[0:00] Have you brushed your teeth?
[0:01] >> Yes.
[0:02] >> H Let me see. I made a video about Gel
[0:06] Site about 2 years ago, and they just
[0:07] released this new one that goes even
[0:09] smaller. Its purpose is to take precise
[0:12] 3D measurements of very small things.
[0:15] But here's what I've been using it for.
[0:16] I've been comparing fake things to real
[0:18] things, old things to new things, and
[0:21] natural structures to synthetic
[0:23] structures. We discovered loads of
[0:24] amazing things, and I'm just going to
[0:26] show you all of them. Like this, for
[0:28] example, is the grippy surface on a
[0:30] PlayStation 5 controller. How cool is
[0:32] that? There's a link to the original
[0:34] video in the description, but here's a
[0:35] quick recap of how the thing works. So,
[0:38] what shape do you think a poppy seed is?
[0:41] Under a normal microscope, it's hard to
[0:42] tell because the surface of a poppy seed
[0:44] is black, but you'd probably assume it
[0:46] was roughly spherical. But if you could
[0:48] spray paint it like 50% matte gray, it
[0:52] would be a lot easier to figure out the
[0:54] shape of the thing. And that's the idea
[0:56] behind this weird microscope. It's as if
[0:58] it gives your subject a temporary coat
[1:01] of extremely neutral paint. And look,
[1:04] when an object is the same color all
[1:05] over and you shine a light on it from
[1:07] one direction, your brain can easily
[1:09] figure out the shape based on which bits
[1:12] are dark and which bits are light. This
[1:14] object is the same shape, but it's much
[1:16] harder to get a sense of its dimensions.
[1:18] But how does the Gelite microscope
[1:20] achieve this temporary coat of paint?
[1:22] Well, the camera is behind a gel pad,
[1:25] which confusingly is red, but the camera
[1:27] is black and white, so it comes out
[1:29] looking gray. Here's a large model of
[1:31] it, so I can show you what I mean. If I
[1:33] press my finger in on this side, you can
[1:36] see a gray version of my finger on this
[1:39] side, and that's what the camera sees.
[1:41] And there's lights on the inside, so it
[1:44] can be lit from different angles. And
[1:46] so, you can really get the sense of the
[1:48] structure of a poppy seed, for example.
[1:50] And isn't that amazing? I had no idea
[1:52] poppy seeds were shaped like that. It's
[1:54] kind of alien looking. So this way your
[1:56] eyes can more easily discern the
[1:58] structure of things. But interestingly,
[2:00] the software can actually map out in
[2:02] precise detail the 3D structure of
[2:05] whatever you press into the gel. More on
[2:07] that later. Gel site aren't paying me or
[2:09] anything, by the way. I just wanted to
[2:11] make a video about it and they said I
[2:13] could borrow one for a couple of months.
[2:15] Right, let's have a look at some stuff.
[2:16] This was the real versus fake example I
[2:19] showed you earlier. I don't know if you
[2:20] had any guesses, but this is real frost.
[2:23] And this is frost from a spray can.
[2:26] Frost is amazing. Actually, you can see
[2:28] the six-fold symmetry that arises from
[2:30] the underlying crystal arrangement of
[2:33] the water molecules. It's the same
[2:35] reason snowflakes have six-fold
[2:37] symmetry, but it's surprising to see
[2:39] those little turret looking things here
[2:41] and there. My car gets this spidery
[2:43] looking frost sometimes. That's pretty
[2:45] cool. And this is how the frost on
[2:48] blades of grass look. Actually, crystals
[2:51] in general are really fun. This is salt
[2:53] flakes. The symmetry is different
[2:55] because the underlying crystal structure
[2:57] is different. So, you end up with right
[2:59] angles and squares and cubes instead of
[3:01] hexagons. For comparison, here's fine
[3:04] pouring salt. You can still see lots of
[3:06] right angles. I guess they're all little
[3:08] cubes. I was a bit worried about pushing
[3:10] something so pointy into the gel, but
[3:12] actually it seems to fite well. This is
[3:14] the needle from a record player, for
[3:16] example. And this is what happens when
[3:18] we smeared tuna paste on it. If you're
[3:21] like me and you try to avoid thinking
[3:23] about the fact that cat tongues are
[3:25] spiky, well, I I'm sorry I reminded you,
[3:28] but anyway, this is another spike that I
[3:30] always wanted to take a proper look at.
[3:31] You find these on the back of a leaf.
[3:34] You can hardly see it with the naked
[3:35] eye, but it has the effect of only being
[3:38] able to stroke the leaf in one
[3:40] direction. If you've ever experienced a
[3:42] one-way leaf, this is why it's like
[3:45] that. This is what it looks like to
[3:47] write on gel site with a ballpoint pen.
