Dr Ben Miles - 2024-06-16
Why is Ice Slippery? New research suggests we finally have an answer. Source article: https://www.nature.com/articles/s41586-024-07427-8 0:00 Why is Ice Slippery? 1:14 The History of Understanding Ice 2:15 The Pressure Hypothesis 5:41 The Quasi-Liquid Layer Theory 6:50 The Results 10:17 Cold Ice Isn't Slippery 🚀 JOIN US for members-only content: https://www.patreon.com/DrBenMiles 🤘👨🔬 ROCKSTAR SCIENTIST Merch: https://www.rockstarscientist.org/ 📸 INSTAGRAM https://www.instagram.com/drbenmiles If you enjoy the channel and want even more physics, tech, and business content, I've just launched new Instagram and Threads pages. Follow on the links below Insta: https://www.instagram.com/drbenmiles Threads: https://threads.net/drbenmiles Newsletter https://drbenmiles.substack.com/ A few people have asked so I've added the info below. Some of these are affiliate links. If you make a purchase it doesn't cost you anything extra, but a percentage of the sale will help support this channel and my work to bringing entrepreneurship into science. My camera : https://amzn.to/3ed5Xac My lens: https://amzn.to/3xIAZyA My lav: https://amzn.to/2SeE20Y and https://amzn.to/3nK33wA My mic: https://amzn.to/3gUYYEv
This was fantastic and I remember all the old videos that basically said 'this is our best guess but it doesn't actually make sense' so this was really satisfying
As someone who lives "quite far north" I can attest to the fact that ice gets less slippery when it's REALLY cold. Bur also if the soles in your shoes are cheap and contain more plastic than rubber they get hard as bakelite and insanely slippery.
Also if it's really cold and there's a slight layer of powder snow on perfectly blank ice you're screwed. There's no more slippery surface in the world. Literally no friction. It's like being the puck on an air hockey table 😅
I believe you. But coming close is a hard rock road (graded flat and smooth) with clay over the top (also graded smooth) and rain. That's extremely slippery as well.
I live quite far south. It's always so hot.
@@Myron90you live not as much far South. Really far South is also cold
@@Myron90 you live quite far middle, then
I can't hear the word bakelite without having flashbacks to End of Evangelion.
Brilliant video. My favourite of yours so far (as a fellow PhD physicist, I really appreciate how much work you've put into researching this and loving the cheeky humour too. This new explanation of a classic phenomenon that we thought we understood reminded me of a fairly recent result showing that static electricity (e.g. amber and fur) isn't due to electrons as we thought, but molecular ions. Apparently, a chemist proved the electron model was energetically impossible. A bit embarrassing for us physicists, but I bet he was a physical chemist, so we can take the win anyway
😂). Keep up the great work, Dr. Ben!
I had a Chemistry Teacher demonstrate a Solid - Solid Chemical Reaction.
It was quite odd looking. Two different white powders were placed in a glass tube.
The tube is shaken only one toss at a time. In the tube blue crystals quickly formed.
The crystals grew each toss of the tube but not otherwise. There had to be mechanical motion and contact.
Won't you remember which solids were those? Looks like an amazing experiment
But seriously, if you recall the chemicals involved I'd love to know, might duplicate the demonstration.
i would like to add to/reinforce the inquiries about which solids they were!
With the utmost reverence, I, being the fourth person to inquire, humbly beseech you to graciously reveal the esteemed identities of the two venerable white powders that were utilized in this noble undertaking, so that I might fully grasp the intricate details of their application and import.
I, too, wish to humbly add my name to the list of others requesting this knowledge of you. I seek their import and subsequent application for the entertainment of my 4 year old niece. Even if she isn't entertained, I will be.
EDIT: My research indicates it might be some form of Copper Sulfate.
The background baseline of "under pressure" and "ice ice baby" is just sublime when talking about vacuum @2:20.
actual timestamp: 2:13 (dont put your timestamp at the end of the section you want to talk about)
@@shyguy1597 39 buried, 0 found
i hate the fact it cut off when it was about to be crushed
And friction by imagine dragons at 5:40
do you know why, when you wet your fingers with a tiiiny amount of water you get insanely good grip (on a smooth metal surface for example)? completely dry fingers are slippery and completely wet ones too but theres that perfect amount of water that gives you an insane amount of friction
The answer is probably capillary forces pressing your hand and a surface together.
