Kind: captions
Language: en
So today I'm at the University of Sydney
with Steve Boosezie and we are exploring
everyone's favorite state of matter, a
plasma.
Well, actually my favorite state of
matter is the Bose Einstein condensate,
but that's just me.
That's for another episode. So for now,
we are trying to replicate these videos
that you can see on the web where people
use a simple grape and a microwave to
produce plasma.
We took a grape and cut it part of the
way through so you'd have two halves
with a tiny little ismas of grape skin
holding the two halves together. Put
that in the microwave oven. Now try to
prop that up so it's sitting in the
middle.
All set.
Is this going to be dangerous?
Uh, I don't think so. But, uh, we are
experts, so be careful if you're trying
this at home.
And bingo.
Where's the plasma?
Whoa.
Whoa. There there's the plasma.
Oh.
Hey.
Wow. Well, that was some pretty amazing
plasma that we made in this microwave.
Um, what is plasma for people who don't
know?
Okay. If you take a gas and you put lots
of energy into it till it gets very hot
and the particles are very, very
energetic, you start to rip electrons
off the molecules. So, you end up with a
soup made up of negatively charged
electrons mixed in but moving freely
with a bunch of positively charged um
air molecules. And why does that give
off light?
Well, anytime that you put energy into
atoms and molecules, the electrons start
moving around, changing orbits, and that
kind of stuff. So, anytime the electrons
are being excited and and and deexited,
you're going to get light.
Whoa. Who needs drugs?
And we also imagine that it's very hot.
So, it would be glowing white hot
anyway.
Yeah. Possibly. Also, some of the
ingredients in in that plasma uh have
actually been heated up very high, so
they're incandescent. They just glow cuz
they're hot.
Don't know.
So, so what did we find worked the best
with microwaving our grape? What lessons
did we learn?
Okay, first thing we discovered was we
got better results if we dried the grape
up before we put it in. We found too
much water gave off too much steam. They
tend to extinguish the the plasma.
And then Steve came up with a great idea
of actually uh cutting the grape
completely in half, but using these
dangling flaps of uh grape skin
and grafting them together, just laying
them over the top of each other.
And that seemed to work better because
we could reduce the volume of the grape.
And that seemed to to help.
Yeah. But because we used smaller pieces
of grape, so we had less steam, also
less thermal mass and possibly more less
grape absorbing less microwave energy,
so we got higher fields.
Oh,
holy
species.
Oh yes. Did you see that fireball?
That that was an example of multiple
plasma.
And then of course the trick was to try
to capture the plasma so that we didn't
do damage to the microwave for one thing
and second of all so that we could
observe it quite nicely in in a
container but we had trouble with the
glass that we were using the few glasses
to get it to work.
The guess is that the glass was
absorbing too much of the microwave
energy and so we weren't getting the
very high fields you need to make the
plasma.
Oh yeah.
Oh no.
So we moved over to a plastic container
which seemed to do much better.
Yeah. If you can just tolerate the fact
that the plastic container melted
afterwards.
Plastic container to capture the action
and adventures.
Look
what
go. The laws OF PHYSICS.
YEAH.
OH [screaming] YEAH, IT'S STILL GOING.
[laughter]
Gods
of physics.
Yeah.
[screaming]
Yeah.
It's still going.
Do you smell that? Is that a new smell?
Is that a melting plastic?
Are you still filming?
Oh my god. Hang on. Catch that. Look,
it's got a smile. Even this Even the
container's got a smiley face after that
run. [laughter]
Yeah, it's uh it was only like a one hit
gig. So, uh what sort of future
investigations would you like to do
here?
Okay. Now, in order to to understand
exactly why this happens, um we really
need need to be able to control the
variables inside that grape. Okay. We we
we can't control the ingredients of a
grape. They come to us as is. So, what
we'd like to do is make a an artificial
grape. So, we I don't know get cotton
balls. We can put uh conductive liquid
in it. You know, we can put salty water
in it. We can put grape juice. we and
and control the volumes of these things.
So, one by one we can actually um nail
down the different uh variables and
we'll have to find some some artificial
skin to replace the grape skin. I don't
know if it has to be grape skin. Maybe
maybe a wet piece of paper might do the
job. I don't know.
Okay. So, you should look forward to
that on another episode of Veritassium.
Care for a grape.
Thank you very much.
Physics is tasty.
Holy.
[screaming]
Oh, see what did I tell you? What did I
tell you? [laughter]
But wait, there's more. No, there's the
epic visit.