Cold Cuts! No baloney!

Just science!

I'm a little bit afraid to ask this next question

because I think I already know the answer,

but is anyone in here feeling a little... dangerous?

You're willing to take a chance?

Because I am willing to do an experiment they haven't let me do since 'The Incident.'

Now, because of the danger, I cannot have a volunteer. I must do this on my own.

[Audience] Awww...

And, because of the lawyers, I need everyone to raise their right hand and repeat after me.

Say 'I promise.'

[Audience] I promise.

Not to try this at home.

[Audience] Not to try this at home.

I promise.

[Audience] I promise.

Not to try this at someone else's home.

[Audience] Not to try this at someone else's home.

What I'm going to do, I don't want to hear stories on the news about this.

I'm going to take a match,

gonna light it,

and then I will light this candle.

And then...

we'll take the fire and put it in here.

Now, the way I see it, there are a range of possible outcomes.

Maybe when the fire gets into the nitrogen, it doesn't care and...

or it doesn't like it and the fire goes out.

Maybe when the fire gets to the nitrogen it doesn't care. Keeps on burning just like it is.

Maybe when the fire gets to the nitrogen, it likes it. Burns brighter.

Or maybe it likes it so much we get another little explosion out of it.

So, let's take a vote.

Who says fire goes in, fire goes out?

Who says fire goes in, fire stays the same?

Who says fire goes in, fire burns brighter?

Who says fire goes in, fire explodes?

Who, deep in their hearts, wants it to explode?

That's what I thought.

Okay, before we do this, direct your attention to the back of the auditorium, please.

Fire exit.

Fire exit.

If you get blown against the back wall,

if this door is unlocked, it's a fire exit.

Um, if you happen to get past the second camera and get blown through that window,

go ahead and unlock the door so folks can use that.

Over here, this side, fire exit.

And, of course, where we came in from is a fire exit also.

Around the corner, should it be needed,

we have a phone so we can call the fire department.

And inside the little wall...

we have a fire extinguisher...

so you can, like, put me out, please.

Now...

one thing that some people won't like,

not wearing those, because gloves burn.

And when they're on your hands on fire, it's not a great deal of fun.

One thing I am going to do, though, is leave my goggles on,

because it turns out that eyebrows take, like, three months to grow back,

and it's just somewhat embarrassing.

Now, the hardest part about this is, is yours.

I need absolute silence when I do this,

because I'm not sure what happened last time.

Well, I know what happened, I don't know why it happened.

So I need to concentrate as I do this,

because we really don't want a repeat of what happened last time.

Okay.

Closer...

Ummm.

Front row people.

Do you know anybody in the back?

I think that's a different school back there.

People in the back, this is important.

You need to decide now: duck, catch.

Sometimes we have younger kids in the front and older kids in the back,

but this time it's all one grade,

so it not like you have a third grader coming whipping at you.

Okay?

So you've got to decide if an eighth grader comes flying past,

either let them hit the wall, or attempt to catch.

But you don't want to get caught in between.

Okay? Decide now what your plan is going to be.

Oh, and I'm forgetting.

Sorry, sorry, sorry, sorry, sorry, sorry, sorry.

Because it gets a little loud.

Just because I have these on doesn't mean I can't hear.

Okay? I don't go deaf when I put these on.

So you still need to be quiet, still need to not make 'Boom!' noises or anything like that.

Nothing to freak me out during this.

Okay, guys.

Here we go.

Gonna get it closer...

Closer...

Okay, here we go for real!

No more playing around.

And it went out!

What a rip-off!

We'll do it again.

But this time,

instead of using all the nitrogen inside the container,

I'm going to pour a little but out into the cup.

That way, if there's a problem,

it's a little problem instead of a big problem.

And, to further increase my own personal safety,

I'm going to point the cup towards you.

So anything bad goes in your general direction.

And it went out.

Why's it going out?

[Audience] No oxygen!

Excellent! Most people say it goes out because it's cold, which is not right.

I can stick my hand here...

and my hand doesn't get frozen

because the liquid is way down here.

At the surface of the liquid it's 321 degrees below zero,

but the closer to the top it is the warmer it gets.

I can tell by looking that at the very top it's above freezing

because there's frost in the container.

The frost doesn't make it all the way to the top,

so I know where the frost ends, above that point it's above freezing.

In fact, at the very, very top where it was going out,

it was, it was warmer at the top than it was outside this morning coming in.

It's about 55 degrees right at the very, very top.

So I can stick my hand in there for as long as I like

and it doesn't freeze and shatter, which is nice.

Why does it go out?

[Audience] No oxygen!

There's no oxygen!

Yeah, when liquid nitrogen boils, what does it make?

[Audience] Nitrogen!

Nitrogen! It makes nitrogen gas.

This whole container fills up with nitrogen gas.

There's no oxygen in there.

So if I shove a fire in there and there's no oxygen, the fire goes out.

If I shove my face on there and there's no oxygen, I go out, which could be bad.

This is a problem that we have.

This is a problem with the nitrogen, it's a problem with the helium that we have in our tunnels.

If it ever gets out, you get big bubbles of helium drifting around inside the tunnel.

You can't see the helium. You can't smell the helium.

You can breathe it if you want. Helium's not poisonous.

But if it displaces too much oxygen, you're going to have big problems.

So inside the tunnel we have oxygen sensors to let us know what the level is

and if the oxygen level goes too low alarms go off so everyone can go running away

from the big bubbles of helium that are trying to kill them.

Keeping in mind that you should run away from big bubbles that are trying to kill you,

I need two more, two more somewhat brave and slightly foolish...