Just lay 2 flat glass sheets on top of each other and add 1 drop of water between them - You'll be surprised how much force is required to pull them apart
this is also the case with some types of garbage bags. With dry fingers its hard to seperate / open them but with damp, not wet, it's easy
@@cyfralcoot65 Yes, capillary forces contribute to improved "grip". A much bigger contribution though comes probably from the increase in contact area. Imagine two sheets of any solid material put on top of each other. The force required to separate them decreases with increasing surface roughness, i.e. decreasing contact area. In other words, the sum of attractive interaction forces between these two surfaces in contact depends strongly on the number of atoms (per unit area) at very close distance across the "gap". Now, instead of polishing two rough surfaces you get a similar effect here by adding water to "smooth out" the roughness, i.e. increase the "contact area". An indication that the contribution of capillary forces is not as big may be derived from the fact that compared to wet fingers you get a similar effect of improved grip with "greasy" fingers. Grease or fat are semi-solid materials, so capillary forces are not existent or negligible in that case. Of course, this is still not the whole picture but hopefully a useful illustration.
Just a hypothesis, but it might have to do something with the oiliness of your fingers. By applying water, the oils on your fingers are rendered less effective. I wouldn't be surprised if there is an optimal point between reducing the effectiveness of the oil and the effect of the liquid water itself. But like I said, that's just a hypothesis.
That's because of the grease on your skin. Clean the properly and this happens way less
I started watching this video with the thought "I will probably not understand this". But you explained everything very well. Good job and thank you!
Therapist: "double-bonded hydrogen isn't real, it can't hurt you"
Double-bonded hydrogen: 6:25 (right side)
what is that abomination
Don't kink-shame, just a different kind of bondage bonding
Hydrogen bonding:
erm what the sigma?
lmaoooooo I see it now lmaoo
3:17 Thank you for voicing something everyone who's studied engineering has felt.
Was looking for this comment 😂
This is a perfect illustration of the problem with active measurement. The energy introduced to the system to measure it changes it. Therefore what you are measuring is the system plus the measuring method. So you can never measure just the system.
Are you making a reference to the QED measurement problem in your statement?
Yes. That sort of question was always in my mind when reading/reviewing AFM-type experiments (I was working with surface plasmon resonance at the time).
Also, more than one supervisor reminded that "remember, this is their best data they are publishing". Asking how often another pattern was observed tended to make people get a bit scientifically defensive.
I'm not weird >: (
Who the hell let you out of the sub-zero control freezer?
It’s okay. I don’t think you are
@@Wolfentodd they said i was too "cool" for that place
@@coldicecubes0 did they write an-tartic-le about it?
Careful your melting away 🥴
Lol, the bloopers at the end were priceless. Here you are trying to prove something mundane that we all know happens and the ice gods just aren't letting you have it.
Not proving, explaining
Sounds like most of my experience chemistry labs. I'm sure bronze age people were better practical chemists than me.
The subtle change from Ice Ice Baby to Under Pressure at 2:13 is genius
So the AFM is actually like a really small record player stylus.
And with the laser bouncing off there are 2 levers involved:
The stylus is one and the laser beam is the other.
With a rather odd definition of lever, sure.
Paint It Black (ha ha) and the beam will apply 'pressure'. Hey... I know! Apply a Vanta black surface treatment. Oh crap, then you will not be able to see the laser bounce! I suddenly hear David Bowie music in my head... I am getting old.
@@cosmicraysshotsintothelight The beam will exert more pressure (twice as much to be exact) if you make it nice and shiny rather than black.
The explanation in the video is oversimplified, but sure. The actual paper used non-contact mode AFM, meaning the tip oscillated just above the surface and the atomic force was derived by modulation of the amplitude or frequency of the oscillation
The world's smallest phonograph player. LOL
2:44: That has to be the most clarifying picture of water freezing to ice that I've seen. It's so beautiful, you immediately see what happens and why.
4:15. I don't know that I buy the idea that there are three square inches of ice skate on the ice when a person is in motion. (The area required for a 150lb person to be exerting 50psi.) I suspect the real expressed area is quite a bit less than that.
How wide is the blade of a skate used by figure skaters? 0.4 centimeters? It is curved, so less than the full length is in contact with the ice; say 5 or 10 centimeters. Based on these assumptions, the contact area could be around 2 to 4 square centimeters. That is a factor 5 to 10 less than 3 square inches. So I agree with you.
@@Bob94390 To bottom of an ice skating blade is not flat but concaved so the width that touches the ice is much much less then the blade's width, it's actually 2 very thin blades that you skate on called the "inner edge" and "outer edge".
I agree, but I gave up after googling for lengths and widths of hockey blades and receiving exclusively articles about blade radius, which is apparently a keyword.
I say, take the blade length and multiply by the width of a cunt hair times two.
