I don't *think* it can be used to make a logic gates, otherwise you know I'd be trying to make a binary adder right now. The sponsor is Jane Street. Check out their opportunities bit.ly/3vpLNVW

Never thought I'd see an analogue loading-screen icon.

Every engineer in the room: "I'm definitely a responsible adult"

Kudos for the originator for recognizing that this was cool enough to tell Steve about! It is so cool that he just happened to make the size of channel that can produce this effect. If he was using smaller or bigger jars then we may all have been oblivious to this.

I love how this channel has Steve talks about things like "I'm not exactly sure it's cool, but here it is", and gradually it gets better and better, until you realize it *is* pretty awesome! 😄

If fluid clings to track, Moebius strip

Physician here, found an interesting parallel to a cardiac arrhythmia in one of the models. At <a href="#" class="seekto" data-time="626">10:26</a>, the small loop of the ‘flame splitting’ model starts its own circuit, increasing the activation rate of the larger loop. This is very similar to the cardiac arrhythmia ‘AV node reentry tachycardia.’ The cardiac conduction system is also an excitable medium that meets the 3 criteria mentioned my Steve in the video. This flame model could be an interesting was to demonstrate or study this disorder. Thought this was interesting and wanted to share. Thanks for always making interesting and stimulating content, Steve!!

Just found out, men are excitable media: "the first is that after it has been excited, it can't be excited again right away. The second characteristic is that after a certain amount of time the medium is once again excitable." Made me chuckle way too much for my age. Love the vids, you're amazing, Steve!

This concept is actually very similar to the principle that is used in rotating detonation engines. These are engines where the flame is supersonic (so a detonation instead of a deflagration) and the detonation travels in a circular path continuously. You should do a video about those. They're super interesting.

I'm a resident doctor and this made me think of all the ways this shows up in our bodies--specifically the nervous system. The "split" track that sometimes feeds back on itself and creates a self-sustaining mini-loop is a wonderful model of how some very common heart rhythm issues develop!

"Excitable Mediums" sounds like a great business name for a REALLY extroverted fortune teller.

Not only is the material fascinating, but the presenter's communication style is very easy to understand and very pleasant to experience. What a combo!

I feel like this is the beginning of something, and I’m really glad to have been here for it

The idea of a constantly rotating forest fire all the way around a planet was a major plot point in the book "the player of games" by Iain M Banks. It's a good book, I recommend it.

Forest fire loops may not have been observed, but there's a known phenomenon in high-elevation forests in my part of the world, called 'fir waves' (check Wikipedia). The excitable state is fir trees' susceptibility to wind damage and desiccation, and the refractory state is when the tree is short enough to be protected from damage by its neighbours. There's a period of about 75 years, and alternating bands of fir trees in various stages of development are observed on the slopes of many of the mountains around here. The bands propagate slowly eastward, in the direction that the prevailing westerly wind blows.

Loved that shoutout to JK Brickworks, a Canadian Lego Legend!

Silverstone or any other race tracks would be interesting to see. If fact, would the flame cope with more technical tracks? and what in the longest you could make the track? as the Northcliffe would be interesting too (but maybe a bit big to print?)

From water themed videos onto Steve's flame-starter era.

This is basically how Rotating Detonation Engines work except the wave front is supersonic and therefore compressing the gases, removing the need for a compressor The circle with spokes is like a RDE combined with pulse detonation engines lol but great work!

Super interesting! thanks for sharing. That endless loop is cool, but I think my fav was that one that split because it started to light at random spots and go all wild. Very cool!

Reminds me of the "Super Kamiokande" experiment, a huge vat of purified water completely surrounded by 11,000 large (50-cm), custom-made photomultiplier tubes. It was designed to detect flashes of light from rare events like proton decay and neutrino collisions. The tubes were evacuated glass structures, and when one imploded one day, it triggered the implosion of its neighbors, and, well . . . regeneration time was better than forest regrowth, but not by much. "Super Kamiokande 2" had acrylic shields between the tubes.