[3:49] You can see the ball rolling around. I
[3:52] guess this is what it feels like to be
[3:53] paper. And for comparison, here's a
[3:55] pencil tip. You can see where the
[3:57] sharpener stopped sharpening. Coral is
[4:00] surprisingly sharp. Like from a
[4:02] distance, it looks like a smooth surface
[4:04] with little holes in it, but it feels
[4:06] really rough. And you can see why under
[4:08] a microscope. It's basically a load of
[4:10] tightly packed spikes. This is another
[4:12] type of coral and you can see all the
[4:14] tiny tubes. How cool is that? I like
[4:17] this one so much I printed it out. But
[4:19] how was the software able to extract 3D
[4:21] information from this image? Well,
[4:23] because that gray color is so even,
[4:27] there's a direct correlation between the
[4:29] brightness of a pixel and the steepness
[4:32] of the slope in that location. But
[4:34] because the direction of the slope also
[4:36] affects brightness, the software needs
[4:38] to take multiple pictures that are lit
[4:40] from different angles. The 3D
[4:42] information can then be exported in a 3D
[4:44] format, which means you can zoom in even
[4:47] more.
[4:49] Wait,
[4:51] wait.
[4:53] Nature has layer lines. You might have
[4:55] spotted some interesting structures in
[4:57] the background of the spiky leaf. And
[4:59] actually, leaves are really interesting.
[5:02] You can see this sort of branching even
[5:03] at a really small scale. They kind of
[5:05] look like veins. Some leaves don't have
[5:08] a fractal structure because they're
[5:09] actually feathers. Fake feathers look
[5:12] nothing like real feathers, by the way.
[5:13] Not that you need a microscope to
[5:14] discern that. But on the subject of fake
[5:16] and real things, which one of these do
[5:18] you think is real leather, and which is
[5:21] pleather? Well, this is the real
[5:22] leather. You can see those little pits,
[5:25] which I believe is where the fur was
[5:27] plucked from the hide. I've not found
[5:29] any fake leather that tries to replicate
[5:31] that detail, but it's not always that
[5:33] easy to tell the difference between
[5:35] natural and synthetic fibers. Can you
[5:37] tell, for example, which is real hair
[5:39] and which is plastic hair from a wig?
[5:43] This is some wooden furniture and this
[5:46] is fake wood veneer. The difference is
[5:48] quite clear. The veneer is perfectly
[5:50] flat except for the grooves, whereas the
[5:53] real wood has a general roughness to it
[5:56] as well. This is a nylon rope and a
[5:59] cotton rope. The nylon's much smoother.
[6:02] This is horsehair, which is to say it's
[6:04] a cello bow. The gel pads don't like
[6:07] being scraped, but I wanted to see what
[6:09] it would look like to drag the cello bow
[6:11] across it. So, I added a bit of
[6:13] lubricant. That's cool, isn't it? While
[6:16] we've got lube on the thing, here's
[6:17] Lycra or spandex being stretched.
[6:21] And here's Velcro. You can see the hook
[6:23] and loop in action there. And you can
[6:26] see where the hook eventually gives way.
[6:28] Let's have a look at some more synthetic
[6:30] objects. This is a printed circuit
[6:32] board.
[6:34] This is a light bulb filament. You can
[6:36] see that the coiled up wire is itself
[6:39] made of a coiled up wire. This is a
[6:41] pill. This one helps me make videos.
[6:43] Actually, it's got a clever design that
[6:45] lets you split the pill in half and then
[6:47] in half again.
[6:49] Woven fabrics look really cool,
[6:51] especially netting type fabrics like
[6:53] this laundry bag. You can see how all
[6:55] the different strands are all kind of
[6:57] hooked together. Here's some woven
[7:00] metal. And here's a tea strainer.
[7:03] This is sound waves carved into a disc.
[7:06] Not sure what that's about. I'm a big
[7:07] fan of nurling actually. And it looks
[7:10] really nice up close. These are some of
[7:12] my favorite knurled objects. Look at
[7:14] this though. It's like nature's nurling.
[7:17] Looks very different up close though.
[7:19] Let's have a look at some more natural
[7:20] structures. Actually, this is fish
[7:22] scales. I didn't take this one. Mrs.
[7:24] Jessica Arbor specifically, it's an
[7:26] orange throat dart. And the spikes on
[7:29] the edges of the scales actually helps
[7:31] to reduce drag. This is a pepperc corn.
[7:35] And this is some fungus. These are some
[7:38] more interesting seed varieties, though
[7:42] poppy seeds are the best in my opinion.
