In Star Trek IV: The Voyage Home — ever seen
it? Came out in 1986? The crew of the original Enterprise go back
in time? To … 1986? Anyway, there’s a scene where chief engineer
Scotty describes a lighter, sturdier, futuristic alternative to plexiglass: transparent aluminum. This stuff is supposed to be so strong that
it makes up the viewports of the Enterprise. The coolest part though, is that this stuff
is not just science fiction! Transparent aluminum actually exists, and
it pretty much lives up to Scotty’s hype. And it’s just one of many cool new materials
that seem like they were plucked straight out of science fiction. From invisibility cloaks to self-repairing
concrete, the future is now. [Music Playing] Aerogels are one of the lightest solid materials
in the world. Gels are mostly liquid, but they act like
solids because there’s a bunch of molecules in them that link together and hold the liquid
in place. Aerogels are gels where all the liquid has
been replaced with gas. Imagine taking your favorite gelatin dessert
and sucking out all the water. But instead of crumbling into a powder, it still keeps
its dome-like shape. That’s basically how scientists create aerogels: First, they make a gel out of something like
silicon or carbon compounds. Then, they use extremely high temperatures
and pressures to blur the line between the liquid and gas phases, creating a supercritical
fluid. Then the kinda-liquid-kinda-gas can drift
out of the solid molecular structure, and be replaced by air, so you have a porous,
lightweight material that retains its shape. Aerogels are great for insulation, because
the air inside doesn’t transfer heat very well. So they’re mostly being used in spacesuit
and spacecraft linings. Plus, they’re almost transparent, which
means we could use aerogels to insulate windows here on Earth… when they get cheaper. If you’re a Harry Potter fan, chances are
you’ve wanted your own invisibility cloak. But instead of using magic to make things
invisible, muggle researchers need to experiment with light. We don’t have large-scale invisibility cloak
technology yet, but scientists are working on a lot of different ideas, like creating
flexible sheets of liquid metal that can block radio waves used in radar. And we’re getting closer. In 2015, scientists designed a very, very
thin material, like, 80 nanometers thin, that could hide equally tiny objects. In order for us to see an object, light has
to bounce off of it. And any distortions of that light reveal its shape and features. This invisibility cloak uses teeny-tiny brick-shaped
gold antennas to counteract that natural light distortion. So when this cloak is wrapped around an object,
any light bouncing off of it looks like it’s coming from a perfectly flat mirror, hiding
the fact that the cloak and object are even there. And theoretically, you could adjust the gold
antennas to make the reflected light look like any object or background. This technology only exists at a microscopic
level right now, so scientists need to figure out how to scale up the idea before we can
make larger objects, like people, invisible. So we can’t quite make objects invisible,
but what about super waterproof, or superhydrophobic, materials? I’m talking way more waterproof than your
average raincoat. Scientists are trying to find ways to mimic
the waterproof surfaces found in nature, like the lotus leaf or certain butterfly wings. And it turns out that microscopically rough
surfaces tend to be more hydrophobic, because they can trap pockets of air and minimize
the interaction between water droplets and the surface of the material. So scientists can make coatings that have
things like aluminum oxide nanoparticles in them, to make surfaces rougher and repel water. Another idea is to make surfaces that are
covered in itty bitty ridges or polymer cones, that are just tens of nanometers in size,
thousands of times smaller than the width of a human hair. These materials are so waterproof that water
droplets actually appear to bounce off of them, and even split into smaller pieces! By putting this stuff on electronics and medical
devices, we can protect them from water damage, but these materials may also be someday used
to keep ice from forming on cars, or algae growing on ships. Carbon is… amazing. Like, the-basis-of-all-life-as-we-know-it amazing. We’ve talked before about how awesome some carbon-based materials are, like graphene. But we can use what we know about carbon to
make a material even harder than diamonds. Aggregated diamond nanorods, or hyperdiamonds,
if you wanna sound cool, these are the hardest, most dense, and least compressible material
we know of. Diamonds are hard because of their molecular
structure, each carbon atom forms four covalent bonds with the atoms around it, which forms
an exceptionally hard crystal structure. In hyperdiamonds, that’s still true, but
it’s a different, more wear-resistant form of diamond. This material is made up of many tiny, interlocked
diamond crystals rather than one single structure. They can be made in the lab by applying extreme
heat and pressure to graphite. Diamonds are frequently used for industrial
jobs like grinding and polishing, because they’re so tough. But hyperdiamonds could be even more useful
than regular diamonds, because they’re even more resistant to the temperature and pressure
