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Language: en
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you're watching a Nova science Now video
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podcast in case you haven't noticed bugs
have been running the world for almost
half a billion years they outnumber us
200 million to one and make up over 80%
of known species and yet we spend over
$31 billion a year trying to figure out
better ways to kill them what if one of
these tiny pests had something amazing
to tell us about physics and if that's
not enough might inspire a new breed of
Robotics too take a
look Spider-Man may have made one bug
famous but what about this guy yeah
they're slow okay really slow but snails
do have some incredible
superpowers Spider-Man has nothing on
these snails MIT graduate student Randy
ewalt is out to discover their secret
check this
out they can even climb across razor
blades so what's the key to their
superpowers slime slime that's right
slime has this very interesting property
where it's a solid until you push on it
hard enough and instead of breaking like
a typical solid material would it
actually
flows snail slime is what's called a
yield stress fluid that means it can
behave like a a solid glue or a slippery
lubricant depending on how much pressure
you put on it so how does the snail
actually moving this stuff it's a good
question if you look underneath of a
snail you might be able to see waves
traveling from the tail towards the head
underneath each of these waves it is
liquefied the Slime so we want to test
it and so you need to find some way to
motivate the snails to crawl the thing
that I like to use is beer so what do
you do then you get the snails drunk
then then what put some beer down on the
end uh try to motivate them to crawl
around a bit um and as they're crawling
around I'll actually go in from behind
uh and scrape up the slime with a razor
blade like this uh and when I've
collected enough um I'll test
it what ry's found is that snail slime
isn't your mild mannered kind of matter
it's almost glue like at rest but as
soon as it's touched it turns into a
slippery fluid other things like
mayonnaise ketchup and peanut butter
have this property too but so far the
closest thing ry's found to snail slime
is carbomer a common thick agent used in
lotions and skin creams so what are you
trying to find we'd like to find an
artificial slime to use for robo
snail that's right Spider-Man you've met
your match Robos snam and he's not made
up in some comic book either Randy and
his lab partner Brian Chan are building
him in their lab is actually moving like
a real snail here yeah one section is
always moving forward and that's exactly
what a real snail does why would anybody
want a robotic snail well one is to
build robots who explore the body if we
make really tiny robots the fluids act
like mud or slime very viscous fluid so
a robot design like this would be very
good for that that means Robo snail's
next Quest might be inside you blood
acts like snail slime on a small scale
so if Randy and Brian can perfect their
work Robo snail successors could enable
some high- tech medicine like remote
controlled chemo or targeted blood
vessel repair all inspired by Nature's
lest little pest so what if there was
some sort of you know chemical spill in
here would you guys end up with super
snail Powers s man man the power of
slowness not bad for a little guy who's
gotten by half a billion years with a
single
foot for more fun science stories visit
our website at
pbs.org noova science now