SCIFUN2001HD Science is Fun: Hot and Cold Transcript  

§[energetic instrumental music]§  

[chemical zips]
  
[drumroll]
 
§[Science is Fun Band plays a regal fanfare]§
  
[cheers and applause]
  
[blasts fire extinguisher]
 
[fire extinguisher hisses]
  
[cheers and applause]

- Bassam Shakhashiri: Hello, everyone, and welcome to my lab. I'm so happy to see you on this very special anniversary program, the 50th annual Once Upon a Christmas Cheery in the Lab of Shakhashiri. 
[cheers and applause]

Thank you! It's a very special event and I'm thankful to the Science Is Fun Band, under the direction of Professor Mike Leckrone. 
[cheers and applause]

I'm also thankful to PBS Wisconsin. We have had a partnership for five decades where they bring this program to people all around the state of Wisconsin, indeed, all over PBS stations around the country. 

So, thank you again for being part of this very special event where we will do science experiments. Together, we will explore and learn and think about what you experience. 

In my lab, we always obey the safety rules. You notice, already I have my goggles on and I have this fire extinguisher. It's not a toy. It's part of the safety procedures that we have. And I'm going to set it right here so you and I know where it is, just in case it's needed for something that might go out of control. We're not planning on anything going out of control. We just have it as part of the safety regulations. Safety is paramount in everything that we do. 

And in the experiments that we're doing today, we will be,  you will be, along with me, looking for color changes, explosions, liquids that glow in the dark. You just be on the lookout! So, sit back and relax, and if you pay attention, you're going to learn quite a bit of science and you're going to be having, I hope, an enjoyable experience. 

So, are you ready to learn? 
[audience cheering]

- Yeah!

- Are you ready to have some fun? 
[applause]

Well, let's get started then. And I'm going to turn this on, and 'Oh!' 
[audience oohs]

That got your attention. 
[laughter]

This is an example of what we call a controlled combustion reaction. The gas propane is burning and gives us this nice beautiful flame. You can see the yellow color at the top. And down at the bottom, if you're close enough, you can see a blue tinge through the flame. There it is. Very beautiful blue tinge that we have. And this is controlled combustion, just like the reaction of a flame in the candle, and I'm gonna try to lower it down a little bit here, like so. 

Now, when you came in, you noticed that we have a lot of equipment and material, not only on the tabletops, but we have some things up in the air. What do we have up in the air?

- Audience: Balloons!

- And how many balloons are there?

- Audience: Six!

- Are they all the same color?

- No!

- Well, maybe that is a hint, for me and for you, to pay attention. Because I'm going to tell you that these balloons, as you already know, have gases in them that are lighter than air. That's why they're up in the air. And what I'm going to do is take this flame and set off, if I can reach it-- Yes, I'll be able to reach it. I'm going to set off the flame to this balloon, and we'll see what happens. You ready for this?

- Yeah!

- Some of you are covering your ears. Why are you covering your ears? 
[audience laughs]

Because you know from experience that there might be a loud sound here. So, here we go. Let's try it and see what happens. 
[balloon pops]
[audience screeches in surprise]

 Well, that balloon had in it the gas helium, and helium does not burn. What we always do in science is repeat the experiment. So, let's go over to the same colored balloon. I like the smile on your face. And, you ready for this? Let's see what happens now. 
[balloon pops]
[shrieks of startled delight]

 Did the same thing happen?

- Yes!

- Exactly the same thing?

- No!

- No, in the second balloon, the flame went out. Maybe you're thinking about, why did the flame go out? The balloon had in it the gas helium. Maybe the flame went out because I brought it too close to the balloon? You think about what you see and what you hear, and try to make some sense out of it so that you can enjoy, as much as possible, explorations that we go through here. Well, I have a couple of other balloons right here. And let's see what happens when I put the flame to this balloon here. Are you ready for this?

- Yes.

- You sure you're ready now?

- Yes!

- Here we go! 
[loud boom]
[audience squawks]

 Did that balloon have helium in it?

- Audience: No!

- That balloon had in it the gas hydrogen. And hydrogen combines with oxygen from the air in what we call an uncontrolled combustion reaction. You know what's another name for uncontrolled combustion reaction?

