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Liquid Nitrogen Show!

All of your favorite liquid nitrogen experiments all in one place! Flowers! Balloons! Racquetballs! Nothing is safe! Just sit back, relax, and enjoy the show!

Announcer: Frostbite Theater presents... Cold Cuts! No baloney!

Joanna and Steve: Just science!

Joanna: Hi! I'm Joanna!

Steve: And I'm Steve!

Joanna: Usually, every couple years, Jefferson Lab hosts an Open House. This is the one time the public and come and tour our accelerator and end stations.

Steve: During the 2010 Open House, our cameraman snuck into one of the ongoing cryo shows that are held throughout the day. He missed half of it. So if you want to see the entire thing, check our website to see when the next Open House will be.

Joanna: Until then, enjoy!

Steve: Who would come down and stick their hands in?

Okay, but before we do this the two of you put on goggle and put on gloves.

While they are getting goggles and gloves, what are these?

Audience: Flowers!

Steve: Flowers! These are the flowers of science. Are these hard, soft, real fake?

Audience Member: They're real.

Steve: The nice people on this part of the front row says that they are real. Do you trust these nice people?

Audience: NO!

Steve: Poor nice people...

These are nice, real flowers. They're nice and soft. What I propose to do, before we have our volunteers put their hands in the nitrogen and possible get hurt, I say we put the flowers in first. If the flowers turn out okay, then we'll make them put their hands in. Does that sound fair?

Audience: Yeah!

Steve: Good!

What is taking you so long?

Whoops.

There you go.

That's the whole point of the goggles, so you can't see anything.

Okay, which one do you like? Good. Which one do you like? Good choice.

Ladies first. Come on over here.

Stand right over here.

Hold the flower by the very end of the stem.

And, when I tell you to, very slowly...

You okay? Okay.

Very slowly and very carefully put the flower into the nitrogen. Everyone else listen, see if it makes a sound. It's like a sizzling toilet flush? Why is it making that sizzling sound?

Audience: It's boiling!

Steve: What's boiling?

Audience: The flower!

Steve: The nitrogen! Because...?

The flower's too hot. The flower's room temperature. And it goes into the nitrogen and the nitrogen goes "That's a really hot flower!" The nitrogen boils, goes into the air, and we end up breathing the stuff.

Very carefully take it out please. And hand it to me.

Is the flower okay?

Audience: NOOOO!

Steve: It still looks like a flower. It's just a little bit foggy, but that's okay.

All right, you stand right over here. And face them. I'm going to hold this over here like this. And you take your hands and squeeze that nice, soft flower.

Flower: -crunch-

Steve: Squeeze it.

Flower: -crrrrrunch-

Audience: Oh!

Audience: Yay!

Steve: Yeah...

Okay, you hold this.

Now, in science, normally you don't do an experiment just once. Do an experiment once and if something weird happens, you don't know if that was suppose to happen, or if it's her fault somehow.

You take a few steps this way. And you come in over here with the emergency back-up flower.

Stand over here. Same thing. Carefully put it in.

It's making that same sizzley sound. And, if you can't hear it, you can at least see that there's more fog that comes out. Because, again, when it makes a gas, it's gotta go somewhere, so it spills out of the container.

Carefully take it out please.

Same deal. You stand over here. I'll hold it. And you squeeze.

Flower: -crunch-

Audience: Wow...

Audience: Poor flower!

Steve: Yeah... You hold this.

Now then, what happened to the flowers.

Audience: They froze.

Steve: Why'd they break?

Audience: They froze.

Steve: What froze?

Audience: The flower!

Steve: What in the flower?

Audience: The atoms.

Steve: What in the petals?

Audience: The water.

Steve: The water! There's a lot of water inside the flower. The flower's like 70, 80 percent water. They shoved the flower in there, all the water froze, turned to ice and when they squeezed it, instead of being a liquid and being able to flex, it was a solid and it broke. Do our brave volunteers have any water in them?

Audience: Yes.

Steve: Yeah, your body's mostly made out of water. What would happen if they were to shove their hand in here?

Audience: Same thing!

Steve: Yeah, same thing! All of the water, all of the blood in their hand would freeze and if they took their frozen hand and kinda whacked it on the table? You'd have little bits of hand on the table! So, should they put their hands in?

Audience: Nooo!

Steve: No, they shouldn't! But give them a hand for helping us out! Give them a big hand!

You can take off the goggles and gloves.

I'll put these over here so that nobody notices that they're hurt.

I'm going to need two more! Two more brave, and slightly foolish...

Oh, dear...

No one ever wants to...

The lady with the blue Jefferson Lab bag... And, and, the lady in the white sweater.

Oh, go the other way, my dear. It's much shorter this way.

