Hi everyone, welcome back to Cody's Lab
so you may have seen the party trick where you take a glass bottle
fill it most of the way up with water and then smack the top.
As you can see that blows the bottom right out of the glass.
So what happens here is we
shove the glass downward so fast that
the inertia from the water keeps it more
or less in place and that creates a
vacuum bubble beneath the water and then
when the glass stops moving the water
slams back down into the glass creating
a sharp water hammer effect which blows
the bottom of the glass right out.
So this got me thinking what if I used
mercury instead of water you see right
here is 15 pounds of liquid mercury
mercury is so much heavier than water
that I would expect that if the water is
left behind mercury will get left behind
even more and mercury has a lower vapor
pressure so the vacuum will be even
harder.
So theoretically mercury should be the
perfect material for this.
Why don't we put mercury in the bottle and
find out. It's significantly more heavy
this time, so let's hold it right there and
then smack the top, that's a lot of mercury
good thing i got it contained in this big
dish and here we go.
I didn't even hit that hard.
Just a little tap and it just shoved the bottom right
out of that bottle.
Excellent! That was perfect! Did you catch it?
I'll get my sleeve here...shake everything off. All right.
Let's check the high-speed.
So, watching this high-speed I don't
really see a cavitation bubble forming
at the bottom of the bottle but i do
eventually see the bottle break at the
bottom so I suspect what's happening
here is the mercury is like sticking to
the sides of the glass and you just
can't see the cavitation bubble. But Man the
the splash when the mercury hits the water
sure looks amazing doesn't it, I did this
into water so that the water would
splash and not the mercury. Ok so this
time I have roughly the same mass of
mercury as I did water as you can see
mercury takes up a lot less space for
the same mass because
it is so much more dense let's see if we
get the same effect as we had with water
lickety-spit it shoved it right out
well that's messy that time too.
Okay so now we've proven that mercury
does indeed below the bottom of the
glass much better than water does in
fact I want to try something that I've
always been told not to do. You see I've
been told that if you shake a glass
bottle with mercury in it that I could
cause a cavitation bubble at the bottom
and cause the mercury to shatter the
glass and I'll see if I can recreate
that here so. I'm just going to vigourlously shake this
maybe not so much that it throws mercury
everywhere
let's see if I can get the mercury to
break the glass.
So, I'm not going to hit it just gonna shake it
Ready on the Camera?
it seemed that no matter how hard I
shook it, the glass wouldn't break
due to the mercury and I think it's
because when I shove it down the mercury
like kind of flows out and around and it
would let air get down underneath of it
and then when the mercury slammed back
down there air would cushion it maybe if the
right conditions happened it would break
the glass but I couldn't recreate it
here today. To finish off I'm gonna break
this one more time with a little bit
wider shot on the high-speed so until
next time I'll see you then. So I put some
more mercury in there along with a little bit
of water. Lets hit this again and see what it does.
Now it broke.
Did you stop it? Ok, now we're done.
[music]