@@elirane85 It is all touching. Those "edges" are what are there and are "sharp" (concave face) to allow the skater to use his down force and that cutting edge and the skate blade tilt angle and skate blade lengthwise arc to effect a turn or vector alteration. The racing skates have a flat squared face on the edge, which is one reason why they step through turns on their tracks and use big long body weight shifts and not a convex curved edge kick to accelerate against. Even in the case of the concave faced blades the entire blade face 'touches' when 'gliding'. Like the difference between 'riding ' a skate board and the leg kicks to get it going and keep it going.
The third skate profile is found on ice yacht blades. These are sharpened to knife edges with about 90 degrees angle. The blade must be slightly curved for best performance with a short flat centre section. It's noteworthy that in practice speed skates have a similar 90 degrees effective angle on the edge that touches ice. Based on personal experience, smooth ice is slipper than rough ice. For safe walking on smooth ice the worst conditions occur when there is a thin layer of dry snow covering the ice. It's like walking on roller bearings.
Real interesting stuff! Double points as this made me unlearn something I thought I knew. And it as this generates a bunch of follow--up questions too!
Can't access the paper right now but I'll definitely give it a read at some point.
I knew about electron tunneling microscopes, this looks a slight bit simpler than that. The fact that we can scan atomic-scale resolution is mindblowingly fantastic.
If you are in an AFM Lab and the people there are in a mood to do it, ask them to scan graphene with one. It can manage to produce incredible pictures where you can clearly see the graphene structure (iirc we managed do get a frame of 3 by 3 nm). Also AFMs can be used to probe for magnetic fields (for example it's possible to visualize the data written on the disks of old harddrives) or you can graft polimerized surfaces and do very fine engravings.
atomic-scale AFM is fairly difficult, by which I mean you need the proper setup. Like all atomic-resolution methods right now, it mostly only works at cryogenic temperatures in vacuum... but more generally easy-to-use AFMs can still get nanometer order resolutions and can be modified to measure all kinds of other phenomena (conductivity, work function, magnetic moment, piezoelectric effect, etc.). Liquid environment AFMs also operate at slightly lower resolutions and can pick up electrochemical signals and the like. My second most cited publication (sadly not first author) was used electrochemical microscopy to detect analyte activation on sensing nanoparticles.
@@admthrawnuru Why does it have to be so cold? Is it because at higher temperatures the atoms move around too much?
I know a reasearch group who just uses a platinum wire which they cut off at an angle with scissors and then pulse current through a few times till they have a one atom tip. Works quite well for their use case and was quick
@@Hiandbye95 (I can only tell from own experience.) With graphene we didn't need a vacuum or cryogenic temperatures. Essentially the tip of the cantilever was send rapidly across a small area of the graphene. This does produce pictures of the graphene structure, but they aren't the smoothest. Essentially the scan lines would be slightly off the nexts position. I assume it's possible to do much better under cryogenic temperatures in a vacuum and it may be needed for materials other than graphene (seems pretty plausible to me).
slippy 🥺12:31
🥺👉👈
Awesome video! The interesting thing is that the "it melts slightly under pressure" explanation was parroted as fact for so long. There's an old Feynman video (1986-ish) where he gives that explanation.
What I find weird is how so many people refuse to read my comment and refuse to understand anything I wrote.
Just don't read this if you're feebleminded, people.
What I find weird is how it managed to get parroted that much, because the notion that it melts a fine layer on top under pressure is still just a circular argument. You end up with a layer of water but why is *that* slippery? They --> (the people in the past, aka ---> BEFORE <-- this video, so teachers from the 80's and 90's, so not this video.) couldn't explain it other than saying "the water is slippery, not the ice", which is slightly true but in fact it's the individual molecules that have no fixed lattice to adhere to. Even Feynman fell for it, which makes me feel quite a bit better about myself when my teacher (elementary school 4th grade) gave the same explanation and I kept saying it was a circular argument because it's not explained why the water is then slippery.
It is NOW explained by the video, the marble analogy didn't exist back then, so it was circular reasoning.
@@Yezpahrwater…is slippery tho. It’s not a circular argument to say water is slippery. Everyone knows that a thin sheet of water acts as a lubricant and is slippery, hence “wet floor” signs and hydroplaning. You really weren’t as clever as you thought you were and this seems more like a r/im14andthisisdeep type brag.
@@YezpahrI've never in my life heard a 4th grader say "circular argument" or even have the wherewithall to properly follow an argument in a way that could allow them to state that. With that being said, I'm calling cap on you homie.
@@1dfr33 In my country we actually got education, instead of 4 years of kindergarten.