- Audience: Explosion.

- Shakhashiri: Explosions, yes. And what do we always do in science?

- Repeat the experiment.

- Bassam: Repeat the experiment. So, let's repeat the experiment, but this time, let's do it in the dark. And see if we can learn some more as we bring this here. Ready for this? Here we go. 
[loud boom]
[audience screams]

 Did you see that ball of fire?

- Yeah!

- And did you hear a louder explosion than the popping of the helium-filled balloon? Let's have a look at this last experiment in slow motion. So, watch the monitor. You see the flame coming close. You won't hear a sound right now. And there is that big ball of fire. So, when we look at things in slow motion, we learn a few more facts and we can think about what we've learned. All right, so we've got lots of experiments lined up here, but we still have two balloons over there. Shall I do experiments over here or do more balloons?

- Balloons!

- More balloons? Okay, let's move over to more balloons. And, when we do these experiments and we make sense out of them, we pay attention. You paid attention and you noticed that the hydrogen-filled balloons gave us a louder sound than the helium-filled balloons. So, maybe these will give us even a louder sound? And that's why I want everyone to protect your ears from potential damage by taking both fingers and you stick 'em in your ear very tightly. I cannot do that and do the experiment at the same time. That's why I have ear protection like this. Now, if you can hear the sound of my voice that means you don't have your ears well-protected. All right, I saw your smile! That means you don't have your ears well-protected. Please protect your ears very well, as we go now to this balloon right here. You ready for this?

- Yeah. 
[loud boom]
[audience yelps]
[audience laughs]
[audience claps and some holler, "Whoo!"]

- Another uncontrolled combustion reaction. And that is louder because the balloon had in it a mixture of hydrogen and oxygen, and gave us a louder report. What do we always do in science?

- Audience responds in unison: Repeat the experiment!

- Repeat, also, the safety precautions as we go to this one and try to do it in the dark. If we have the lights down.  You ready for this? Ready?

- Yep.

- Yeah! 
[loud boom]

[audience howls]

[cheers and applause] 

- Let's have a look in slow motion. Again, you won't hear the sound, but you'll see a much faster reaction because there is more oxygen on the inside. The ball of fire did not last as long, and, of course, you heard, even with your ear protection, a much louder report. Well, before I go on with the next set of experiments, I need some help in cleaning up the mess that I just made here. So, could someone please come out and give me a hand in cleaning this up? 
§["The Parade of the Wooden Soldiers" by Leon Jessel]§

§ §  
[applause]

Now, don't you wish you have helpers like that in your lab? 
[audience laughs]

In my next experiment, I'm going to use a very cold liquid. It's called liquid nitrogen. It's kept in a special container, which is really just a big thermos bottle. And I have some of it also right here in this container. I'm gonna show you. I'm gonna just spill some on the tabletop here.  And this is a good way to dust off the tabletop. 
[laughter]

This liquid boils at -196 degrees Celsius. It's really, really very cold liquid. Then what I'm going to do is take some gas out of this green cylinder. This green cylinder has in it oxygen gas, and I'm going to pass the oxygen through this copper coil that is immersed in the liquid nitrogen. I do this, and turn the valve on a little bit, like so, so the gas flows out, and you see this Tygon tubing is a little, is quite a bit loose. That's what you expect it to be. And pretty soon we'll see if anything else happens to it. I can see for sure, we're gonna need more liquid nitrogen because when I put the copper coil in there, it is warmer than -196 degrees Celsius, and it's going to warm up the liquid.  So, let's see what happens. Let's see, is anything coming out of here?

- No.

- Huh?  I need some to come out. Now, yeah, something is coming out. And you can see that this flexible tube is a little stiff now. So I'm going to collect there, it's stiff by itself. I'm going to collect what's coming out right in here. 
[gas gurgling]

And if you look closely, you'll see there's a liquid at the bottom of the test tube, and this liquid has its own characteristic color. This is liquid oxygen. Liquid oxygen is being collected there, and it is condensing in the liquid nitrogen. The temperature, the boiling point of liquid nitrogen is -196 degrees Celsius. So I'm filling up this other flask here with liquid nitrogen. 'Cause I want you to see how it bubbles, like so. It keeps bubbling until it cools down the Dewar. 