Goggles and gloves!

And... She's almost out. Almost.

Should have just thrown her over.

Urrgah!

Perfect! Goggles and gloves!

Oh, dear.

Tell you what...

Okay, put these on your face.

Okay.

And... That goes on that hand.

And while they are getting goggled and gloved... What, are these?

Audience: Balloons!

Steve: Balloons! Filled with?

Audience: Air.

Steve: Air. Just air. If they were helium, go really high, be hard to use. What are we going to do with these?

Audience: Put them in the nitrogen!

Steve: Stick them in the nitrogen! What's going to happen?

Audience: Pop.

Steve: They're going to pop, of course.

Which one do you like?

Which one do you like?

Good choice.

Tell you what, you stand right over here. And you stand right over here.

Hold the balloon by one end. And, at the count of three, you're both going to put the balloons into the nitrogen at the same time, but not your hands.

I'm going to stand way back here.

So, give us a count!

Audience: One! Two! Three!

Steve: Put them in!

Have they popped?

Audience: Nooo...

Steve: Keep pushing!

Audience: They're frozen.

Booo...

Steve: Keep pushing.

What's happening?

Audience: The air's leaking out.

Steve: That's not good...

Audience: Nooooooooo....

Steve: Not good...

Tell you what, you let go of this one. And you let go of that one.

That's not good!

Do the balloons have any air in them?

Audience: Noooo.

Steve: Well, the choices are either 'yes' or 'no,' right?

Maybe, maybe instead of popping maybe the balloon just got really cold and it cracked lie an egg. And then all the air leaked out through the crack.

If it's true that the balloon has a hole in it and the air is gone and we take the balloons out, what will they do?

Audience: Shatter. Blow back up.

Steve: It's a balloon with a hole in it. It's going to stay the same.

Who says the air is in there? If the air is in there, where is it?

Audience: Frozen!

Steve: Okay, so if we take it out and let it get warm, what will happen?

Audience: Blow back up!

Steve: Two different theories, two different predictions. What should we do?

Audience: Take it out!

Steve: Gotta try it out!

Grab your balloons. Hold them up high so we can all see, please.

Shake them around. Do a little balloon dance.

Audience: Random excited chatter.

Steve: Now... Let me see this one, please.

Are the balloons okay?

Audience: Yes!

Steve: Do they have holes in them?

Audience: No!

Steve: Did the air leak out and then go back in?

Audience: No...

Steve: So what's going on here?

Tell you what. This is the Open House. We're not going to demonstrate it with those little wimpy balloons.

Audience: Whooa!!!

Steve: I'm going to put this in.

If I put this in here, what's happening to the temperature of the air in the balloon?

Audience: It's freezing!

Steve: It's getting colder. What did we say earlier happens to the particles of a gas when they get cold?

Audience: It goes slower.

Steve: It slows down, they take up less space and, if you get them cold enough, you can change them from a gas to a...?

Audience: Liquid!

Steve: And I claim that's what we're doing. I claim we're getting this cold enough we're taking all the air, all the oxygen and all the nitrogen, and we're changing it from a gas to a liquid. If that's true, what should we see in the bottom of the balloon?

Audience: Water.

Steve: We should see a liquid.

It's going to be hard to see, so I'm going to kill the lights part way. And I'm going to hit it with a flashlight.

Audience: Oh, wow!

Steve: At the very bottom of the balloon.

Audience: It's liquid! It's liquid!

Steve: What is that little puddle in the bottom of the balloon?

Audience: Liquid air!

Steve: That's air. That's a little puddle of liquid oxygen and a little puddle of liquid nitrogen. If I shake it, you can even hear it.

Liquid Air: Slosh, slosh, slosh.

Steve: And if I keep shaking it, it goes away, right, because it all boils again and changes back to a gas.

So, party tip. The next time you have a party with a lot of balloons, at the end of the party, don't throw the balloons away. Just get some liquid nitrogen. And you can shove the balloons in. And all the air inside the balloons will change from a gas to a liquid. And the next time you want to have a party, instead of blowing-up a bunch of new balloons, you take the old ones out. Put them somewhere hot, like the table. And then the liquid air inside will boil.

Sometimes they pop so be aware.

And, if all goes well...

Audience: Ooooh!

Steve: The balloons survive...

Balloon: Pop!

Audience: Aaah!

Steve: Sometimes they pop.

And you can have another party!

Let's have a hand, please, for our brave volunteers!

I'm going to do the same experiment they did, but backwards. Instead of taking air, trapping it and getting it cold, I'm going to take the liquid, I'm going to put it in these little film canisters, and I'm going to trap it, and I'm going to let it get hot. And once these are cold, we'll snap the lids in place...

Whoops...

