00:00:00 Ladies and gentlemen, Professor Bassam Shakhashiri.

00:00:30 Boys and girls, ladies and gentlemen, welcome to the 13th annual Christmas lecture. Among

00:00:48 our guests tonight are students and faculty from the University of Wisconsin-Madison,

00:00:56 schoolchildren from the Madison area, parents and other members of the community. I am pleased

00:01:03 to have as my special guest tonight the Dean of the College of Letters and Science, Dean

00:01:09 David Cronon. This special event is aimed at people of all ages. I want youngsters and

00:01:18 adults alike to learn a few things about chemistry and about what chemists do. Chemicals

00:01:26 are all around us. The food that we eat is made up of chemicals. The air that we breathe

00:01:33 is a mixture of chemicals. Our own bodies are made up of chemicals. The medicine and

00:01:40 drugs that we use when we are sick are nothing but chemicals. And so chemicals are all around

00:01:46 us. Chemists do experiments in order to understand the behavior of chemicals. We study chemical

00:01:54 reactions so that we learn how to control them and how to put them to good use. All

00:02:02 chemicals are safe to handle if we obey the safety regulations. Safety regulations call

00:02:09 for us to wear eye protection whenever we do experiments, and that's why I'll be wearing

00:02:15 these safety goggles throughout the rest of this program. In addition, I have a fire

00:02:21 extinguisher available, which will be used only if needed. This fire extinguisher is

00:02:29 available, as I say, to be used only if needed. I hope we will not need it tonight. As we

00:02:35 handle chemicals, we should be fully aware of their potential hazards so we don't injure

00:02:44 ourselves, other people, or the environment that we live in. Now, doing chemistry can

00:02:51 be a lot of fun, and that's what I hope we will have tonight. I want you to sit back

00:02:56 to relax and to enjoy the festivities, and I want you to try to make as many observations

00:03:03 as possible. Look for color changes. Look for changes in volume. Watch out for explosions.

00:03:12 Think about what you see and what you hear. Be very careful in paying attention to what

00:03:20 I do and to what I say. Now, if you are ready, I'm ready. Are you ready? All right. So let's

00:03:27 begin, then, by looking at the properties of some material that are gases. Now, gases

00:03:36 are quite useful chemicals. We all know about the use of natural gas to heat our homes.

00:03:43 And so natural gas is a chemical substance called methane. As you probably know, that

00:03:49 substance is odorless, does not have an odor. But the gas company adds a chemical to it

00:03:56 in order to allow us to detect the presence of gas if there is a leak. And so natural

00:04:03 gas, which is methane, is quite odorless. We cannot smell it. The additive is what we

00:04:09 smell. And so what we will begin to do now is to work with some of the natural gas. And

00:04:16 I have this big wand over here, which is actually a big torch. And you'll see that when I light

00:04:23 it, there it is. There is natural gas burning. This chemical reaction that we're witnessing

00:04:30 here is called combustion. Combustion is nothing but a reaction of a substance with

00:04:36 air. Now, combustion reactions are all exothermic reactions, which means that they release energy

00:04:44 to the environment. This release of energy is what makes it possible for us to heat our

00:04:50 homes, to heat this building, to heat this room that we're in now. Now, some gases undergo

00:04:56 controlled combustion reactions. This is an example of a controlled combustion reaction.

00:05:02 Other gases undergo very rapid combustion. In other words, they go out of control. And

00:05:08 those reactions we call explosions. And that's what we're going to see now as we look at

00:05:14 these balloons that we have around us. Now, these balloons clearly contain gases that

00:05:21 are lighter than air. That's why they're held up in the air and held to the table by

00:05:26 these strings, which you may not be able to see. But you can see that the balloons are

00:05:30 not all the way up to the ceiling. So we will begin by trying to set these balloons on fire

00:05:41 to find out if these balloons contain gases that undergo combustion. So we'll start off

00:05:47 with this blue balloon over here. We'll look at this balloon. It's lighter than air, as

00:05:51 we said before. We put the torch to it. I notice some of you are covering your ears.