[7:44] I just want to go on a poppy seed
[7:45] tangent for a second because they're so
[7:47] cool. There's very often two different
[7:48] ways to explain why something is the way
[7:51] it is in biology. There's the mechanical
[7:54] reason and the evolutionary reason. The
[7:57] mechanical reason is that as the seed
[7:59] forms, the outer layer of cells fit
[8:02] together like hexagons and pentagons.
[8:04] The joining walls of the cells are
[8:06] thick, but the top walls are quite thin.
[8:08] So, when the poppy seed dries out, those
[8:11] top walls collapse, and you're just left
[8:13] with those joining walls. But what
[8:16] evolutionary pressures push the poppy
[8:18] seed towards that shape? Well, it's
[8:20] probably a few things. Seeds need
[8:23] protection, but in the case of poppy
[8:25] seeds that are dispersed by the wind,
[8:27] they also need to be really light. So
[8:29] instead of a full heavy outer shell,
[8:32] it's protected by lightweight ridges
[8:34] instead. And a bit like the dimples on a
[8:36] golf ball, the rough surface might help
[8:38] the seeds to be carried further by the
[8:40] wind. And finally, when the seed does
[8:43] land, that pitted surface helps to
[8:46] retain moisture. This is owl poop. Check
[8:49] out what's inside, though. Well, lots of
[8:51] fur for a start, but this is probably a
[8:54] mouse jaw. And there's a bit of spine
[8:56] there and some tail.
[8:59] I bought some dead bees on eBay because
[9:01] I wanted to see the compound eye. That
[9:03] doesn't really show up, unfortunately.
[9:05] But it's interesting to see a gray bee
[9:08] slowly being crushed. And here's a dead
[9:10] spider.
[9:12] These shots kind of remind me of horror
[9:15] movie posters, you know what I mean?
[9:16] It's often like something being pressed
[9:18] into fabric. I don't know why, but
[9:20] anyway, here's a tiny skull that I
[9:22] found.
[9:25] I suppose I should try and use this
[9:26] thing for what it was designed to do.
[9:28] And actually, in my video about bone
[9:30] drills, I cut a groove in the nail of my
[9:33] thumb. There's a nice feature where you
[9:35] can remove the first order slope, so you
[9:37] don't have to worry about getting the
[9:38] angle right when you press it into the
[9:40] gel. And so now, look, when I analyze
[9:42] the depth of the groove, I can see that
[9:44] it's about 300 microns or about.3 mm.
[9:48] The nail itself is only about.5 mm
[9:51] thick. So, a couple more takes and I'd
[9:53] have started to be in trouble. I made a
[9:55] video about atomic trampolines a while
[9:57] back. The reason the amorphous metal is
[9:59] so bouncy is because it doesn't
[10:01] plastically deform on impact. Compare
[10:04] that to steel where impacts create these
[10:07] little divots. You can exaggerate
[10:09] defects in the software to make them
[10:11] easier to see. And look, measuring it,
[10:13] it's only 16 microns deep. And actually,
[10:16] it's interesting in general to look at
[10:19] old things versus new things under the
[10:21] gel site. Here's a fresh razor blade
[10:24] versus a used one, for example. And
[10:27] here's an old key versus a new key. You
[10:30] know, if you bend a wire back and forth,
[10:32] it eventually snaps. That's metal
[10:34] fatigue. And look under the gel site,
[10:36] you can see all these fishes near the
[10:39] brake point. This is a brand new foot
[10:41] scraper. And this is after it's been
[10:43] used.
[10:45] I'm sorry you had to see that. This is a
[10:47] scab and this is a scar. See how the
[10:51] scar tissue is smoother than the skin
[10:53] around it? Actually, cuticles look
[10:55] pretty gross, too.
[10:58] Look at the difference between young
[11:00] teeth and old teeth. And this is brushed
[11:03] teeth versus unbrushed. Actually, on the
[11:06] subject of toothbrushing, this is
[11:08] toothpaste. See how it's full of little
[11:10] hard bits that araid your teeth? And
[11:13] finally, we come full circle. This is an
[11:16] inter dental brush. And I guess this is
[11:18] your gums point of view. Kids, I think
[11:21] you need a new toothbrush. I don't know
[11:23] what it is about this microscope, but I
[11:25] just love seeing all the tiny structures
[11:27] of things with all the glare and
[11:30] transparency and color information
[11:32] stripped away. Maybe it's about
[11:34] understanding the world at a deeper
[11:35] level. Or maybe it's just how my brain
[11:37] works. And actually, if you've watched
[11:39] the video this far, maybe your brain
[11:41] works in a similar way. in which case
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