Kind: captions
Language: en
check this
out isn't that awesome that is
hydrodynamic
levitation check it
out this Styrofoam ball is levitating on
this stream of water and it's doing so
in a very stable way the setup is so
stable you can play Frisbee through
it which is weird to me because the
water is off to one side of the ball and
that doesn't seem to make any sense you
can block the water for a second and the
ball will still levitate have a
look Isn't that
[Music]
cool how can it be stable like this how
can this be a stable configuration that
is what we're going to explain this is
my friend Blake he is a toy inventor and
he actually came up with this and he
brought it to me and I was like that is
awesome there's some really cool physics
going on here juggling with water I
can't believe it
will just allow you to switch balls like
that they can even hit each other as
they go down each other and it doesn't
take the other one off the stream so how
does this effect work well a lot of
people might think of the hair dryer
pink pong ball effect which works
basically based on br's principle that's
actually what we're showing here we've
brought this stream down so it's going
at a very low velocity so it's pretty
much laminer flow and what you can see
if you look at the ball is it's entirely
enclosed in water so that water stream
comes up goes around the ball and just
as with the ping-pong ball if it moves
to one side of the stream it slows down
the flow of fluid and according to
Boli's principle this increases the
pressure relative to the faster flowing
fluid on the the other side so it pushes
the ball back into the middle that is
what provides the stability for this
ball but I think what we're seeing with
the bigger balls is something different
this is the largest Styrofoam ball I
could find so I don't expect it to work
but hey we're going to give it a shot
should I go
higher
oh it's
happening
massive that is incredible look at a
dance on there man
It's like got this inst stability but it
corrects it's incredible you should see
the way the water is spiraling off there
that is awesome
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so I've been thinking a lot about the
physics that makes this possible what I
think is happening is as the stream
contacts the ball it pushes it up but it
also pushes the ball out away from the
Stream So what I think is remarkable is
that the ball actually will stay there
it it is in a stable configuration and
from looking at the high-speed footage
what I really think is going on is this
water is getting thrown over and down by
the ball and since the ball is putting a
force over and down on the water that
water is putting a force up and in on
the ball which keeps it right in that
stream it's because there's a bit of
adhesion between the water here and the
styrofoam starts to go a little slower
that pulls all that water over the ball
and that's the start of how you get the
ball to spin and how you get that
sprayed down on the right hand side
which provides more lift and keeps
forcing the ball back into the stream oh
come
on once the ball is levitating it
remains stable because if it drifts too
far into the stream that decreases the
flow of water around the ball reducing
the force pushing it into the stream and
if it drifts too far out that increases
the water flow over the ball increasing
the force pushing it back into the
stream that's what makes the equilibrium
position so stable any slight
perturbation creates a restoring force
that moves the ball back to equilibrium
the rotation I think is also nice
because that gives it that angular
momentum providing a little bit of
stability side by side that's not not so
important for these balls but it
certainly is important for the disc if
you try to levitate a disc you need to
keep it in the right
orientation oh
yes getting the discs to levitate is
significantly harder than the balls
because they have to maintain their
vertical orientation in order for this
to work even a slight breeze makes this
very difficult
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hey check that out oh yes can you come
in and get
it oh my goodness here you go dude there
you
go this is a clear demonstration that
that is not just about the bruli effect
right it's due to the rotation of the
disc that actually carries the water
over and sprays it down which pushes
that back into the stream that's amazing
yeah not only is this an awesome
experiment it's also pretty fun to play
around with in the summer and it was
invented by my friend Blake so come over
to my channel in a Vinci and I'll show
you how with a simple Home Depot run you
can build this in your own backyard I
will put a link to that video right here
so if you want to make this go check it
out
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