Kind: captions
Language: en
today I'm at the University of Sydney
with Dr Phil and we're talking about the
pressure that all of us are under you
are under a lot of pressure probably
10,000 kg 10,000 kg is pressing in on my
whole body all from all sides where does
all this pressure come from it's from
the
air that looks like a dance move on the
I'm lifting 10,000 kg of air you're
lifting the air how much air is there
above us about 20 km or so so you're at
the bottom of an ocean of air
so essentially the weight of the air is
squishing me in that's right and and all
of us you too and me too wow you seem to
be holding up rather well though thank
you thank you how do you do it what is
well I've got this special trick uhh
uhhuh I've got the same amount of
pressure inside me okay so since the
pressure is equal inside and outside of
you you're in equilibrium and there's no
sort of crushing or expansion no that's
right okay right well most people I
think don't recognize the pressure that
they're under at least you the
atmosphere that's right how can we
demonstrate that the atmosphere is
exerting this huge pressure on everyone
the best thing to do is to scoop out
their insides and then there'll be no
pressure on the inside and then they'll
be crushed crushed by The Atmosphere by
the atmosphere and that will be a rather
clear demonstration exactly of the power
of the atmosphere exactly but let's say
we didn't want to kill anyone uh how can
we demonstrate this in say a lab well we
could take a model of a person and this
drum is meant to be a model of a person
that's correct yeah okay and um so what
are we going to do with it so what we're
going to do is we're going to put some
water in here why don't we go ahead and
do it okay let's do
it get it heating
up so we've got some water in the drum
and we're heating it up on this uh
little gas stove here that's right okay
and what is that doing for us so the
water will heat up and begin to boil so
it'll turn from liquid into a vapor that
Vapor will push out some of the air okay
so basically we're going to remove the
air from inside the drum and replace it
with water vapor that's right okay okay
then once we're sure that it's pretty
much emptied of air we put the stopper
in mhm and cool it back down again okay
so that's going to condense the water
vapor that's right and so what does that
do to the pressure inside the drum it'll
become much smaller okay and then we're
going to be able to see what the
atmosphere does when there's no pressure
on the inside
push out ex exactly all right well I
look forward to that all right so how
long do we have to wait for this to boil
and get all sorted uh couple of minutes
mhm should we do a little time lapse
effect let's do that all
right okay looks like we're boiling away
furiously here is pretty good so uh it's
about time to perform the experiment
let's do it I but it might be a bit
dramatic so I'm going to uh Chuck on a
bit of gear safety glasses always
important y and safety gloves to avoid
burning your hands on this uh very hot
drum that's right now uh you might want
to you want to put those on I will you
might want to stand back a bit cuz it's
a little bit dramatic what happens all
right let's do
[Music]
it get to there and get some cold water
onto
it all right so that water's turning
back into water
vapor oh my
[Music]
God
[Music]
that's what you look
like with uh 3,000 Kg on your head
10,000 Kg on your whole
body you know I was expecting I was
expecting it to crumple like slowly over
time I wasn't expecting it to just go
all in once yeah well cuz it's CC little
bit of it goes and the whole lot goes
wow they're quite they're quite strong
for a while yeah that was awesome yeah
you can hear the air is trying to get
back
in
ah and now the pressure is equalized
there pressure is now requal that's
right wow that's one hell of an
experiment certainly is looks like you
wet yourself that was so
exciting that's partly
[Laughter]
true