workshop in the past grant has shown you
a pretty cool experiment that he came up
with that involved microwaving a large
glass jar with a little bit of water in
it
until it was really full of steam
pouring out the boiling water and
lowering the glass jar down into some
ice-cold water causes the water to
violently rush in and fill the entire
container we’re going to try and
replicate his experiment and then expand
on that idea with a couple other
experiments of making a vacuum in a jar
without using a pump to start off let’s
put a little bit of water in our jar and
then microwave it for a couple minutes
our glass bottle or out that hand so
it’s still filling with water but
because it took me so long to walk over
here from the microwave it’s not giving
us the explosive result we’re hoping for
it’s still pulling in quite a bit of
water though clearly we need to act
faster so let’s move our setup to the
kitchen and try again there wow yeah
that did a pretty good job of filling up
with water right there that was pretty
incredible I mean look how full this
bottle is that is a very full bottle and
so all of that water is displacing steam
that was inside this bottle so we can
see how much the steam shrinks as it
cools down that’s a lot that is crazy
there’s another method of creating a low
pressure inside a jar like this that you
may have seen before and we’re gonna try
and replicate again it involves lighting
a fire inside the jar and plugging up
the top to get our fire inside the jar
let’s take a strip of paper towel light
that on fire with the lighter and then
drop it down into the jar at that point
I’ll cover the top and we’ll see what
happens I took one of these gauges that
we use on our vacuum chamber to measure
the negative pressure inside our
container and I rigged it up so I should
be able to just pop it down on top of
this jar and if there’s any negative
pressure that forms inside it we should
be able to get a good measure of it
I started catching the flame burns out
we should begin to see our needle starts
to rise there goes that is not a lot of
rise we got our needle we are up to
about two and a half maybe three inches
of mercury that’s a pretty small result
but it is lower pressure see if it’s
enough to lift our jar it is is enough
to lift our jar buy pressure back in
that’s kind of cool you watch the
swirling air inside there try and get
our piece of paper towel out of the jar
that’s the fun part
a popular demonstration of what happens
when you create the lower pressure
inside the jar is to see if you can take
a hard-boiled egg which does not fit
through the neck of the jar light the
fire down inside and have the lower
pressure pull the egg through the neck
of the jar inside the bottle let’s try
and see if that work so we’ve got air
expanding inside there from the heat now
as it burns all the air up some
beautiful that just pulled it right down
into the jar that worked great so now we
have a jar full of smoke and an egg that
we can’t get out because it doesn’t fit
out of the neck there’s a whole lot of
remnants of our burned paper towel
inside the jar and I’m filling with
water and in addition to clearing out
the burn paper towel the water rising up
also does a great job of displacing all
of the oxygen less smoke that’s filling
our jar so it should be easier to do
this experiment again after we pour out
the water or we’ll try and pour out the
water in the egg yolk plug it up oh it
did well there is an egg plugging up our
jar it’s a pretty good plug right there
in an attempt to get the egg out I’m
gonna see what happens if I pour a
little bit of liquid nitrogen into our
jar then flip it upside down hopefully
keeping the nitrogen behind the egg so
the nitrogen will expand increase the
pressure and push the egg out
this might not work at all oh we did
that worked great now we have a jar full
of nitrogen gas as well our egg a little
worse for the wear being sucked into a
bottle and then blown back out of the
bottle so that worked pretty well and
now I want to try combining the two
ideas I want to put a little bit of
water in our bottle microwave it up so
it’s nice and hot again and then use our
pressure gauge on the bottle as we lower
it down into our iced water to see how
much of a vacuum we pull just by
shrinking the steam instead of replacing
it with the ice-cold water once our
microwave is finished cooking I’ll take
it out pour out the water I’m going to
add one large marshmallow down inside it
because marshmallows in a vacuum are
always fun and then I’m gonna put our
pressure gauge on top of the bottle and
lower it down into our ice water we let
it out fit a marshmallow in it doesn’t
have a lot of spare space there we go
now we get our negative pressure gauge
onto our container and start lowering it
down into the ice water to cool down all
of the steam inside the bottle you can
already see how much the gauge is
raising and if you look down into that
bottle you can also see our marshmallow
it’s starting to grow our marshmallow is
also very soft because it’s in contact
with our very hot glass oh wow we’re
already at 21 inches of mercury a pretty
big marshmallow it’s certainly a less
convenient way of making a vacuum
chamber than with our actual vacuum pump
but it is working all right I think
we’ve about hit our limit with our
vacuum pump at this altitude we can
usually pull about 26 maybe 26 and a
half so this is pretty seriously empty
there is almost nothing except that
marshmallow inside this jar here is an
unexpected marshmallow and are heated by
the glass and expanded marshmallow you
can see a pretty good sized difference
there now to break the seal I’m just
gonna pull up on the rubber a little bit
and it should be able to pop right off
smushed
now it’s just like a wrinkled melted
husk of a marshmallow there is one more
thing I’m going to try that’s pretty
similar I’m going to wash out this
marshmallow add a little bit of water
nuke this thing in the microwave again
and once it’s really hot I’ll take it
out and then I’m gonna see how many of
these eggs I can get it to suck down
into the jar as the pressure drops
cooling it down in our water in an
effort to get our jar to pull as many
eggs inside of it as we can
I’ve got a PVC tube that we should be
able to fit our hard-boiled eggs down
into in a line when the jar is ready I
should be able to flip the PVC tube up
put it over the neck of the jar and then
lower it down into the water and
hopefully as the steam cools off and it
forms a vacuum inside the jar it will
pull the eggs in one after another I’ve
never tried this before though so we’ll
see if it works there we go we can see
the eggs backed up to the pipe I think
we’ve got 10 eggs in this PVC pipe
hopefully we can get 10 eggs
[Music]
I think let me like the last one that’s
it that’s it well good news and bad news
bad news is we shattered our jar the
thermal shock I guess it was so hot and
then being dropped into the ice water
that just broke it right up but before
it completely fell apart we had enough
low pressure to pull 10 eggs through our
tube into the jar that was pretty
entertaining
that worked great but that’s never been
done before creating vacuum inside of a
glass jar with a couple unorthodox
methods we were able to drop a piece of
burning paper towel down inside and with
our vacuum gauge we saw that we pulled
about 4 inches of mercury which isn’t a
ton but it was enough that we were able
to lift the jar with it that low
pressure also had enough strength to
suck a hard-boiled egg down inside of
our jar which was entertaining to get
back out using a little bit of liquid
nitrogen poured in behind the egg we
also used boiling water and steam and
then cooled it off in ice water to get
the change in volume from the steam
being fully expanded to contracting down
a lot we were able to get a lot of low
pressure using that method we pulled
almost 25 inches of mercury just by
cooling our jar down in some iced water
that’s not a full vacuum but it is very
low pressure I thought it was very
entertaining taking our jar full of hot
steam lowering it down into some ice
water with a tube of eggs above it and
they all just got sucked down into it it
was really interesting I love that noise
it just pulling him down in we did
unfortunately have our jar shatter as a
result of the change in temperature from
the boiling heat to the ice-cold water
so unfortunately we were not able to
pour liquid nitrogen into the whole jar
full 10 eggs turn upside down and have
it just shoot them all back out which is
something I wanted to do and we might
have to try that again in the future
eggs are cheap steam is cheap overall
it’s a really cool experiment that shows
what kinds of vacuum pressure you can
get without owning vacuum pump
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