Fire Driven Sound Waves in a Quartz Tube 

I'm curious if the space between each ripple in the flame could be determined by measuring the upward speed of the flame, and dividing it by the fundamental frequency of the tube. I at first was tempted to think that the ripples were another example of "sub peaks" in the sound wave as we saw in the foam bead experiment in part 2 of the thermoacoustic series, but after reconsidering I think it's more likely a factor of the slow moving flame being regularly impacted by the sound wave. Even so there are some curious things to consider, like why does the flame break apart in mid air? That doesn't seem to make sense unless the air movement of a sound wave is subdivided with nodes at the pinching off points. Very interesting to think about.

I see a thermoacoustic pipe organ in the future! Great stuff!

About a decade ago, when I was a kid, you got me into making my own fireworks with your videos on pyrotechnics. Today you're one of the highest quality educational video creator/producers. It's your accomplishment, but I'm proud to have been here watching the whole time :)

5:00... so alcohol is wetter than water? I think this deserves a whole video

Life goals: Find a Significant other that looks at you the way NightHawkInLight looks at acoustic fire

Those slowies were wicked! The flame may break apart in mid air, as nodal points might be compressing atmospheric air and replacing the flammable gas at those points. Really great viddy - and being off script was really fun to watch actually!

What do you think about watching this hot air movement with use of Schlieren Effect? This may give you some interesting results... :)

We DO appreciate your "casual" videos! Thanks for your dedication!

Wow, at 2:45 it sounded like an ocean liner. LOL Singing tubes are very cool. Great work as always!

I can just imagine you either sitting by your computer or in a shop, suddenly going all blank in the face as you see that tube. "I got to have that."

As a musician, I enjoy this a lot. Looked like a ton of fun. Frequencies and vibration have so many interesting effects it seems magical really.

Great video, Love the quartz tube allowing for such a great visual. I especially like the slow motion of the waves. Just curious, what was the length of the tube, did you mention it somewhere and I missed it? Also, it would be interesting to see how the actual frequency measures compared to calculated measurements. They tend to vary according to the temperature of gas inside the pipe. Any experience with Sondhauss tubes? I've dabbled with them a bit but haven't gotten anything near as good as the Rijke tubes.

u can say it has a warm tone to it

thank you for being one of the few people not making an april fools video.

Your videos are great. Thanks for brightening my day.

You're more concise off script than I am on script most of the time

Videos like this where you go off script are cool. It may not be as concise, but your demonstrative discovery is seen and I appreciate that kind of thing. Just look at SmarterEveryDay's new video where they're talking about magnetic worms. It's great to see someone talk unscripted about something they're genuinely curious and/or excited to talk about.

I've been subbed (on another account) and watching your channel for almost a decade now, and I appreciate how well you interact with your community. You are open to constructive criticism and suggestions in a way that most science RU-vidrs are not, and it's very welcome. Keep up the great work!

This gave me an idea: use this effect to make a musical instrument by putting resistive heating elements into tubes sized to produce different notes and control the whole setup from a computer or something

Enjoyed this immensely! Can you imagine When I was in my early 20's, I would take a plastic bread bag, tie it into a number of little knots,all cascading downwards and then suspended it above and over a pan of water. Then record the weird sounds that would emanate from it being set on fire (the tail of it) and dripping the melted plastic while it hit the water. Crazy sounds unlike anything I've been able to duplicate (to date).

Thanks again for that high-quality video! :-)

Wouw! Pretty cool experiment again! The flame's break should came from the node of the sound wave basically so the period near by the typical frequency. The chimney effect is so strong here so I think it could add some traveling wave component to the standing wave. Another interesting thing when the burner was close enough to the quartz tube's wall (8:31) the TA sound effect started with the higher gas speed easily, so I think the gap between the burner's diameter and the glass tube important for the best result. If I'm right than the visible vibrating flame could go much higher in the optimal diameter tube, not just around the bottom. It was a really good demonstration Ben! Thanks to share it! BLADE 👍👌🙂

I believe that since the burner is venturi aspirated the flame is actually very, very sensitive to pressure fluctuations in the tube. It would be interesting to see this done with a burner that uses pressure fed oxidizer.

What caught my attention and interest is the up down, up down effect of the flame. Its like a powerful hypnotic effect.

This was really cool! I think maybe even my favorite video from this series so far...

Thanks for discovering and presenting without a script. In response to your comment at the end of the video about not using a script for this video, I want to say that I enjoy and learn from watching and hearing the discovery process as with this video. It was great!

I'm studying sound design and I had no idea what thermo acoustics were until your video. Now I might just try to build an instrument using it!

I appreciate videos that have the work put into them, instead of churning out something twice a week. This is less labor-intensive than your usual, but it's still way ahead of a lot of channels.

You look so happy In the thumbnail Love it

Your research, writing and other pre-production is super appreciated. Your casual clips are great too!