You just figured out a phenomenon, that I think is being developed right now in rocket engines. I got a friend in engineering that told me they are working on an engine design with a flame spinning around, gets 30% more efficiency as of now

if only people could figure out how to harness the power of combustion

About 1974/1975 I wss at the University of Texas at Austin. Ilya Prigogine was there with his group and they were studying chemical clocks, and chemical oscillators. Now Prigogine got his Nobel prize in 1977 for a range of things with names like "dissipative structures", "systems far from equilibrium", "internal self organization", "irreversible thermodynamics". My point is this kind of play with periodic and repeatable phenomena is the stuff that might lead to a nice prize, or something like a new engine or battery design, or a new toy that makes more money. Now I was going to send this and I remembered "tornadoes" and "solitons". Those self sustaining structure can remain stable as long as there is energy available, or there is no "dissipation". The non-linear Schrodinger equation can lead to solitons and stable states of the vacuum can form matter. I STRONGLY encourage you to devote time to models and and equations. The models (like your game of life) are much easier to play with than symbolic math because a model or digital twin will "do something" and most math still requires the human to do all the work - by hand and memorization. I remember UT fondly and often think of the nuclear fusion group there. They were really excited, then they seem to have given up. But "self sustaining reactions" take on new meaning when one solves the same kinds of models, the same kinds of hints from mathematics -- for nuclear reactions and nuclear fusion propulsion systems. Look at the Wikipedia article on "reaction-diffusion systems". and you will see "traveling wave front" and other useful starting points. Filed as (Self sustaining reactions, solitons and Nobel prizes, wave fronts, atomic and nuclear space ships) Richard Collins, The Internet Foundation Yes, it can be used for computing.

I am sincerely so grateful this channel exists. Thank you so much for every one of your videos - they all blow my mind, and make me want to learn more

You can create one-way tunnel - it is a step which is short enough for the flame to go up, but high enough so it cannot go back down. You can put it in the generator loops to stabilize them. You have a non-connecting crossing already in the 8 symbol and a a splitter. The only missing part is the NOT gate and we can have a running flame computer with no moving parts and no electricity.

The beauty of the rapid prototyping afforded by 3D programming, especially when paired with the ability to parametrize in CAD, is so very well demonstrated, here.

I'm constantly in awe of Steve for pointing out something new that actually exists and is typically fixed in the changelog for the following month.

The way Steve says "..in other words- people like you." really spoke to me

Always amazed at Steve highlighting yet another thing in actual reality that you'd normally expect to find patched out in next months changelog.

Can I just point out how cool it is that 3D printing has gotten us to a point where someone discovers something and he can help you investigate simply by sending some files? No guess work, no shipping parts, just “Send me the files” and you’re ready to investigate.

Its essentially an equilibrium flashpoint simulator

That viewer deserves something. I am happy for you Steve what a coincidence , and awesome testing! You are really onto something there

With a much more intense flame, this concept of a constantly replenished flammable gas mixture being an excitable medium is also the basis for rotating detonation engines, where you have a detonation wave racing around in a circular channel that has an air-fuel mixture continuous fed into it from one end

"The Player of Games" by Iain M. Banks features a planet where there is a worldwide forest fire with a predictable flame front travelling around. I can't recall whether it is permanent or periodic, but this video reminded me of it and now I'm going to have to reread it. Again, for probably the 10th time.

Fascinating. Thanks for sharing this observation and your experiments, Steve.

I absolutely love your channel Steve, no matter what, you always have something interesting enough to take the mind off of the more stressful elements in life.

One of the most fun examples of excitable mediums in chemistry is the Belousov-Zhabotinsky reaction. Shoutout to NileRed on that one.

To me this incorporates the real essence of science. You discover some weird anomaly, and you keep drilling down and drilling down till you find the answer.

This is one of the coolest channels on youtube- the concepts you introduce always get me exited like I'm a kid again!

This was very cool! Can always count on this channel to introduce me to things I never knew existed and/or had never even thought about before!

The endless forest fire is actually a plot point in the Scifi novel Player of Games by Iain M Banks. When you mentioned it I was pointing at the screen like "OH OH OH I READ ABOUT THIS CONCEPT"

I'm glad you mentioned heart fibrillation because the rest of your description of the burning cycle was making me think of the heart contraction cycle as well. Even the way the cardiac cells have a "refractory period" as they re-polarize between beats is very similar.

This is one of my favorites, so glad you were introduced to this idea. I've seen it in action myself. That was really fun.😊

I've honestly never been so invested in watching a flame going round in circles. Utterly mesmerising and amazing to learn the reasons behind it. Fantastic video!

