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00:00You know what would be neat Steve if you could beam yourself up here for a weekend and we could
00:07just become the perpetual uber geek. About 10 years ago I was playing with some beads in my
00:16loft when I accidentally discovered this weird chain fountain phenomenon also known as the mold
00:22effect. No big deal. And unbelievably an astronaut just video called me from space so that we could
00:29figure out together whether this one little detail about my explanation of the chain fountain is
00:36correct because this one little detail can only be tested in zero g. And along the way we discovered
00:42that chain behaves a lot more weirdly than either of us had predicted. More on how all this came about
00:48later but first what is this thing that we were testing? Well my explanation of the chain fountain
00:53is generally considered to be correct following a six video argument with Mehdi from Electroboom.
01:00Hmm he was right. But one part of my explanation had to kind of just be accepted as true without really
01:07testing it because well it can't be tested properly in gravity. Now this might make me sound like a sole
01:13winner but I really just wanted to prove this last little bit experimentally. And anyway assuming it is
01:20right I just knew that it would look insanely cool in space. But what is this crucial part of the
01:26explanation that we're all just accepting? Well in the absence of gravity like on the ISS if you were
01:31to release some chain it should just float there in whatever random shape it was given. But what if you
01:38were to tug on one end of the chain? Would it flatten out? Or would it hold its shape and flow like this?
01:45We need it to hold its shape for my explanation of the chain fountain to be right. But why? Well look
01:52I can highly recommend a series of videos by me and Mehdi if you want the full explanation link in the
01:58card in the description for that. But in short the chain rises above the pot in a fountain because of
02:04an extra upward force coming from the pot. How strong does that force need to be though? Well it needs to
02:10be able to overcome the weight of this arc of chain that would obviously fall under gravity. And that's
02:17it. That's all you need. But you might look at this system and think well no the extra upward force from
02:23the pot needs to be much greater than that because look the chain is being yanked downwards by this large
02:29bit of chain down here. But that's the crazy thing according to the maths that yanking of the chain
02:35has no influence on the arc at all. If gravity wasn't a factor the arc would be fixed there in space
02:41even though it was being yanked downwards at one end. Or at least that's the theory. That's what we want
02:46to test. We want to test the theory that a chain moving at constant speed will flow through its own
02:52shape so long as it isn't acted on by an external force like gravity. What I really wanted to test was
02:58this. You've got a chain floating stationary in space and you tug on one end. Let's see what happens. But it
03:04turns out it's impossible to get a chain to be stationary in space. I actually think that setup
03:09wouldn't have been fruitful anyway because the behavior that we're looking for only works in
03:13steady state. Not while the chain is speeding up. And the whole chain would have had to speed up from
03:19zero movement in this setup anyway. A side note on how chaotic the movement of the chain is. Don likened
03:25it to the movement of molecules. We tend to model these like slowly moving blobs but there's a lot of
03:31energy down there. And just like in zero g there's nowhere for the energy to go. So the molecules sort
03:37of wiggle and writhe about just like the chain here. Anyway my other idea to test the theory was to hold
03:43the chain in something analogous to a pot. In other words just have it all bunched up somewhere and then
03:48pull one end of the chain out of that bunched up mess at a constant speed. And as you're pulling it
03:54if you give it a shape then it should hold that shape in space as it's leaving the pot. It should
04:02just add into what you've already created without that shape changing. The problem with that is it's
04:08basically impossible to pull something at a constant speed and the clumped up beads just get tangled and
04:13they start to float apart. And by the way we only had 25 minutes for the call because a satellite was
04:20going to go out of view. Actually a bit of a tangent about the tech behind the video call. I put some
04:26Skype sounds in at the start of this video because I thought it was funny but of course you can't use
04:31Skype to talk to someone in space because I mean you need to think about satellites and how are you
04:37going to communicate. It was Microsoft Teams. It was a Teams call. And like there was basically no lag.
04:43I don't understand how they did it. But anyway I had one more idea for how to test the theory.