And now, we've got quite a bit of liquid oxygen there. So, I'm gonna take this out. Take it out. Put this here to keep it cold, and collect some more. So, I'll let it collect some more like this because the next experiment I'm doing is using this magnet. This is a very strong magnet. I'm gonna take this metallic object and put it between the poles of the magnet, and you can see I have to pull it, I really have to pull it out. Now let's do this part here. It's really stuck to it, a very strong magnet. So what I'm going to do is take some liquid nitrogen and pour it between the poles of the magnet, and, of course, the liquid passes through. Most liquids that we know about, maybe all liquids you know about are not magnetic. So a little more liquid nitrogen right there, and then, I take the liquid oxygen, and I pour it between the poles of the magnet.  
[audience exclaims]

And the liquid is held between the poles of the magnet! Have you seen a liquid held between the poles of a magnet before?

- No.

- This is one of the properties of liquid oxygen. It is paramagnetic. Let's do it again, here it is. There it goes. 
[audience oohing]

 And it stays there until it evaporates. So, you like this experiment?

- Audience: Yeah! 
[audience applauding]

- All right. I lost some of the liquid oxygen that I needed, but that's okay. I'm gonna close this off, put this here, I have more liquid nitrogen right there. And I'm going to do another experiment in this beaker right here. It's empty except for air. And what I'm going to do, I may cool this off here a little bit, yeah. Keep 'em cold. So as you thinking with me about this experiment, liquid nitrogen boils at -196 degrees.  We were able to condense liquid oxygen in the liquid nitrogen. So is the boiling point of liquid oxygen higher or lower than that of liquid nitrogen? Do not let the minus sign confuse you. Think about that as I now reach and I wanna light a cigarette, but I'm gonna light it this way. I don't wanna light it any other way.  Is this lit?

- No.

- Yeah, it's smoking. I'm going to put the cigarette right in here and then I'm gonna take whatever liquid oxygen I have in both of these and dump it in there. 
[audience oohing]

And now you see the complete combustion of the cigarette. And this is what we should do with all cigarettes. 
[audience laughs and applauds]

  And now, I have another experiment that I'm going to do with... What does this look like?

- A ball.

- Yeah, what color is it?

- Blue.

- Hey, do I have to ask all the questions all the time? 
[audience laughs]

 I know you're thinking them, but we all have to develop the skills of sharing what you have. So here is this nice blue racquetball. It's pretty bouncy, as you would expect it to be because we know from experience what these balls do. So, what I'm gonna do is put this rubber ball in the liquid nitrogen like this. I'm gonna move it over here, and I need more liquid nitrogen. Do I have any more liquid nitrogen? Yeah, I have liquid nitrogen. How much do I have in here? I don't know, we're gonna find out. There it is. And you see it's boiling, the liquid is boiling. Why is the liquid boiling? Because the ball is warmer than -196 degrees Celsius. Did you get that point? Yeah, I know you got that point. All right, you're thinking about it. 

So what I want to do is cool this off, stay down there, stay down here. Another interesting thing about the ball, it floats in liquid nitrogen. So that's something else to think about. How come it doesn't sink in there? It floats in there, so stay in there because what I want to do next is fill up my big Dewar with more liquid nitrogen. There we go.  

What is this white stuff that's coming off the side? You're thinking about that, right? You're wondering what it is, right? You know what it is. It's called... It's cold nitrogen gas, and hitting the environment where there is moisture in the environment, so a little bit of condensed water vapor. So more over here. All right. So, let that cook a little more. A little more. 