00:05:55 Are you expecting an explosion? Well, that might be a good thing for you to do. But you

00:06:00 see, we do experiments in order to find out what's going to happen. So, are you ready

00:06:06 for the experiment? All right. We'll begin with this balloon. And you see, all that has

00:06:13 happened is that the balloon popped. And the gas that was inside the balloon, which

00:06:18 is lighter than air, did not undergo a combustion reaction. Now, the balloon that I have over

00:06:25 here, this pink balloon, this balloon contains methane. And methane is natural gas. And so

00:06:34 what we want to look at now is what happens when the combustion of methane is not controlled.

00:06:41 In this burner here, it's undergoing controlled combustion. But we'll watch here and see what

00:06:46 happens. So you pay close attention. We'll see what happens here. And you see, there

00:06:53 was a very big flame. And that's why it's very dangerous if you have a gas leak at home.

00:06:59 It's very dangerous for you to start anything, strike a match, or spark anything. It's extremely

00:07:06 dangerous. So methane, we know, undergoes combustion and can be controlled, also can

00:07:10 go out of control. Now, let's move on and look at this yellow balloon over here. This

00:07:17 yellow balloon has a gas lighter than air. And we'll try to put the torch to it and see

00:07:24 what happens. So are you ready? All right. And you have your ears covered? Okay. Now,

00:07:33 this gas that we just exploded there is hydrogen gas. Hydrogen gas undergoes combustion very

00:07:40 rapidly. Now, there was a big flame. And what I would like to do now is to show you

00:07:45 this flame in slow motion. So let's look at a replay of this experiment and look very

00:07:51 carefully at the flame as it explodes in the mixture of hydrogen. So if you'll look with

00:07:58 me now, watch. You'll see the reaction in slow motion now. Watch the big flame. And

00:08:06 there we go. That was the same flame we just saw here, except we're showing it to you in

00:08:15 slow motion. So we've learned so far. You like that? All right. What we've learned so

00:08:24 far, I hope, is that methane undergoes rapid combustion and hydrogen undergoes rapid combustion

00:08:32 and therefore, we should keep flames away from those gases. Now, this red balloon that

00:08:36 we have here, we shouldn't let it just sit there by itself, should we? This balloon,

00:08:41 I will tell you now, this balloon has a mixture of hydrogen gas and oxygen gas in it. And

00:08:50 this mixture is very highly explosive. And this mixture, because it is highly explosive,

00:08:58 it will not only generate a big flame, but will also generate a lot of sound energy.

00:09:06 As such, I would like you to cover your ears. All right? So here we go. Are you ready for

00:09:14 this? Now, this example of hydrogen gas, this is

00:09:27 a combustion reaction between a mixture of hydrogen and oxygen, also produced a flame

00:09:34 and a lot of sound energy, more sound energy than the combustion of hydrogen. What we should

00:09:38 do now is try to look at, again, the slow motion of this explosion to see if we can

00:09:47 tell the difference between the combustion of the hydrogen and the combustion of the

00:09:53 mixture of hydrogen and oxygen. So let's look at this again. And watch very carefully.

00:10:00 Here we go. Watch it. There comes the flame to it, very slowly. And boom, there you see

00:10:11 there's the loudness of the explosion. You can't hear, but you can, but of course,

00:10:23 you saw that the flame had a lot of different colors to it. So let's move on to something

00:10:30 else now and look at some other properties. We'll turn off this source of natural gas

00:10:35 here. And that leaves one balloon here. This balloon actually that had the gas that did

00:10:41 not burn, this balloon contains the gas helium. And you all know that helium balloons are

00:10:45 used for a variety of purposes, including doing experiments of the type that we're

00:10:50 doing here. Now I want to show you a different property of helium. Now you know when we

00:10:56 talk, our vocal cords vibrate. And they send a great deal of sound energy. Now what we

00:11:04 vibrate, when the vocal cords vibrate, the gas molecules are pushed and the sound energy

00:11:10 is created so that the ear then picks it up. So the identity of the gas in which the sound

00:11:16 energy travels makes a difference in terms of the pitch of the sound. And so what I have

00:11:21 here is a cylinder that has in it gaseous helium. And I'm going to do an experiment.