Don't forget what you said at the beginning: it's not the lighter fluid that's burning; it's the vapor coming off it. The raised part of the figure-8 trough is probably getting some vapor from the part directly below it.

fluid dynamics, physics, chemistry etc. very informative and helpful in understanding the world around us 🧐

Steve touched on it with the heart fibrillating, but it also happens on every heartbeat, and we can use EKGs and EGMs to locate the source of arrhythmias and burn them to break the circuit, restoring normal heart conduction (usually permanently). If this type of thing interests you, I highly recommend researching EGMs and arrhythmia mapping. The design where the flame splits and reconnects resembles a re-entrant tachycardia. The circle with legs out of it is similar to a micro re-entrant tachycardia. On the augmented spiral, you can imagine a re-entrant tachycardia forcing an unstable rhythm, where the ventricles beat too quickly to fill. Blood pressure will slowly spiral down until the coronaries are unable to perfuse, eventually leading to cardiac arrest if the rhythm isn't returned to something stable.

I just wanted to shout out Iain M. Banks' great novel "The Player of Games" which has a planet with a perpetual forest fire around the equator, resulting in the planet having fire seasons and regrowth seasons. I always thought that was such a cool concept.

I'm thrilled at the interest in this subject, flames and plasma are fascinating

Genuinely enjoyed learning about this. Simple looking to make, above my simple mind to fully appreciate, and so cool to watch.

I used to make similar chasing flames 30 years ago or so, simply drawing designs in lighter fuel on concrete pavement and the flames would chase back and forwards around the drawing.

Your track at <a href="#" class="seekto" data-time="616">10:16</a> is actually a really good stand in for a medical phenomenon called AVNRT. It happens when the heart has a re-entrant fast circuit at the AV node in the heart. It similarly fires new beats down to the ventricles and up to the atria just like that track. It was really quite cool to see a physical interpretation of this when I’ve only ever seen animations or illustrations of it.

Absolutely fascinating - thanks for sharing 🙂

Thank you good sir for sharing this knowledge.

I actually saw this exact same effect with the brandy around a Christmas pudding years ago and I'm so glad to finally have an explanation.

one thought about the fluid not draining away from the raised section on your "figure eight" track: maybe the layer lines produced by the 3D printing process helped the fluid cling to the track by creating tiny steps that the fluid could pool on easier(thanks to surface tension, maybe)?

I love this more than anything right now. And I need this in my life on the backyard patio I don’t have.

It is truly amazing how after all these years you are still able to give me and answer questions that I never had😅

I discovered this as a middle-schooler with hair mousse in the bathtub. You can draw any design and the flame will travel as the mousse bubbles pop with flammable gas. Easy cleanup and rapid iteration on designs. My favorite was a pentagram/pentacle as the various intersections would launch out flames as rapidly as the refractory period would allow.

Very cool. It immediately brings to mind the concept of rotating detonation rocket engines.

Wow! I’m in advanced pharmacology right now and In the beginning of the video I was immediately reminded of the myocardium and “his-purkinje” systems as it relates to the calcium channel blocker’s effects on the purkinje fibers. Then, when you mentioned heart fibrillation at <a href="#" class="seekto" data-time="448">7:28</a>, I felt compelled to tell you that I agree with your hypothesis!

Cheers for making these kind of video's. Its always a highlight to see it. Keep doing your magic mate🫶🏼👍🏼

Unless I'm just missing it, I'm really surprised that I haven't seen anyone mention those old falling sand games. The whole idea of an "excitable media" immediately reminded me of them. Sometimes called "Pyro Sand" or something similar, you can play with different materials that have different interactions with each other and different reaction speeds. You could create "emitters" each material, and I spent many hours playing with the the differing wavefront speeds to try to create stable reaction cycles.

<a href="#" class="seekto" data-time="442">7:22</a> ive never seen a more perfect rendering of the patterns that sometimes happen when i close my eyes

Now you just need to figure out a way to have the lighter fluid replenished as the flame goes, so you could keep something like that running indefinitely.

Great video. You can, and should, make a spiral loop! It just needs to have a u turn in the center and return tracks in between inwards going tracks.

