stun its prey.
It is hard to get someone that is able to explain complex concepts with easy examples. You are a Genius. Thank You :)
Hope people like this come more in this world for filling young people's curiosity about various machines.
I wonder, how do you research these things? Can you make a video where you walk us through the research part? Like behind the scenes or something?
Like if you would watch it
He never explains complex things you can't do research for yourself in 15 minutes even with google ....
Nothing complex enough that you can't do research for yourself in 15 minutes with Google is going to be feasibly packed into a short video that's going to appeal to any general audience.
But if Steve was doing it.......I would watch that!
@@dextertreehorn damn, takes me more than 15 minutes! I must be slow :)
@@SteveMould In the video, you mention that the acoustic impedence would cause the reciever to detect abt 0.01%^2 of the acoustic energy given out. However, since the boundary is traversed the 2nd time in the opposite direction, wouldnt the reciever detect (0.01%)*(1-0.01%) of the acoustic energy?
i screamed at the wall and the only it did was piss off my neighbor :(
Sometimes if you cant relax, making everyone else less relaxed so you appear more relaxed by comparison, is enough.
You have amazing teaching abilities. I could just listen and watch your videos indefinitely.
This is a great explanation. While I was watching my wife have an ultrasound I was distracted by all the measurements they take by clicking points on the images, and got thinking about using machine learning to take the measurements.
I hear his words, but all I can think of is: How did he build that wave mechanism...
Telliria he bought it
What happens if you have a weight gradient?
Ooh, I don't know. That's a really good question.
I'm not sure if you'll observe anything unusual in the 1D case, but in 2D and 3D the waves follows curved paths.
@@H0A0B123 I was thinking about the reflection, but I never thought about 3d, nice.
That is basically what a sound horn is.
It is a good topic: how the sound can be "amplified" in a horn without any source of energy?
Thats a good question, horn loudspeakers behave precisely as such systems. Speakers have a big impedance compared to that of air and thus only 10% of the watts you put into a speaker are said to be transfered to the air, most of them dissipating in the form of heat inside the coil.
If you then load a speaker with a horn the sound waves outputted by the speaker enter a small throat which will have a high impedance, this throat will gradualy flare and open up as they exit the horn, gradualy lowering the impedance until it (more or less) matchess that of air. Thus by gradually changing the impedance between the two mediums you have achieved impedance matching and now the speakers will sound louder without putting more energy into the system.
More on the matter if you are interested: www.grc.com/acoustics/an-introduction-to-horn-theory.pdf
I watch so many great sciency creators on youtube amd you are the most interesting, eye opening and funniest of them all. Keep it up! Thanks for your videos! i always learn a lot not only about what you teach but about being curious and asking questions.
What an amazing channel and what an amazing video. This is such a creative way to explain this concept while still being apprehensible and coherent. You have my sub! Well done!
0:38 That was totally me too when my wife was pregnant with our son! I still haven’t lived it down 😂
the only mistake here (near the end) is that the ultrasound transducer is not transmitting or receiving to the body through air, normally there is quite a good contact/connection, the gell is needed for three things, lubrication, hygiene and to fill the possible air gaps (barriers) and make the connection more stable and removing potential resonance....
I think thats what the video is saying
jetison333 I quite agree. I think it’s quite clear that is what the video explains.
@@jetison333 almost... the emphasis is on the air gap and on the air-skin transitional losses, but there's no word about the transducer-skin contact characteristics....
Indeed this is a relatively small detail, the general physics are correct. My issue is with the simplification via dropping of relevant detail on the same level of abstraction =)
@@AlexNaanou @jetison333 It's a tiny omission, but it's basically the most important fact of the video... The "0.1% times 0.1%" claim is just wrong. There'd have to be an actual air gap between the transducer and your skin, i.e. not even touching you. So as long as the transducer is in contact with your skin, it'll get a semi-decent image. As Alex said, the gel helps by removing small air gaps and reducing resonance, but it DEFINITELY doesn't improve the transmission by a million fold! (as implied by "one ten-thousandth of a percent"). That's just irrefutable.
That's always a pleasure to watch your videos, they're really well made and every subject that you get into is something that I've never heard about before on other RUclips channels and that's so great ! You deserve more subscribers ! Greetings from France 😊
Great analogy, helps us understand why change in impedance causes reflection.
2:31 omg I'm dying lol
1:30 had me laughing.
Nice animation! Who did it?
Dominic Burgess. They're great right! I did the wave overlays.
They're brilliant, they remind me of the calibre you see with Ted-Ed videos or School of Life
When I was working in the heavy industry we used ultra-sound to detect
defects in welding. We used wallpaper past as a connection gel.
This was a short, concise, humorous. informative and thus , for me also entertaining video! Wow, that''s hitting on many levels while keeping things simple; which is what I need most. Thanks for being here/there.
Bruhh I thought the bottle said analgel 😂😂
Thought? Or hoped?
So the people in the stock footage are just watching a gif XD
Revising for my uni waves exam tomorrow whilst watching this and it really helped visualise the idea of impedance! Great vid as always!
The next awesome science channel I've just discovered. I love what you're doing
What happens if I slather my guitar in ultrasound gel then?
You form a single acoustic entity between you and your guitar, truly becoming one with your instrument.
@@c0rtikoZteroids1 Or you sit and write a song about how gooey and gross you feel. Either way I'm fine with. ;)
You could put it between the body and a microphone for..clearer sound?
I believe the correct word is TRANSDUCER.
Steve, this is a great explanation! I am reminded of something:
The gel acts like a balun in an antenna. I.E. it connects two (or more) elements that have diferent impedances.