00:11:28 And you watch very carefully, and also listen carefully, so you don't miss out on what's

00:11:33 going on. So you see the helium is coming out. And this is an experiment where I'm going

00:11:37 to substitute the air molecules in my throat with helium. Okay, so you watch very carefully

00:11:45 now and listen carefully. My name is Bassam Shakashiri. And you see, you see, hello, can

00:11:58 you hear me? Can you hear me? You see that the change in pitch took place because we've

00:12:03 changed, am I back to normal now? Can't tell, you tell me. The change in pitch is due to

00:12:11 the fact that we have replaced the air molecules by the lighter molecules of helium. And that's

00:12:18 why the change in pitch took place. Now, we'll take this balloon and do a couple of other

00:12:25 experiments with it. And I want you to watch very carefully as I do this experiment. We'll

00:12:31 do this experiment over here. And what we will do is take a very cold substance, which

00:12:38 we'll talk about shortly. This cold substance is a liquid. It's liquid nitrogen. And what

00:12:43 we'll do is add the liquid nitrogen to the balloon. And you see, because of the cold

00:12:48 temperature, the balloon collapses. And the balloon collapses because the helium inside

00:12:55 the balloon has been slowed down. And the pressure changed because of the change in

00:13:00 the temperature. Now, as the helium balloon warms up, of course it increases in size again.

00:13:08 And if you watch this carefully, you see that the balloon goes all the way up to the ceiling

00:13:18 because I've taken it off. Now I've taken the thread off. So, in using this liquid nitrogen

00:13:26 here that I want to talk to you about, I want to do a few other experiments with liquid

00:13:29 nitrogen. But I need to replenish my supply of liquid nitrogen. And so if one of the University

00:13:35 of Wisconsin students can help me by bringing out a replenishment of this supply, I really

00:13:40 would appreciate it. Oh, wow. Thank you very much, Bucky. Thank you. And welcome to this

00:13:48 special lecture. Thank you for bringing this over here. You see, you're very popular and

00:13:54 you're quite a big hit here. Now, Bucky, I know that you're quite busy with final exams

00:13:59 coming up and with Christmas vacation coming up. But I wonder if you can stay for the duration

00:14:06 of this lecture. Can you stay? Good, good. I know the athletic teams have been doing

00:14:11 quite well, both the men's athletic teams and the women's athletic teams, right? Right,

00:14:16 right. I know that, yeah. I know that among other things that you do, at least I heard

00:14:24 that you badger the cheerleaders. Is that right? You don't? No? No? Bucky, I'll tell

00:14:32 you what. We have a whole slew of experiments we're going to do here. And I'd like you to

00:14:36 help me out, but I see that you didn't bring your safety glasses with you and you don't

00:14:40 have any safety goggles. So I'll ask you to stick around and just watch. Is that all right?

00:14:44 I know, darn it, I know it. Let's just, let's sit around here, okay? I have a special seat

00:14:49 reserved for you over here. Okay? So we'll continue to work with, are you comfortable,

00:15:05 Bucky? Great, all right. We'll continue to work with liquid nitrogen. We've got more

00:15:13 liquid nitrogen here. And liquid nitrogen is used in a branch of science called cryogenics.