Dang, this is an effect I've seen a million times in a non looping shape. Kinda bummed I didn't discover the artistic potential myself as a teenager when I was burning patches into my desk instead of doing my homework. I haven't watched the whole video yet to see your explanation, but I suspect it's a fairly simple matter of the flammable vapor entering and exiting its combustible range in air. Once ignited the vapor and oxygen is quickly consumed in the hollow of the print causing the flame to extinguish and progress to a new area. By the time it comes around again there's been enough time for the vapor and air to freshly mix and the burnt exhaust to clear out.

For responsible adults only?..... I'm out...

by far the most unnecessary but supercoolest thing I have ever watched!!! Thanks so much for lightening up my life

Thanks Steve, helps a lot!

The motion at <a href="#" class="seekto" data-time="612">10:12</a> with the split pathways model is very reminiscent of Wolff-Parkinson-White syndrome, if you imagine that the smaller circles are the heart ventricles, you can see how a pathologic pathway will reexcite the heart way faster than it takes for the normal route to come around, very interesting to see!

Love that this phenomenon was encountered quite accidentally and then explored so thoroughly. Well done. New sub.

Fascinating! I'd love to try a design with Hilbert space-filling curves

You always find some of the most interesting scientific oddities, Experiments principles etc.

My first thought would be to replicate various F1 circuits. Perhaps a flame trough Monaco can be a more compelling procession than when the cars are on it.

This is so cool Steve! Notice something: when you had that sustained flame at the junction, it lit the traveling flames at a pretty consistent interval. I bet that represents the optimal vapor/Oxygen ratio to support ignition for the given vaporization rate for the surface area exposed. Neat!

So totally cool are these spiral flames...mesmerized!

<a href="#" class="seekto" data-time="700">11:40</a> Congratulations, you have achieved perfect uzumaki chakra control

This happens every year with my Christmas pudding. We light a ladle of brandy and pour it over the pudding. The whole thing burns for a while, then it's just the ring of brandy that pools on the plate around the pudding. It usually reaches a state where the flame runs around the ring like this.

I'm glad you explained what an excitable medium was. I was thinking Derek Acorah

YOU ARE A GENIUS! ❤❤ LOVE THE OPTIMIZATION PART

I love that this was stumbled upon naturally and you just when on a journal figuring it out. This opposed to looking through data of top searched for keywords and trends in areas where you want to make videos. This is just so organic and I love it!

All the best things start by experimenting with closed ecosystems!

Would love to see these dancing flames in total darkness! Great video once again!

You should do a grid of circles, or connected circles that are sized according to the travel speed of the flame front so there's a sort of "gear ratio" between the flame fronts (one ring goes around twice, one goes around four times). You could do SO MUCH with this concept. I love it. Edit: could also do a ring of rings. A mandala with carefully laid symmetry might do some cool stuff too.

Steve really just made a redstone clock with some flame vfx

That instantly reminded me of the cellular automata called wireworld (like its literally the same concept)! And you CAN make logic with it !!

This was such a fanscinating video and a wonderful presentation!

Fire computer was the first thing I thought of when I saw the and & or operations right in front of my eyes! I am going to start making gates this weekend. I wonder how consistent that flame speed is.

You should make interconnectable parts so that you can build custom track with logic: -straigth path -generator (the circle with one arm going out) -the splitter (Y shape) -gates that you can open/close along the path -...

Days after watching this, what most perplexes me is how you made the knowledge leap, from seeing this phenomenon to knowing the category of excitable media (I prefer that pluralization). If it was a category you already knew about, fair play--but if not, I don't know how I would start a research inquiry to even discover the category.

this actually so cool never seen this concept before

This is so cool! What a neat serendipitous discovery.

You knocked it out of the park with the very many relevant comparisons. It shows you dive in so deep to intrinsically understand the physics we all take for granted every day.

I love how you experimented with the ring parameters. Really shows how science can be done.

I am very *excited* for this!

<a href="#" class="seekto" data-time="605">10:05</a> I agree with the onscreen text. I think that as “media” gets used more and more commonly, the other plural “mediums” will become more and more distinguished in meaning from things like social media or news media. Which is interesting, because one might expect the more technical word to take the Latin/Greek plural and the more common word to take the regular plural, but the opposite seems to be happening here.

Pretty deep for what seems at first glance like a "toy" idea. Crazy to think about the relationship between geometry and energy and how one constraint the other into what seems almost like a living system.

Eternally burning forest cycle sounds like a strict idea for hell