On the note of musical instruments, there is one called a "Pyrophone" that uses this mechanism. Definitely doesn't get enough love though, so i am 100% down for you / others making one (i will myself one day) (I'll put some relevant link spam below)

Man, has anyone else noticed how good NightHawk's cinematography has gotten over the past few years? These are some of my favorite videos to relax with (like the Tesla Valve video). The combination of visually striking phenomena on a clean background with a smooth, pleasant voiceover is just great, plus learning something interesting is a nice distraction from the world going off a fucking cliff.

It's as if a pulse jet and a bassoon had a baby.

Dude, your channel is huge in content! Such an inspiration! Thank you so much for sharing!

Love the videos, both casual and scripted. Your commitment to accurate, concise, and detailed information is one of the reasons I subscribed long ago (in addition to the interesting topics/projects and the way you present the information and engage in dialog with your viewers

Definitely enjoy the casual videos too! Thanks Nighthawk!

Thank you for the both types of videos I love them all!

I watched many of your videos and I can tell you do a amazing job and great work on casual videos and in-depth videos.I learned so many things. Thank you for you work (From France)

It might be really cool to explore using colored mist or nonflammable dust/smoke inside the tube. You might be able to see where the nodes are positioned along the tube. Also, it might just be cool to see how the gasses and sound waves move through the smoke medium in the tube.

I know I'm about a year after the release of this video, but I've only just come to your channel recently, to see the joy of the science on your face as you demonstrate the experiments is amazing!

You should try attaching a Coleman lantern mantle to the end of the torch. Perhaps the mantle could act as a buffer to prevent the pressure from putting out the flame.

Thank you for visualizing physical processes. This helps to understand how plasma is controlled.

Those transient states are beautiful. I wonder if they can be maintained in a steady state or at least switched through fast enough to give the illusion of being stable.

I think casual videos are great! They’re so candid, genuine and fun! And you deserves easy one every so often at least! I definitely think a combination of some thorough ones and some casual/learn as you go ones is good. Most of the youtubers I watch are pretty casual for the most part...

Idea to film it in the small tube: If you can adjust your cameras frame-rate to almost match the resonant frequency, you could film the effect in the little tube as well (stroboscopic effect). A high resonating frequency means that the draft is very slow compared to the sound, which could mean less turbulences, making the effect more reliable.

The thermoacoustics experiment reminded me of an experience that I'll never forget. In the late 80's, I was a tug captain piloting a 300' barge of full of "cans"...Pilings. Galvanized steel pipes 2', 3' and 4' in diameter and about 100' to 150' in length. The barge heavily loaded and was headed to Alaska somewhere to build a dock. We were coming down the Duwamish Waterway. The last corner we negotiated was called Fisher's Corner as it was a flour mill back in the day. After that corner was a straight shot into Elliot Bay, Seattle. The wind was blowing, prolly 25-30 outta the North. I was piloting the barge up at the bow standing on the pile of pipes. My mate was at the wheel. As we rounded the corner, the wind was blowing across the pipe ends. Like a flute. It was no small task to turn the barge into the wind...but we knew what we were doing. We anticipated. What happened next took us all by surprise. A vibration started that felt like I was being torn apart inside. I'm sure the mate felt it too! Perhaps like a Star Trek transporter. It was very loud. Really loud and deep. I was standing on the pipe but they started vibrating...I basically was forced off. Today I'd die, but I was young and just took the fall...bouncing from pipe to pipe some 20 feet in stride. As I hit the deck, the vibration was making the dust and stones bounce. I couldn't see or breath. It was like standing on ice. The mate was yelling in the radio asking what was going on! When I spoke in the radio he simply couldn't hear me. We were driving blind! The mate knew he needed to turn and by guess and by golly he turned the barge straight into the wind and the vibrations and noise went away. We made a bunch of smart ass comments to each other and then went about our business. We were both pleased we didn't make the news by crashing into something expensive. It seemed to me, if properly tuned, those pipes could have destroyed our barge.

Im reminiscent of a pulse jet when I watch the high speed video, any chance there's some similar mechanics going on here?

I just came across this channel, and I love the look of satisfaction and joy that he gets when his demos are working well :)

This is a really interesting topic. I hope we get more videos on thermoacoustics. April Cool's Day amirite?

I really like these 'unscripted' videos, It shows your enthusiasm about the matter.

whaaaat, not even an april fools XD, apreciate it

Pure awesomeness! Thanks for being here!

Is that almost like the same concept that makes a pulse jet work except it is naturally occurring without reed valves?

I appreciate your ability to simplify science and explain things well you must be a teacher

I hope you end up doing collaborations with The Action Lab, Technology Connections, NileRed, Cody's Lab, Backyard Scientist, Keystone Science.

Love every video you put out. Can't wait for my kids to get home so I can show this one to them. We re-create as many as we can - it's such a great way to foster their love of science, creativity and curiosity!

I'm surprised you didn't use this as a moment to Rick Roll your followers or something for April fools day.

I remembered seeing a fire extinguisher that used sound to put out fires...Yes, just looked it up again, easily found by search engine. The sound waves extinguishing your flame is essentially the same thing. Great demonstration, Thank You.