00:15:24 Cryogenics is the branch of science which deals with the study of the properties of

00:15:28 material under very cold temperatures. And so this is what we're going to do now, do

00:15:34 a variety of experiments with this liquid nitrogen. And you see, I can just pour it

00:15:37 down here. The boiling point of liquid nitrogen is minus 196 degrees Celsius. It's very, very

00:15:44 cold, and that's why we keep it in this thermos bottle, in order to prevent the liquid nitrogen

00:15:50 from evaporating. So we will do a variety of experiments with this, and these experiments

00:15:56 include working with this substance. Now, this substance that I have here in this bottle

00:16:04 is nothing but the element mercury, which is a liquid at room temperature. The element

00:16:10 mercury freezes at a temperature of minus 39 degrees Celsius. And what I have done is

00:16:16 prepared ahead of time a small item, which I will use to do the experiment. This item

00:16:24 is, using the element mercury, this item is, as you will see very shortly, a mercury hammer.

00:16:32 You see, it's quite hard. We keep it in this cold liquid here so it stays frozen, so the

00:16:40 temperature there is below 39 degrees Celsius. Now, what I have here is some examples of,

00:16:49 some samples I should say, of small pieces of rubber. And you can see that these small

00:16:54 pieces of rubber are quite flexible. And what I'm going to do is take these pieces of rubber,

00:17:02 put them in this beaker. I'll leave one out here so we can see that it is still flexible.

00:17:08 We'll take some liquid nitrogen and add the liquid nitrogen to the rubber. And we'll see

00:17:15 what happens. Clearly what happens is that the liquid nitrogen boils, because the temperature

00:17:21 of the glass beaker and of the pieces of rubber is higher than the boiling point of

00:17:27 nitrogen. That's why it's boiling off. At the same time, the glass beaker and the small

00:17:32 pieces of rubber are being cooled off. And so what I will do now is wear some hand protection

00:17:39 in order to prevent frostbite from occurring. And what we'll do is take some of these, pour

00:17:47 the liquid nitrogen over here, and then come back over here, see, pour them out. And what

00:17:57 we have is some very hard pieces of rubber, which I will use this mercury hammer to drive

00:18:07 in these rubber nails. And what we'll do is take these pieces of rubber, put them in the

00:18:16 beaker. Now remember that I had one piece of rubber that I didn't freeze, this is this

00:18:20 one, and you see I can't pound it in because it's not hard. So we'll pound out a couple

00:18:26 more. And so these pieces of rubber are actually being used now as rubber nails. Now there

00:18:37 are more serious applications for using cryogenics than the ones that I have just showed you

00:18:43 here, but I'm going to show you one other experiment which I think is of interest to

00:18:50 people at the University of Wisconsin because it has very direct practical applications.

00:18:54 But let me show you the experiment first, okay? The experiment means that I have to

00:18:59 come around, so I'll come around and show you this. This experiment involves using another

00:19:05 form of rubber in the form of this rubber ball, okay? So everybody can see the rubber

00:19:12 ball, it's quite bouncy, it has a very soft texture to it, and it has the characteristic

00:19:19 rubbery properties. So what I will do is take this rubber ball and put it in this small

00:19:27 thermos bottle and add to it some liquid nitrogen. And of course the liquid nitrogen will boil,

00:19:35 more is better, right, so let's add more. And as the rubber ball is being cooled down

00:19:49 the liquid nitrogen boils off, and if you look very carefully you begin to see the rubber

00:19:57 ball, which tells us that the rubber ball is what, denser than the liquid or lighter

00:20:04 than the liquid? It's lighter because it's floating, right? Alright, so what we'll do

00:20:09 now is try to take this rubber ball out, and I'll use these to get the rubber ball out.