Uh-oh...

Get on...

What's going to...

Film Canister: Pop!

Audience: Whoaaa!!!

Steve: What's going to happen!

Film Canister: Pop!

Steve: Why'd they pop?

Audience: Pressure!

Steve: Where's the pressure coming from?

Film Canister: Pop!

Audience: Whoaaaa!

Steve: If you remember the balloon...

All of this air. All this air was a little puddle of liquid in the bottom of the balloon. If I put a little puddle of liquid in the container, it's going to try to make a balloon's worth of air. It can't fit. Sooner or later, the pressure goes too high and the lids pop off.

Also remember that as soon as I put the lids on, nothing new goes in. Same amount of stuff.

Film Canister: Pop!

Steve: But some of it is changing to a gas. It's able to hit the lid. And the stuff that is hitting the lid is moving faster and faster because it's getting hotter. So, sooner or later, there's so much stuff hitting the lids that the pressure goes too high and the lids pop off.

Film Canister: Pop!

Steve: Now, remember my big tank. My big tank has a lid.

Audience: Ooooh!

Steve: If I do this... And then I do this... What's going to happen?

Audience: Nothing!

Steve: Why nothing?

Audience: It's vented.

Steve: Yeah, this is more like a hat. This isn't really sealed on.

That's on purpose. Right, you don't want, you don't want the gas building up in here. A little film canister going 'pop' is kind of cute. A real thing like this going 'pop' is going to go through the ceiling. Which... They yell at you when you do that kind of thing.

So! What is this?

Audience: Rocket!

Steve: Yeah, it looks like a rocket.

Steve: This is actually a magnet. And it's a little bit of a weird magnet because it plugs directly into the outlet. And I don't know if you know this or not, but the electricity you get from the outlet changes directions 60 times a second. So, when the electricity is flowing this way through the magnet, this becomes the north pole.When it flows this way through the magnet, this becomes the south pole. So north and south on this thing are flipping back and forth 60 times a second.

What's this?

It's actually a copper ring.

Does copper stick to a magnet?

Audience: Yes.

Steve: No. If I turn it on, it doesn't stick. But if I place it on, it floats.

Audience: Whoa!

Steve: If I turn it off, it falls.

If I turn it on real fast, it flies off into the air.

That's because the magnetic field made in this ring... from the changing magnetic field here... The changing magnetic field makes electricity run around this ring. This becomes an electromagnet. And the way that the math works out, whatever pole that is, that's the same. So it's always sitting here up in the air.

But it doesn't really go all that high.

That's because the ring has a fair amount of resistance. Which means the electricity that's flowing through the ring can't flow as well as it could. I can fix that... using a tiny bit of nitrogen.

Audience: Uh-oh!

Steve: We'll put a little bit here.

Resistance acts like friction for electricity. And, sometimes it's good. Right, you use it to change electrical energy into heat. That's why you toaster works. But a lot of times, it's bad. It's just wasted energy. But, if you get a conductor cold, you can lower the resistance. And, if you lower the resistance, the electricity will flow better. If the electricity flows better, how will it jump?

Audience: Higher.

Steve: It should jump higher.

Now, some materials, get them cold enough, they lose all their resistance. Those are called superconductors. That's what we have inside our accelerator. We use liquid helium to make these things called niobium cavities, which you'll learn about when you go out there, we make them superconductive. Mostly, so that we don't generate waste heat. And, in part, that actually saves us quite a bit of money. Right now, we pay about a million dollars a month in our electrical bill. If we had regular things that make heat, our electrical bill would be about ten million dollars a month. So, just by using superconductors we can save about nine million dollars a month in our electrical bills.

Now, this is not a superconductor. But, it's a better conductor now. We're expecting it to go higher into the air.

Front row!

I don't always catch these things. If the ring comes towards you, don't grab it. If you grab this thing when it's cold, frostbite in about half a second.

Remember how high it went before? See if it's any better now that we've lowered the resistance.

Not too bad.

And it we turn it on at the right time, you can actually hit the ceiling.

Ring: Whack!

Audience: Whoa!

Steve: It's not a superconductor. There's still some resistance.

If have some frost on the ring, and I hold the ring in place, the heat made from the electricity brings us above the freezing point and the frost just vanishes off the ring. And I can hold it and not get frostbit, which is nice.

Now...

Who is ready for a quiz?

Who is not ready for a quiz?

Best time for a quiz, when you're not ready for it.

It's not a hard quiz, so don't panic unless you like to panic. It's not that helpful.

Question number one, what is this?

Audience: A ball.

Steve: What kind of ball?

Audience: Ping-pong.

Steve: Ping-pong ball. And this is how a ping-pong ball bounces.