04:48What if we turn the chain into a loop and then put the loop into a non-circular shape like a
04:55rectangle. My idea was to then grab the opposite sides of the rectangle and then like pull them
05:02like that. So that you're not throwing the chain anywhere you're just giving the chain motion like
05:09around the loop of chain. Intuitively you would expect it to pop out into a circle but if my theory is
05:16right then it should hold that rectangular shape. Third hand we're making a triangle and we're going
05:21to release it together. One, two, three. Three. Three. It's really... It's impossible. But obviously we
05:32couldn't actually get the chain to form that shape and hold that shape without anyone touching it
05:38because chain just doesn't do what you want it to do in zero gravity. On earth it's so easy to get
05:45something to stop moving. You just put it down. And when you took your hand away from the bead chain
05:51there was just so much energy in there already. It just kind of spreads out. But we just needed to
05:57get some non-circular shape and we needed to get the chain flowing. Yes. Hey look at that. It's almost a
06:04circle now. That's very cool isn't it? Yeah it is. Which is actually interestingly not what I expected
06:10because I was expecting it not to pop out into a circle. But look at that. It started... It's still
06:15rotating and I think the radial acceleration is going to straighten this thing out. Let's just keep it
06:22going. You've done stuff with like a drop of water and a bubble and things like that haven't you where
06:28it... You've got this... You've got this surface tension that's turning into a sphere or a circle. You don't have that here.
06:35So I don't think it ever will turn into a circle. That's the thing that is hopefully going to demonstrate this weird thing about chains.
06:42How cool is that though? It does seem to be holding its shape. Look even from this angle you can see part of the chain was actually bent out
06:51towards Don and that part of the chain shape is holding too. But Don has a point actually. The chain does seem to be very slowly turning into a circle or at least it's becoming more rounded.
07:04So does that mean I'm wrong? Well the mathematical analysis assumes that there is no friction between the joints of the chain and I had a suspicion that that might be why the real chain is slowly becoming circular.
07:17So I asked my friend Martin Bayer to simulate different scenarios for me. Here there's no friction between the joints. But look what happens when we turn friction on. Over time the chain becomes more and more circular.
07:30So I think it's fair to say that the chain is behaving how we would expect. Actually we discovered a few other really interesting things on the call.
07:38You are so right. This behaves totally different than a string because of the lack of friction at every joint and thread for sewing. It sticks out fairly straight. Its inherent stiffness shows up.
07:54But here with these low friction joints between every segment it's amazing what this thing does.
08:00It's so interesting isn't it how many things behave completely differently when you remove gravity. I had no idea that rope and string would just straighten out.
08:08Yeah.
08:09Because of the elasticity in it.
08:12Yeah.
08:13So you've got an intuition for how string and rope behaves on the ISS.
08:16Yeah.
08:17The chain doesn't behave like that.
08:18You see I could actually steer the string around by torquing on the yo-yo but a beaded chain has the mind of its own.
08:31It responds to air current.
08:33Yeah.
08:34It responds to gravity gradient. If you don't have air currents it'll end up stretching out in the direction of the gravity gradient if you leave it alone.
08:43No.
08:44It's really quite amazing. It doesn't work the way we thought it was going to work but then that's what it's like when you're doing a discovery.
08:53So this is around the world. And then this is the tether of cysts. So when you are in weightlessness you get to make up your own yo-yo trip names. And then let's see if I can make it company. There we go.
09:11Prior to the call Don was experimenting with static charge which meant we could loosely hold one end of the chain in place.
09:18Whoa.
09:19Whoa.
09:20See? It's...
09:23Oh that's crazy.
09:25Yeah.
09:26And I have video of this with a nice black background.
09:30circular way.
09:34Hold off again.
09:35Notice now with one free end it's really tough to control it, send a wave down.
09:46Each bead here is about three millimeters. I put a string of French clips together and these are 50 millimeter links.
09:57And I just want to show you that this behaves just like the beaded chain,
10:04but the leg scale is three millimeters to 50 millimeters.
10:10You might be wondering how all this came about, by the way.