00:20:17 So get the rubber ball out, it's quite cold in there. You have to be careful about this

00:20:23 and handle this very carefully. Oops. And then I ask you to watch very carefully as

00:20:31 I try to drop this on the floor. You ready? Okay, here we go. And you see the rubber ball,

00:20:38 which was quite bouncy, shattered all over the place, right? Now, I'm going to try to

00:20:43 show you, we'll see if we can show you this again in slow motion. So let's see if we can

00:20:48 see the rubber ball, which is frozen, shattering in slow motion. So we'll look for this, and

00:20:56 here we go. Watch the rubber ball being dropped, you see there it shatters into very small,

00:21:02 sometimes not so small pieces, but they're not all that small. Okay, so this experience

00:21:09 with the frozen material in the area of cryogenics has been put to a very direct application

00:21:16 by one of the professors in the Department of Mechanical Engineering. Professor Brayton

00:21:20 has developed a method for recycling old automobile tires. And so by freezing them and then crushing

00:21:28 them, then the rubber, the frozen rubber, after it warms up then can be mixed with asphalt

00:21:34 and can be used for resurfacing roads. And this has been one of the most important applications

00:21:40 in terms of recycling old tires. Now, we'll move on to more experiments in this area that

00:21:48 involves working at very low temperatures, at very cold temperatures in the liquid nitrogen

00:21:56 range. And as we try to look at some more experiments.

00:22:04 Merry Christmas! Ho ho! Merry Christmas! Ho ho! Merry Christmas! Ho ho!

00:22:34 Welcome, Santa, welcome. Hi, Doc, how are you doing? Fine, how are you? Good, good. I'm so glad that you were able to stop by.

00:22:41 Yes, yes, I was glad to see all the children here. And these children, you know, they're not afraid. A lot of children are afraid of Santa Claus.

00:22:50 This is a very common phenomenon. We call it claustrophobia in the business.

00:22:57 Anyway, I'm very happy to be here in University of Wisconsin-Madison. I'm delighted by the lovely December weather you have here.

00:23:08 It's so nice and warm. Why, up north, it's really cold up north.

00:23:15 I'll tell you how cold it is. I want to describe, we just had our homecoming football game, UW slash North Pole versus University of Greenland.

00:23:29 And I want to tell you how cold it was. The fans, you could see their breath. There was ice all over the place.

00:23:36 Men with beards were frozen. The instruments were frozen. The wind chill was minus 40 degrees.

00:23:43 Now, that's either Celsius or Fahrenheit, right? Same temperature? Okay. It was really cold.

00:23:49 Well, Santa, that does not sound to me like it's very cold because it sounds like the temperature where the Wisconsin Badgers play or the Green Bay Packers play.

00:23:58 Yes, but we play in a dome stadium. That's how cold it is.

00:24:05 Anyway, I brought you a gift, Doc.

00:24:10 You did?

00:24:11 Yes.

00:24:12 A special gift?

00:24:13 A special gift.

00:24:14 Am I going to like it?

00:24:15 You're going to love it.

00:24:16 Will I be able to use it?

00:24:17 You will be able to use it.

00:24:19 All right, I'm ready.

00:24:20 Old Santa was checking over his list, checking it twice, you know.

00:24:23 Yes, yes.

00:24:24 And he found out that you are very interested in getting some computing facilities for your education program here.

00:24:31 Yes, indeed.

00:24:32 And so I contacted my friends on the hill at UW slash administration.

00:24:42 And I asked them to let me work on the first portion of your program.

00:24:48 And they sent the money. They managed to dig the money up.

00:24:51 And I got my elves working right on it.

00:24:54 We don't call them elves anymore. We call them subordinate clauses in the business.

00:25:03 But I want to show you this is a dandy.

00:25:05 Here's your first generation computer here.

00:25:10 And you just move those little numbers along right like there.

00:25:13 And I don't know when the rest of it's coming.

00:25:15 The administration was a little shaky on that.

00:25:17 But there is more coming.

00:25:19 And there's an instruction manual if you need it, you know.

00:25:22 Even a little abacus tips workbook that you can buy with it.

00:25:25 You know, that sort of thing.

00:25:27 So that's just for you.

00:25:29 And I have a little help for the students, too.

00:25:31 There's too many of them.

00:25:32 And I'll see many of them later on when I won't see them.

00:25:35 But I'll come to visit them.

00:25:37 But I want to help them out with their final exam.