At the end, the word you were looking for is "transducer". A speaker is a type of transducer. It can be used to change electrical signals to sound or vice versa. Similar to motors/generators, speakers are more efficient at producing sound while microphones are more efficient at receiving sound. The transducers used for ultrasound imaging are similar to a dynamo (designed to be used as a motor and as a generator) in that they are efficient at both producing sound from a signal and converting sound to a signal.
The transducers used for ultrasound are resonant in the low megaherz range (≈ 1MHz- 15MHz if my memory is correct) while speakers are resonant at audible frequencies. The reason for the high frequency is to facilitate producing a high resolution image.
Which brings me to the question this video left me with:
I wonder if the math used to produce an ultrasound image is similar to the math used to produce a synthetic-aperature radar image?
If so, I'd love to see a video on that!
these are my favorite types of videos. I may not necessarily be passionate about physics but the anecdote and interesting explanation (and amazing graphics) help me learn some random tidbit about ultrasounds. its not useless knowledge, it helps me appreciate how incredible and advanced the everyday technology we use really is.
You're portraying the problem as if the probe is made of air. I don't know what material it is, but it has most likely an acoustic impedance higher than air. So the attenuation at the interface with the human body would be a lot less, or in other words: more tha 0.057% of the energy would make it into the body. I guess the story is that the acoustic /coupling/ between probe and body is not perfect, but you don't mention that.
Nah, he probably meant the probe-air-body transitions
Then he should not have focused only on the acoustic impedance difference between air and body. Besides, it is not made clear that air plays a role if the probe is held against the body.
You should considerate to possibility to send drones over the airport to avoid noise pollution :p
Absolutely brilliant as always! I especially love your humor-laced videos; some fun in the realm of science! (still one of my faves is your eye-twitching vid, also related to your progeny!)
You make insanely good content Steve. I always stop what I’m doing to see your videos. Constantly thought provoking
Thank you!
Stop applauding the carpark, screamer boy.
The production quality and the explanations were great!
I love the way you complicated things so simple to understand.
I’ve only recently found your channel. I’ve been binging your videos so much and I absolutely love your humour
The "speakers" are called transducers. Your description is close and does a great job of describing the basics. However, the gel also provides "matching" which put simply is a specific impedance between the value in the transducer and the value in the human body. The same concept is used in RF quite frequently.
Really great explanation of the utility and underlying effectiveness of ultrasound gel and wonderful demonstration of the physics involved.
Thanks for the great video Steve, as a musician I am always fascinated by your videos that touch the topic of acoustics (and so fourth), keep up the good work!
this is awesome. watched a few of your videos. love the way you deliver the fascinating scientific facts.
Well explained,gives better insight,thank you.keep up the good work,loved the video!
Facinating stuff Steve. Love this channel 👍🏾
“Sometimes I’m accused of not being in the moment, but that’s not true, I’m just in a different moment!”
That’s the most relatable thing I’ve heard so far in 2019. Awesome video.
the best demo for sound. loved it.
Fantastic analogy of a complex physical system. Easy to understand and engaging. 👍
Your hilarious dude! And your so good at explaining complex stuff in a super understandable way!
Liked and subscribed!
As an ICU nurse, I use ultrasound machines frequently: mostly, to start IVs and check urinary bladder volumes for retention. In any case, it's very important to minimize air bubbles/gaps in the dollop of US gel applied (ideally, to have no air). It can really screw with your readings. Great video!
This video is such a great explanation, and so funny at the same time 😂. What a great visualization
this video just reminded me with impedance matching circuits in electronics classes way years ago to college time, super excellent tutorial.
I once had an ultrasound scan on my left testicle. I'd found a lump and, after a visit to a GP who _squeezed it (!)_ then reckoned it was "just a cyst", it gave me a great deal of pain for about 12 months or more. Turns out it was actually a varicocele, and being able to look inside my testicle and see how the blood vessels dilated when I tensed my abdominal muscles, flushing out the "melancholic blood" as he called it, enabled me to manage the discomfort from then on. But, like Steve, even though I was primarily there to see what was what, part of me was enthralled by the technology. What a time to be alive!
Nice representation of the waves BTW. I like how you showed different impedances.
This is excellent. I am an RF technologist, and I am going to make my apprentice watch this. I demonstrate the same principle (regarding impedance mismatch) with a slinky. Nice work!
I'll be trying your relaxation techniques today. Thank you.
This video made me TRULY understand impedance matching in electric circuits, and why power gets reflected in improperly terminated communication links... 18 years after I graduated. I always just dodged the analog domain ;)
Great illustration! Thanks!
For the record though, you called these waves “transverse,” but I think they’d actually be called “tortional.” A transverse wave would be waving the central cord up/down and/or side-to-side.
We talked about acoustic impedance and ultrasound in my intro to biomedical engineering class, but I really love the visualization with the sticks on wires.
Nice physics demonstration and explanation. Actually only thing special about ultrasound gel is the viscosity. You can use basically any liquid to do the same job of acoustic coupling, but ultrasound gel isn't so messy.
The "interface" problem is not a problem of human skin, its a problem of air that gets between the skin and the ultrasound transducer.
This is an awesome demonstration of wave impedance. It took me a lot of hard thinking to understand this concept without such a demonstration. If I had this video it would have been much easier.
I work in NDT using Ultrasound and Acoustic Emission. This was a great demo. I really liked the wave generation rig you made.
This was incredibly informative and interesting. Not even sure what this channel is about but it's some great work for sure. Subbed :)