10:12Well, after I made that video in my loft, I've been milking it ever since.
10:17In fact, you could argue that my entire career is built on a flailing chain of beads.
10:22Like, at one point I held the world record for the tallest chain fountain,
10:25but eventually it was taken by a TV show in China.
10:28Until I took it back.
10:30Three, two, one.
10:40What the hell happened there?
10:41And I guess at some point a three-story high sculpture was erected in Guatemala.
10:46And of course I got into a real public feud with that scoundrel electro-boom about it,
10:50and it was during that video argument that I mentioned the behavior that we've been looking for here.
10:55So in that video, I asked if anyone knows how to get the attention of someone
10:59on the International Space Station, let me know.
11:01Well, Stefan Ennis from the European Space Agency got in touch.
11:05Thanks, Stefan.
11:06And eventually, Samantha Cristoforetti climbed aboard a rocket with four meters of bead chain in her pocket.
11:12Unfortunately, she was quite busy, what with being the commander of that mission,
11:16so she didn't really have an awful lot of time to be fiddling about with beads.
11:21But she got the chain up there, and that's an important first step.
11:25And brilliantly, she put me in touch with another astronaut, Don Pettit.
11:29Now, the great thing about Don is you can nerd snipe him.
11:31Oh, look at that. Look at that.
11:35I mean, there's a lot of great things about Don.
11:37But anyway, I explained about the bead chain currently languishing on the International Space Station,
11:43and he really got into it, and he said he'd look for the beads next time he was up there.
11:47And then at some point we were emailing about the experiments, and he said,
11:53you know, look, it's hard to really communicate over email.
11:56Let's have a video call.
11:58And I was like, yes, that would be amazing.
12:01Just like on a personal note, this was obviously a once in a lifetime experience.
12:08Just unbelievable.
12:10There was a period as a kid where I wanted to be an astronaut,
12:13but the job that I ended up having, which is making science videos on YouTube,
12:19somehow means that I ended up having a video call with one.
12:23And like we were doing science together, science that had never been done before.
12:31You know, it just, I almost can't believe it happened, but yeah, beads in space.
12:37I think I peaked. Literally.
12:41A huge thank you to Isa and Samantha and Don and NASA for making it happen.
12:50An extra big thank you to John Stevens, the person on the ground at NASA who put the video call together,
12:56made sure that all worked.
12:57Because honestly, like I was pretty nervous about it because we only had one shot.
13:02It was 25 minutes and my internet at home was terrible.
13:06So I had to, you know, set up somewhere else that had good internet.
13:10And John just made it all really smooth.
13:13Put my mind at ease.
13:14The full conversation, unedited, plus Don's extra footage that he filmed for me outside of the video call,
13:24unedited, is available over on my Patreon.
13:27Link in the description for that.
13:29Oh, also thank you to Rohan Francis from Medlife Crisis, because he was all over this.
13:35Even before I got in touch with Isa.
13:37Look at him go.
13:39So there you go, that's the evidence that we have from space.
13:44What do you think?
13:45Does it prove that a chain will flow through a fixed shape in the absence of gravity?
13:51Does it change your opinion of my explanation of the chain fountain?
13:55It was a great demonstration, seeing it pass through the same path through the loop,
13:59and your explanation about why it would eventually turn into a full circle due to friction was pretty adequate.
14:05So I guess I agree with everything you said in your video and don't have to embarrass myself making another debunk video.
14:11Although you didn't quite demonstrate if the path will remain the same if the chain wasn't in a loop.
14:18Another simulation might be nice, but what would be better is to take 100 meters of chain into space and drag it behind you in a spacewalk.
14:28Do it!
14:28We just got the rug pulled out from under us, Steve.
14:31It's just been so interesting, so interesting to see it.
14:35Yeah, it is, and it has been really good actually talking to you so I could understand, you know, what we want to look for.
14:45It looks like we're just going to walk off the end of our KU band and then I'm going to have to vacate because...
14:55I think that's it.
14:55I think that's it.
14:58Okay.
15:00Wow.
15:01Ugh!
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