I can't believe how many science videos Post Malone filmed before getting face tattoos. They're all so good, too!

Bruce Yearny and Yourself are excellent at what you do, thank you as always 👍

I will have nightmares about vibrating Quartz shards plunging their way into your eyes, KEEP YOUR SAFETY GLASSES ON DAMNIT!

Im really loving your latest projects!

Gives me tuning fork vibes. I could legit sleep to this. I love the way the flame is effected. It's beautiful and neat to see sound waves like that.

I do really appreciate you transferring this knowledge so efficiently!

Yes, I do appreciate the casual videos. maybe not quite as much as the more intensive ones, but I think sustainability is important and the casual ones are definitely still in the good enough to keep me clicking them and watching to the end when I find them in my subscriptions page (yes I actually still use it).

Your experiments have me pinned to my chair. Thanks for your hard work.

I just wanted to tell you that your channel is one of my primary research sources for my sci-fi blog.

I discovered your channel by RU-vid suggestions and i must admit that a very good discovery. Thank you for your passionate and honest work and keep teaching us about physics.

Brother, I love your curiosity and your attitude! I am grateful that you offer these videos and share your experimentation! Frequency and electromagnetism is what it is! I thank you kindly and salute you! Three cheers!!! Keep it going! Just found your channel and am loving it!!!

Best opening ever, playing/flexing with a big burner on your work bench! Also, these topics are extremely interesting! Please keep doing what you're doing!

Thank you for all that you do, please never stop creating and teaching me about really cool things!

Your content always humbles me on how much I don't know. There's always something new to learn!

Its very interesting that, when the tube is lit, how the flame gets those characteristic flow waves. I would believe that is the frequency. Its interesting that you can see the way the sound sort of propagates throughout the flame. Very good video!

Great demo of the phenomenon. Seeing the flame affected by the sound waves in slow motion was super cool.

I do this demo with my physics students every year. You’ve shown me a neat modification of coloring the flame and recording it in slow motion. My students are going to love this modification. Thank you for your hard work and sharing your knowledge and passion.

I'm a biology student but I really love this experiments that you do❤❤❤

I wanted to say, and I think a lot of people will agree with me, We appreciate the content, regardless of the format, prep time and post processing. Of course the effort that goes into the more polished videos is noticed, and greatly appreciated, but any content is enjoyed, regardless of the final production value. I believe if you think about it, you can tell that, not only from the quantity of people that like your videos, but from the quality of the people who await your next videos with great anticipation. Many of the biggest names in the youtube world are some of your biggest fans.

thats so cool that you can see the transverse wave in the edge of the fire, I didn’t think there was a way to visualize it outside of oscilloscopes and rolling shutter tricks on a guitar string

The enthusiasm and joy is just amazing

we appreciate all the work that goes into these

I really like the content that you put out and the depth you go into. Thank you for the time and devotion involved

Very cool! Excellent layout, setup, science and photography!

Amazing video ,you are inspiration for me

Hey Nighthawk! Thanks for the awesome content and the learning you share with your subs! Our channel is not as refined, but our family really loves Visual thought experiments as well. We have not stopped creating, but low on our upload frequency rate. Hope you continue to share candid videos as well as the scripted! #sameteam #scienceisFUN

I do appreciate all the effort you put into your videos.

All your videos are highly appreciated sir!

Off-script video was really enjoyable. Both the more casual and the more scripted are good, keep both up :D

Absolutely love all of your videos! They are as informative as they are enjoyable to watch. The acoustic resonance gets me back into pulse jet train of thought.

Fantastic content. That slow mo footage made me happy. That tube is freaking awesome!

I love the wonder on your face when you do this stuff. It's obvious you love exploring and discovering new things. It's always a pleasure to make the journey with you once in a while. Thanks for being you! :)

This non script is an awesome format too! Thank you for all the exciting experiments and explanations =)

Bruce Yeany is great. ive followed his videos for years. love seeing this in slowmo.

Totally discovered this in highschool with 2 very large cardboard tubes. It was so loud enough to shake the windows in their frames and the entire school heard it. Free period in advanced chemistry was over shortly there afterwards..

I like the new format. This thermoacoustic stuff is beyond beyond.

I enjoy the casual videos just as well, if not more.. The casual videos seem like you have more fun. And that is fun to watch.

Nothing short of fascinating! You rock dude, thank you!

Your content is always awesome regardless if you are off script or not... Thank you for your efforts it's very much appreciated

Fascinating! A very interesting explanation on why the sound causes the flame to extinguish can be found by the video the The Action Lab recently did on a phone app that blows out a candle.

you know what, i do appreciate your videos, all of them!

Beautiful footage! I always interpreted this demo as the sound wave first pulling fresh air into the combustion zone, getting a little boost from the resulting puff of fire, then pushing the fire back down into the flameholder on the return leg (hence the disconnected puffs of flame in your slowmo). Basically it's combustion-amplified audio, which could make an incredible sound-and-fire instrument if you could tune it!