 ( music playing )
What on here do you have that
changes or controls how much
you're going up and down?
I have no idea--
no, I'm just kidding.
So, I brought some experiments
that I want to show you
to talk about
the pressure change.
Because you're going up
in the atmosphere
and the pressure
gets way lower.
I want to
show you an experiment
to talk about that,
about the fact
that the air gets thinner.
- Okay.
- This is a vacuum chamber.
And then I'm just going to--
I'm not even going to
blow this balloon up.
I'm just going to tie it.
Okay.
So, I'm going to turn
the vacuum pump on.
That little balloon
at the bottom
is the one that
I didn't blow up at all.
- That you did nothing to.
- Yeah, and it's
  already mixed in.
- But these ones already
  have so much gas in there.
- That's so cool.
The reason I wanted
to show you this
is because the first thing
I thought about
when I saw
these massive balloons
is the fact
that these will expand.
They'll go from about 8 feet
in diameter to about 10 feet
because they do
the same thing
as these balloons.
So there's more drag on them.
There's so many things
that go on.
It'll look bigger,
but the issue is
if they start popping,
that's a real--
Yeah, if they're just
closer together and touching.
- What happens in your blood?
- Slightly different thing.
But we have
an experiment for that
if you want to do that one.
- Yeah, great. Perfect.
- Okay. Yes.
 Dianna: I was curious
 when I heard you were going up
fast you're going
and how high you're going,
because that determines
whether you would get
decompression sickness.
There's a syringe
with some fluid in here.
I'm going to pull it back
and you'll see what happens.
- What fluid is it?
- I'm going to have you guess.
  Okay, here we go.
So you can see it
continuing to bubble.
I'm just holding it here.
- It's continuing to bubble.
- So it's like carbonated water.
- Amazing! Yes.
- Is that what it is?
- That's awesome.
- That's exactly what it is.
  So you pull it back.
- It keeps bubbling from
  all over in the fluid.
- Wow.
And then you let it go
and it stops.
- So this is exactly what--
- What happens to your blood.
More with divers,
is decompression sickness.
Because you go down
and the more pressure
you're under,
the more you can get nitrogen
dissolved into your blood.
I mean, this is like
a really quick and drastic
pressure change.
- So if that happened to you...
- That's bad.
- That would bad.
- Yeah.
- This is 17 pounds of lift.
- Yeah.
So if you feel this one--
feel it.
- They're so hard to pull.
  That is incredible.
- It's amazing, right?
So basically,
if I had seven balloons,
you'd be good to go.
So, like,
seven or eight balloons?
That's so cool.
So, you're using helium,
which is a great gas
for flying with balloons.
But hydrogen gives you
a bit more lift because
it's less dense.
Helium is much more difficult
to come by and more costly.
I wanted to do
a demonstration with you,
and I wanted to show you
why you're using helium
and not hydrogen.
So we have some hand sanitizer
wrapped around a stick.
That is going.
Test number one. Helium.
It's basically
what we expected.
Was that one clap
I heard over there?
So, now we are going to do
the hydrogen test.
- Whoo!
- ( crew cheers )
- That was so good.
- We did it.
So that's why
you avoid hydrogen.
 - Boom.
 - Wow.
 ( slowed ) Ooh!
- That is awesome.
- Yeah, that is awesome.
- Thank you, that was...
- ( indistinct chatter )
