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00:05
10:48
Science Max
Buoyancy Experiment
00:05 - 02:36
Phil demonstrates buoyancy using different types of fluids and different objects. He defines fluids and explains why air and solids such as sand can both be fluids.
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Video Transcript
0:06
buoyancy is the tendency for things to float
0:09
things like this balloon
0:12
or this ball in water
0:16
but
0:16
it doesn't float on its own but it doesn't float on its own
0:20
the helium is less dense than the air molecules around him and they fall past the balloon and push it
0:27
up the ball is less dense than the water around it so the water molecules flow around the ball
0:35
and push it up this happens because water is a fluid
0:39
the particles flow around each other
0:41
this works because air is a fluid and I know what you're thinking you're thinking
0:45
Bill
0:45
are is in a fluid but it is
0:47
usually we think of fluid as meaning a liquid but in this case fluid means
0:52
anything where the particles
0:54
can flow around each other
0:56
and that includes
0:57
are but you know what it's hard to see the particles in water same thing with are
1:01
I can say it but it's really hard to see it
1:06
now
1:08
yeah
1:09
now this
1:10
is sand and it behaves like a fluid to
1:13
well sort of check it out look
1:15
it's made of a whole bunch of very fine particles and it takes the shape of its container but watch this
1:21
I put a ball
1:22
in the sand
1:24
and it doesn't float now the ball is less dense than the sand but it doesn't float
1:29
because the particles of sand have a little bit too much friction right now
1:33
but watch as we move them around and reduce the friction by adding some are
1:39
now this and is behaving
1:42
like a fluid and the ball
1:44
floats let's
1:45
what else floats
1:46
on Sand
1:47
how about
1:48
this pumpkin
1:50
yep
1:52
that floats
1:53
how about
1:54
this block of wood
1:56
yeah that floats to
1:58
how about
1:59
this Styrofoam ball
2:03
yeah that definitely floats
2:04
look at that
2:07
the sand is a fluid right now because all of the little particles of sand
2:11
are moving around the watch this if I turn off the air
2:17
everything freezes in place
2:19
nothing
2:20
floats
2:20
anymore
2:21
because the sand is no longer behaving
2:23
like a flute so there you go
2:25
buoyancy it all depends on the density of the thing
2:28
and the fluid it's surrounded by
2:32
science
Rebecca S Schlafer-Miller