Why is it boiling now? Because the tongs are metallic and they're warmer than -197 degrees Celsius. So, I've got this balloon in here, and you can tell it has a gas in it lighter than air. You're covering your ears again? 
[audience laughing]

Maybe you need to do that, maybe you don't. So let me show you what happens when I take liquid nitrogen and I put it on top of the balloon here to cool off the gas that's inside. 
§[trombones play warbling "Wah, Wah, Wah" fail music as balloon crinkles]§

Sounds like the balloon is hurting. 
[audience laughing]

And then, we wait for it to warm up. As it warms up, the gas atoms, the helium atoms that are in there are going to move faster, move faster. And then, there is the balloon going up. 
§[ascending climactic music]§

Up. 
[audience applauding]

Up, up. All right, well. There's one other item that I would like to work with, with you. And as to reach back here and get one of those very pretty chrysanthemums.  Isn't that pretty? 
[boiling liquid nitrogen hisses]

Beautiful color. 
[boiling liquid nitrogen bubbles]

Where are you going? 
[laughter]

What I'm going to do is take this very beautiful flower and put it in liquid nitrogen.  And add more liquid nitrogen. What do you think is gonna happen? Anything? 
[audience murmuring]

It's gonna get cold. I know it's gonna get cold, really cold. But what else? 
[audience murmurs indistinctly]

You think it'll stay pretty?

- Audience: No.

- Let's find out. It still looks pretty, right? But something has happened to it. It has become [petals clinking] very fragile. 
[audience oohing]

Very fragile, so all right. Now, I go back to the rubber ball, and a rubber ball is still there. I think I should put my gloves on, right? To protect my hands from frostbite, because what I'm going to do is use the tongs to get the rubber ball out. So come on, come on out, hello. Come on out.  There it is, I've got it. And when I walk over here and let's see now how bouncy this ball is. You ready for this? Here we go. 
[cymbals crashing]
[audience applauding]

That was a shattering experience, wasn't it? 
§[Science Is Fun Band plays triumphant music]§

My next experiment is with plastic bottles. I have three plastic bottles of different sizes. There's one, there's another one, and here's the third one. And, of course, you see that I have a fourth one, but the fourth one shows the inside of how these screws are put in. They are not touching on the inside. 

So, this cutaway is to show you that they're not touching. And each bottle has a small amount of a clear and colorless liquid in it, but also each bottle has a cork on top. 

Let me show you what I'm going to do here. I'm going to take this source of a spark. It's called a Tesla coil. I'm going to hold this metallic spatula very, very tight and push the button, and now you can see a spark. 
[Tesla coil's current buzzing]

There you can see the spark, right? Now, I'm going to touch this screw and show you the spark is jumping across the gap that separates the two screws. All right, in the first bottle that I have over here, I'm going to touch one screw and see what happens. You ready for this?

- Yeah!

- You sure you're ready? Here we go. 
[current buzzes, cork pops, audience shrieks]

 Were you ready? Are you ready for the next one?

- Yeah! 
[electricity sizzles, cork pops, audience yelps]

- Here we go. And how about this one? 
[electricity thrums, cork pops]
 
[audience yelps, laughs]
  
[audience laughing, "Whoa!"]

Are you ready for this one?

- Audience: Yeah!

- Here we go. 
[electron arc crackles, cork pops]
[audience yelps, oohs]
[audience laughing]

You ready?

- Yeah!

- One, two.

- Three! 
[electricity sizzles, cork pops, audience yelps]
[audience applauding]

- I'm glad you liked that experiment. I like that experiment, too. You have been a wonderful audience on this very special 50th-anniversary program. I wanna thank you for coming here, I wanna thank you for your support of our program, and I, of course, wanna thank everyone who has made it possible, and especially thanking you for the eruption of your enthusiasm. 
[audience oohs]

And the outburst of your affection. 
[audience ahs]

And thank you for all your support here 
[audience cheering and clapping]
in this very special program. Thank you all very much. Thank you, thank you. 

§[slow, elegant version of "If You Want to Be a Badger"]§ 

§[sparkly piano music]§

And all of us, each one of us, we all have awesome responsibilities. Not only to ourselves but to the future generation that we love so much to protect our planet and try to mitigate climate change. And there's my daughter and my granddaughter. Thank you, Violet, and thank you, Elizabeth. 
[audience applauding]

§[band plays a jazzy tone]§

§[triumphant music]§

§["If You Want to Be a Badger"]§ 
§[audience clapping along]§
  
§[song wraps with a triumphant apex]§

[cheers and applause]
 
§[energetic instrumental music]§