Ping-pong Ball: Bounce. Bounce.

Steve: It's insanely exciting.

What's this?

Audience: It's a ball.

Bouncy Ball: Bounce.

Steve: Bouncy ball.

Bouncy Ball: Bounce.

Steve: That's how the bouncy ball bounces.

Uh, oh. Come back.

What's this?

Audience: Bouncy ball!

Steve: Racquetball.

Racquetball: Bounce.

Racquetball: Bounce.

Steve: That's how the racquet ball bounces.

All of this insanely exciting!

We'll let those get cold.

While that's getting cold, what's this?

Audience: A cup!

Steve: This is called a Jefferson cup.

It's not made out of little bits of Jefferson, which would be gross. It's made from a metal called pewter.

Pewter is a soft metal. Soft in that, if I squeeze it, I can change the shape fairly easily.

Okay. Now, since this is so nice and soft, it makes a beautiful sounding bell.

Jefferson Cup: -clank-

Steve: Doesn't it?

Jefferson Cup: -clank-

Audience: Nooo.

Steve: Not really. But, you know, it's all smooshed.

There's another one here that's not smooshed. And, this one's slightly shiney! This one makes a beautiful sounding bell.

Jefferson Cup: -clank-

Steve: Doesn't it?

Jefferson Cup: -clank-

Audience: No.

Steve: Not really.

How can I make these ring better?

Audience: Put it in the liquid nitrogen!

Steve: Sure! I can get nitrogen into these cups either the easy way or the hard way. Which would you prefer?

Audience: Easy way! The hard way!

Steve: I heard someone say 'easy way'! No one every picks easy!

Either way, it's the same way. So, you don't actually have a choice.

So a little bit there, a little bit there... A little tiny bit on the table.

Now, then. While these get cold... Let's see how these guys are doing.

Which ball?

Audience: Ping-pong ball!

Steve: 321 degrees below zero, going to bounce it on the metal plate.

What's it going to do?

Audience: Break!

Steve: It's going to break, of course.

Audience: Bounce it!

Steve: Ready?

Ping-pong Ball: Bounce.

Ping-pong Ball: Bounce.

Steve: Actually, kind of a boring experiment. Nothing really happens. But nice to know some things can get really cold and they don't care.

If you're going to build a machine like we did that has to run when it's cold, you need to know which materials are good and which aren't. Turns out ping-pong ball, really not all that bad.

Question number two.

What ball's this?

Audience: Bouncy ball!

Steve: 321 degrees below zero, going to bounce it on the metal plate.

What's it going to do?

Audience: Break!

Steve: Break! Of course!

Ready?

Bouncy Ball: Whack!

Audience: Whoa!

Bouncy Ball: Whack!

Steve: Yeah...

Bouncy Ball: Whack!

Steve: Not a very good bouncy ball.

Bouncy Ball: Thud! Thud! Thud!

Bouncy Ball: Ding! Ding!

Steve: Hard as a rock. Maybe not a bad marble now, but not a very good bouncy ball.

Question three.

What ball is this?

Audience: Racquetball!

Steve: 321 degrees below zero, going to bounce it on the metal plate.

What's it going to do?

Audience: Break!

Steve: Y'all said break for everything! Something got to break, right?

Ready?

Racquetball: Shatter!

Audience: Oh!

Audience: It broke!

Steve: That, uh... That kind of broke.

So, the lesson to take from this. If you ever go on vacation somewhere where it's really, really cold, somewhere like Pluto, okay? Go ahead, bring ping-pong balls. You can play ping-pong on Pluto, not a big problem. Go ahead, bring the bouncy balls. Use them as marbles or small rocks or something. And if you ever want to play a game of racquetball on Pluto, make sure you serve first! That's it...

Now, then. The bells.

What did this first one sound like when it was warm?

Audience: Thud.

Steve: Yeah, kind of a thud. Let's see if it's any better now that it's cold.

Jefferson Cup: Ding... Ding... Ding... Ding...

Steve: It's better. It's not great. It's still smooshed. It's still not shiny.

This one. Not smooshed, shiny!

Jefferson Cup: Ringgg! Ringgg! Ringgg!

Audience: I like that!

Steve: Not too bad!

We took the pewter inside the cup, froze it rock hard. Hard things ring better than soft things do. That's why your pillow doesn't ring at night when you put your head against it.

The little bells also signal the end of our little show here but it's not the end of the day.

There's lots more Open House to do! Go to the tunnel, go to the end stations. There are other places in here. You have a Computer Center tour. Other stuff in this building.

Thank y'all for coming to Jefferson Lab. And I hope you enjoy yourselves while you're here!

This presentation took place as part of Jefferson Lab's 2010 Open House. Visit this page for information about our next Open House!

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