a portion of this video is sponsored by
google more on that later here on
smarter every day i like to explore
things and i like to figure them out for
myself and there's one thing that you
can do with the internet that's really
cool you can just go find knowledge
wherever you want it but what i like to
do is figure things out for myself
that's like the sweet spot between the
unknown and knowledge right that
discovery exploration phase that's what
this video is a couple of weeks ago my
buddy sent me this video of him moving
his hand over some grass in his backyard
and these little seeds were exploding
all over the place now i've heard of
grass that does this but i have no idea
how it works and i resisted the
temptation to go search for it i just
want to figure it out for myself now
what i want you to do is i want you to
resist the temptation to just fast
forward to the slow-mo i want you to go
along on the trick with me and explore
how this is working and realize that
along the way i'm going to say things
that are wrong so let's go explore
backyard grass seeds exploding with a
high speed camera and let's see if we
can learn something together well first
of all i want you to see this guys
azaleas look at these
they're awesome they smell like a really
pretty grandma if that makes any sense
if your hand goes over it
i don't even know if you can see this
on video because it's happening so fast
but if this
grass is mechanically disturbed in any
way
it explodes and it throws grass seeds up
and i think it's too fast for this
camera which means we're gonna have to
look at this with a slow-mo camera so i
think what we're gonna do is we're gonna
start with a wide-angle lens
and we're gonna try to find out at what
point on the grass stem the seed is
shooting from and then after that we'll
go to some macro lenses and then we'll
try to hone in on exactly what's
happening and eventually find out the
mechanism for ejecting the seed so let's
try this
okay i don't know if seeds
flew off or not but we're gonna look at
that
oh okay
oh
it's coming up from the tassels we at
least know the region of the grass that
it's happening in we have figured out
that the seeds are blasting out the top
of the grass we figured out that my hand
is in the way we're also going to
transition from the 35 millimeter lens
to the 85 millimeter lens which should
give us
a tighter shot and we should be able to
lock in on this thing better okay i'm
gonna try to trigger it from the back
trigger the the grass from the back and
trigger the camera from here so here we
go
okay let's see we got it's so silly but
my heart is beating fast over grass
seeds
[Music]
it's at the base of where the tassel
meets the main stalk
i think i'm running the camera too fast
i can slow it down i can let more light
in and i can get a deeper depth of field
because i'm struggling with stuff in and
out of focus
okay
i'm not framing it well
and the problem is they're flying into
the field of view and out of the field
of view so they're in focus for a very
short amount of time it is literally
easier to film missiles and rockets than
these grass seeds okay this just got
serious i had to go get a light
all right we'll see
oh
oh it's out of focus it all comes from
one
shot okay if i can find that i can
figure out how to do this
we are getting close
and i'm excited this is a fast event
that was 10 000 frames per second this
is a really really fast thing okay
we are honing in on this thing all right
so
obviously i don't know what i'm doing i
don't know what triggered i'm looking at
that
and i'm looking at this
and i don't know what happened
we got to get this i'm going to touch
that
oh
man
it's a reverse banana peel slap bracelet
okay this is how i think it's working
get a slat bracelet right these are
awesome you had them when you were kids
really fun and these slap bracelets are
kind of on the side of the banana i know
this is ridiculous but this is what i
think is happening so if you were to
connect up at the top of the banana here
and you were to activate that slat
bracelet somehow on both sides see if i
can do this
check that out that's pretty cool those
slat bracelets roll up and then they
fling the seeds off when they go that
seems to be what's happening here turns
out this plant is well described in the
scientific literature arabidopsis
thaliana i think is what we're dealing
with in fact i found this really cool
document morpho mechanical innovation
drives explosive seed dispersal and it's
really really fun so anyway slap
bracelet banana once i understood the
geometry of what was going on here i
could really focus in on it and make
some really serious observations i
started by trying to vibrate the grass
and then eventually i settled on using
my knife to trigger it in various ways
sometimes i would cut the stem and other
times i would try to tap it but
eventually i settled on using the pretty
azaleas as a backdrop to make the shot
as pretty as i could make it
[Music]
shut up the seeds are sticking to it as
it's rotating and then
as it curls in tighter and tighter
it the the rotational velocity
oh my goodness
it does the the figure skater thing it
starts wide as it curls up tighter and
tighter the radius gets smaller and
smaller angular acceleration goes
through the roof which disconnects it
from the p-pod we understand
[Music]
do
[Music]
there's all kinds of crazy stuff going
on in this footage when you look closer
when i looked at this one particular
macro shot again i realized there were a
few small red bugs on the pod when it
exploded and one of those little ones
with flying
[Music]
i decided to measure the length of one
of the pods with some calipers and use
it as a fiducial or a reference
measurement to calculate the velocity of
each seed as they're being thrown off
there is so much to see in this data for
example the location of the seed within
the pod it seems to determine how fast
it is it looks like the first seeds to
launch go the fastest furthermore the
direction that each seed goes seems to
be a function of the stickiness of the
seed to the pod curl if you look as the
radius of the pod tightens it seems like
that helps it peel the seed away from
the inner surface and because each seed
detaches at a different time the spatial
distribution is all over the place which
is a function of the stickiness and the
curl but all that is good if you're a
plant you want your seeds to go in many
different directions all of this feels
like chaos but it's not
there's just a few simple principles at
play that almost randomized the seed
distribution the design of these little
seed pods reveals tremendous mechanical
mysteries if you're willing to look
close enough all right i've got one more
slow-mo shot to show you but before that
this portion of the video was sponsored
by google one thing i'm really serious
about here on smarter every day is
combating misinformation in fact i did
an entire video series here on social
media misinformation and how that
affects you i want to talk about being
smart and thinking critically when you
search for information online when you
use google to search for something it's
important that you do it in a smart way
google search function is a tool and
just like any tool there's a smart way
to use it as a part of their civic
online reasoning program the stanford
history education group has identified
three questions to ask yourself when
looking for information online the first
question is who is behind the
information i don't know if you knew
this but every time you conduct a search
on google there's these three little
dots that pop up at every single result
and if you click those it'll expand and
give you more information about the
website that's serving you the
information the second thing to think
about when you're figuring out who's
behind the information is kind of in
your head let's say you want to learn
about these islands right here in south
america if you were to search for the
term falklands you're going to get one
set of perspectives but if you use the
term malvinas which is the argentinian
term for those islands you're going to
get a completely different perspective
because those islands were the subject
of a major conflict between two
different groups of people think
critically about what you're searching
for in how you conduct the search and
when you get the information think
critically about the results you get you
have to search for information in a
smart way if google search is a tool you
have to use the tool well and be smart
about it so yeah that's a really big
deal and i'm super passionate about it
so thank you google for sponsoring this
portion of the video okay at this point
i have been doing this in the backyard
for maybe seven hours so i want to just
for a grand finale step in a big patch
of this stuff and watch it all fly up
now that we understand the minute
mechanism at work so here we go we're
gonna waste all these at one time should
be pretty cool
[Music]
i thought this mechanism was incredibly
clever and i really enjoyed exploring
this so i hope you enjoyed the path of
exploration trying to figure out how
this little thing worked i'll leave a
link down to that scientific research
paper it's fascinating how this little
guy works i i just love it so please
consider subscribing to smarter every
day if you're into that sort of thing
but if not i don't care i just want you
to go outside and look at the world a
little bit closer and see all the beauty
and wonder that's around you thank you
so much i'm destin you're getting
smarter every day
have a good one