changes that can wear diamonds down over time. Now, when can metal also be glass? Well, when engineers invent … metallic glass,
also known as amorphous metal. Most metals have a crystalline structure,
the atoms are ordered into a specific, repeated pattern that makes it stiff. But glass has a random arrangement of atoms,
which makes it more brittle. So, metallic glasses form when metal atoms
are in this random arrangement, like when melted metal is cooled really, really quickly,
before its particles can arrange themselves into a crystal. This material has the best of both worlds,
the malleability of molten glass combined with even more strength than crystalline metal. This combination of high strength and low
stiffness makes it really resilient, it can store and release elastic energy better than
other forms of metal, which means it doesn’t deform as easily. Right now metallic glasses are being used
as coatings to make objects more corrosion or wear-resistant, or to make products like
golf club heads. But eventually the material could be used
to easily manufacture things where strength and weight are concerns, like lighter, stronger
car parts. But glass isn’t the only hot new metal material. Metallic foams are made up of a metal, like
aluminum, and a whole bunch of gas-filled pores. This makes them super light, plus they keep
many of the original properties of their metal, like being strong, fire resistant, and conducting
electricity. Metallic foams can be made a few different
ways, like by injecting gas into a liquid metal, or by causing the precipitation of
gas that’s already dissolved in a metal mixture. And some are open-pored, meaning that the
gas pores inside are all interconnected, creating what are sometimes called metal sponges. But in closed-pored metal foams, the little
bubbles are all separated, which means they can float in water, which could be helpful
for building sturdier, lighter boats and spacecraft that can make water landings. In general, metal foams are useful for high-tech
shock and impact absorbers, the gas inside makes them extremely compressible, so they
can absorb a lot of mechanical energy, while still retaining some of the strength and durability
of a metal. This means they also have a lot of potential
for building different car components that are light and sturdy. Some metals also have unique new uses, like
aluminum. In Star Trek IV, it’s called transparent
aluminum, but that’s kind of inaccurate. The material our scientists are manufacturing
is really aluminum oxynitride and it’s composed of aluminum, oxygen, and nitrogen. It’s a ceramic, which means the material
starts as a powder, and is then heated up until it melts, and then cooled into a crystalline
structure similar to glass. It’s basically transparent, and extremely
strong, nearly as hard as sapphire, so aluminum oxynitride is really useful for things ranging
from bulletproof windows to super-durable camera lenses. It’s still expensive to make, but hopefully
we’ll find ways to make it more efficient by the time we get around to building starships! Concrete! I’m sure you’re
familiar with it. Just today, you’ve probably walked on it, or sat on it — in
fact, it’s probably all around you right now! But as materials go, it’s not very… cozy. The invention of light-transmitting concrete
hopes to change that, by interspersing very thin layers of concrete with optical fibers. This means light can be transmitted from
one end of a concrete block to the other. The translucent concrete maintains most of
its strength, so it can still be used for heavy duty projects, like constructing buildings
or roadways, or it can be used in otherwise difficult-to-light areas, like subway tunnels
and walkways. Unfortunately, we haven’t found a way to
pour this stuff out on-site like traditional concrete, which means it’s not really practical
yet, mostly it’s used in art installations or very small areas. But with some more research, fancy glowing
sidewalks may become the new normal. Now, what if we could increase the lifespan
of concrete that’s already been poured? Enter: self-healing concrete. Invented by scientists in the Netherlands,
the basic concept is to combine engineering with microbiology, and embed bacteria that
can create limestone directly in the concrete. During normal seasonal changes, concrete shrinks
and expands and eventually cracks. Then water can seep in, causing even more
damage. But self-repairing concrete, contains biodegradable
capsules that are full of bacteria and their food source, in this case, calcium lactate. The bacteria lie dormant until the water seeping
in dissolves the capsules and sets them to work, eating and multiplying and producing
calcite, or limestone, from the calcium lactate, which fills in the cracks. These bacteria can survive up to 200 years
if there’s enough nutrition embedded in the concrete. Currently, the bacteria can only heal very
small cracks, but eventually this technology could fill larger breaks, which could be huge
for fixing roads and building more durable buildings, without hands-on construction time! So, scientists are developing all kinds of
new materials with incredible properties and weird new uses. Soon we’ll be building the future with all
these technologies, and more. Someday, Scotty will have been proven right! Thanks for watching this episode of SciShow,
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