@@ClementinesmWTF Your reddit lingo is meaningless here. They didn't explain water was slippery, they just said it was.
I do occasionally grab a drop from the faucet to gain *friction* on the garbagebags when getting it off the roll and to open a new bag... so it is slippery you say, but there are more forces at work as to *why the ice* is slippery in the first place which nobody explained until these papers came out.
3:14 "Thompson was one of the inspirations in the field of Thermodynamics, something I'll never personally forgive him for"
Me too, me too...
The "I" in ice Ih and Ic is the Roman numeral one. It should be pronounced "ice one h" and "ice one c". Fantastic video! Great work!
Yet another example of font failure
Ith
Icth
Ith bronounthd li yuh tug ith frothed sthoo a flagpole
@@scott98390 there is no font that will show you the difference between a roman numeral one and an I
@@killerbee.13 U+2160
edit: Ⅰ
@@killerbee.13 technically there is a separate Unicode character for the roman numeral "Ⅰ" that isn't the same as the latin alphabet capital I, but because people pretty much always just use the latin alphabet I for both and most fonts don't have the roman numeral version so it doesn't really matter
this was a great video, excellently explaining this newfound knowledge in a great format without wasting time. I also appreciate the subtle, unobtrusive bits of dry humour throughout.
This is just a meme compilation of people slipping on ice. You cant change my mind
They know what they were doing.
With a bit of science and history sprinkled in there for a bit of flavor
So are the comments... and they are crystalizing and accumulating... Snow flakes and Ice cubes and glaciers, oh my! No wonder they carved out lakes. The slippery side is 'up top'!
his editor is low-key awesome
well thas some cold hard slippery news..
0:00 solid ice bonding together is actually a rather common thing to occur for solids near their melting temperature. It is called sintering. We rely on this phenomenon to form solid high temperature materials, such as technical ceramics and high temp metals.
Two ice cubes fresh from the kitchen at -8 degrees C act more like proper solids and don't stick together when pressed. Interestingly, they also sound different when knocking against each other.
However, they are still slippery, and if I drop one it will shoot off along the floor. Also note that in winter sports, a colder ice rink is "faster" for skating.
He mentions and explains this in the video.
The colder they are, the more like proper solids they act.
I notice in the out-takes that you had trouble getting it to stick together, too. I'll bet they were fresh from the freezer; too cold for that trick.
It works when the ice is at equilibrium, actually melting to maintain the freezing-point temperature of the rest of it.
You all should google "gauge block wringing" to see that "proper solids" stick to each other easily but must be very very very flat.
@@xqr2911waters just taking up the air space and causing suction cupping
And this explains an observation I made ever since I was younger. Fresh snow is filled with crystals, but the older it is, the more it turns into balls of ice. And it doesn't seem like it even needs to melt first for this to happen. It's as if it's transforming from a crystal shape to a ball of ice shape over time. This quasi-solid layer could explain that.
Like soap bubbles ...
Wow, it's not often that I get to see such a big common mystery definitively solved! Major kudos to the researchers and to you for breaking it down so clearly
as a bartender with a lot of free time, if you actually press the cubes with enough strength they stick together instantly. I believe it's because you give enough energy to the mollecules that are unsure about their orientation to move and when you remove the pressure they return to solid.
Skate blades are not in the shape of a point like a typical knife but are in a concave curved C. This way each side has its own edge to grip into the ice better for turns etc.
Icehockey and figureskating blades are. Speedskating blades are flat with 2 90 degree angles.
I don't know why YT finally got around to suggesting your channel, but for once the algorithm was SPOT ON! Loved this video, and with your sense of humor I'm convinced that we are somehow related. XD
Subscribed. Keep up the great work!
It is my understanding that wooden-shoes ( yes I'm Dutch ) are anti-slippery, the question ( if true ) is then why?
The fridge workers in old capetown used clogs
Wood fibers absorb the water and freeze, kinda micro gluing you to the floor. It's really an amazing process, and not only that, it's completely made up.
Do you walk on clogs regularly? Because I can tell you that's not the case.
@@aukir Stand in one place on a cold enough day on ice and with cold enough clogs and they will "seize in place". Maybe some of the superglue you were playing with got onto your eyelids. It is really an amazing process.
I never walked on ice with them, but almost always experience snow sticking to their soles an building into a sort of snowball unterneath that walk very awkward, until it breaks of after getting 5-10 cm thick. This is at temperatures when the snow is sticky as you experience in the Netherlands.
An excellent vid. I recall a winter storm years ago. A freezing rain left a layer on asphalt that was "super slippery. Walking across one road I slipped at least four times.
Metals will also fuse if they have a surface of sufficient flatness and they do not have an oxide layer. Infact, most metallic machine parts that require fasteners like screws or bolts will use different metals to prevent a weld forming when the faster is tightened.
Veritasium’s been real quiet since this vid dropped
He can just make a video explaining why he was wrong. That's how science works lol
@@UrduhkhanScience, that's on the internet. So he needs to double down. That's how the internet works.
> Physics grads: why is ice slippery > CS grads: how can I make sand think
😂😂
How do i make sand do my earthly bidding
OK... now try that with the grains of dust in a bag of flour.
Or crabs. They started to make crabs think, once, that was fun. Crabs computer.
@@colbyboucher6391 Coconut crabs! New drone 'firmware'.
video starts at 9:04
From what i have personally noticed below -34C i can't find anymore slippery ice.
Very cool experiment, cheers. 🙂
That could be due to how your shoe behaves at that temp. There are probably other factors you'd need to keep in mind.
@@vez3834 Not just on my shoe, it's hard to explain but by touch with any object, metal flesh, rubber, fur doesn't matter you can feel in how it slips one feels like cheap chalk on a chalk board and when it's warmer it slides.
What I personally noticed is below -34C I can't find anymore water
I like explanations that dig deep enough to actually explain something on a molecular level. Nice!
AFM probes are rarely metal, usually made of silicon or silicon nitride. Metal probes have lower resolution and higher wear, so they're often metal-coated instead. 7:30
Is silicon not metal?
@@unclejimmy7metalloid no?
@@unclejimmy7 It's a metalloid.
@@ratdoto2148 They should use some of the crystal they grew to make the new kilogram standard. Now that is some clean crystal (probe) candidate material. I think the tips are grown not machined though, right? So... oh well.
@@cosmicraysshotsintothelight What? The Kilogram is now based on a fundamental value, it never changes. Why would you change it back to some physical nonsense?
"It's complicated" then proceeds to describe a rolling conveyer line
What a fantastic science video! For the first time in my life, I feel like I’ve heard a genuinely plausible explanation for why ice is slippery!
Thank you!
That trick with using the reflected laser light to detect tiny oscillations is so clever.
The blocks of ice fuse when pressed together in air that is above their melting point, because their surface first melts then resolidifies. Try doing that in air below the melting point and at the least enough pressure would be needed to correspond to a pressure weld.
You can definitely do that without melting or much pressure with other solids - like metal in room temperature. The surface just needs to be extremely flat - look for "gauge block wringing".
This is easily replicated by taking two ice cubes from the freezer and trying to stick them together.
If you wait a bit until the outside is just warm enough to start melting you can stick them together and the heat being absorbed by the two cubes will solidify the water layer.
Absolutely marvelous video. A problem that often comes up in the sciences is that once we have a model that seems to explain a phenomenon, the model becomes the reality, in the sense that it outweighs taking a fresh look at the actual phenomenon. For example, when I studied material science, electrical and thermal conductivity in metals was explained by electron mobility. But that didn't explain how electrical and thermal conductivity vary, metal to metal, in an uneven manner. And then you find that diamond conducts heat several times better than silver does, while diamond is the best electrical insulator and silver is the best electrical conductor. This explanation of why and how ice is slippery is so beautifully subtle!
One of those topics that turned out to be much more interesting than you would imagine! Learning that certain ice-based sports have temperature preferences was a real "Really?" moment :)
I'm blown away by the simple explanation of the measuring device. Thanks!
icy what you mean
IC it 2
Icy what you both did, there!
@@poldidak They're pretty cool!
You can c yourself out
@@rogerneedham8775 😂
Apparently they used "qPlus-based cryogenic AFM with CO functionalized tip"! Wow, wow... wow. I love learning about the advances in measuring equipment.
@michaeldaniels3865 - 2024-06-16
It makes me wonder if these observations could inspire a "slippery" metal alloy that never needs lubrication
@orchdork775 - 2024-06-16
Interesting!
@fireworkstarter - 2024-06-16
youd need a metal alloy that wont ever rust since that would not make it pack propperly into a crystal again and it needs to be able to turn liquid again under pressure
@dtibor5903 - 2024-06-16
Yes, that metal is bronze... Although it needs some lubrication for best performance. You find bronze bushings in small motors and fans.
@pon1 - 2024-06-16
PLEASE someone invent that!
@SeekingTheLoveThatGodMeans7648 - 2024-06-16
Any alloy would be slippery at its melting point. A bearing filled with a liquid like mercury (or safer, galinstan) -- as long as it could be made so that it would not leak its liquid and its temperature never reached the freezing point of the liquid -- might be a possibility.