00:25:39 And I want to give them a little help.

00:25:42 A little help to remember some very important chemistry.

00:25:45 Now, all of you learned that water dissociates into protons and hydroxide ions.

00:25:54 See? Santa knows some of this.

00:25:57 Well, in our labs at UW-North Pole, we take three water molecules.

00:26:05 And we get three protons plus hole, hole, hole.

00:26:20 And I'll give you one other tip before I'm through here.

00:26:25 I was talking the other day to my cousin, Worthy.

00:26:28 And he told me why they call the periodic table the periodic table.

00:26:33 They call it that because students look at it periodically during an exam

00:26:37 to see if they can come up with the right answer.

00:26:39 That's why they call it that, believe it or not.

00:26:42 My cousin, Worthy, is an interesting fellow.

00:26:45 He's quite into the Christmas business, as the whole family is.

00:26:48 And he's a bell ringer for the Salvation Army at our new shopping center up there,

00:26:54 Ice Town Mall.

00:26:56 And he's very good at it. He's very well known.

00:27:00 And people come by and they say,

00:27:02 There's a Worthy Claus if I ever saw one.

00:27:05 That's right. It's my cousin, Worthy.

00:27:08 Santa, I know you have a lot of other lines that you want to share with us.

00:27:14 But I want to save some of the good ones for myself.

00:27:18 I know you're quite busy, but can you join our special guests tonight

00:27:22 and stay for the rest of this program?

00:27:24 Well, great. Why don't I ask you to sit over there next to Bucky?

00:27:28 Oh, great, great.

00:27:30 Hi, Bucky. How you doing?

00:27:41 Oh, I don't think I can get that.

00:27:47 Moving right along here,

00:27:50 I want to continue doing some experiments under very cold conditions.

00:27:56 And what I have done already is liquefy some gaseous oxygen.

00:28:02 We took gaseous oxygen and changed it into the liquid form.

00:28:06 And that's what I want to show you right now.

00:28:09 Here's a sample of liquid oxygen.

00:28:13 And if you look very closely at it, you'll see that it's blue in color.

00:28:18 The boiling point of liquid oxygen is minus 183 degrees Celsius, so it's quite cold.

00:28:24 And liquid oxygen has a lot of interesting properties.

00:28:28 And I want to show you some of these properties right now.

00:28:31 Now, in order to show you some of these properties,

00:28:33 I'm going to move over here where I have a very strong and powerful magnet.

00:28:39 And this magnet has, of course, two poles to it.

00:28:44 I put my penknife here. I see it's a very strong magnet.

00:28:47 Oops.

00:28:48 Hey, Doc, which pole is the North Pole?

00:28:51 Santa wants to know which one is the North Pole.

00:28:55 Well, one of them is the North Pole, and the other one is the South Pole.

00:28:58 Now, let's see what these poles...

00:29:01 Let's see what happens when we pour some liquid nitrogen

00:29:04 in between the poles of this strong magnet.

00:29:07 You see the liquid nitrogen runs right through,

00:29:10 and nothing really spectacular happens

00:29:12 except the nitrogen splashes all over the table.

00:29:14 Now, we take the blue liquid, the liquid oxygen,

00:29:18 and pour it between the poles of the magnet.

00:29:21 You see that the liquid is held between the poles of the magnet,

00:29:25 indicating that this liquid has paramagnetic properties

00:29:29 similar to the properties of the pocket knife that I used before.

00:29:33 So it's held there until it evaporates.

00:29:35 Remember, now, the liquid oxygen boils at minus 183 degrees Celsius,

00:29:40 and it's held there, as I said, until it evaporates,

00:29:43 and that's a very unusual phenomenon,

00:29:46 very unusual in the sense that, as far as I know,

00:29:50 this is the only liquid that exhibits this property.

00:29:53 Now, liquid oxygen can be used for other purposes, too,

00:29:57 and I want to do a couple of more experiments here.

00:30:00 We'll take Santa's goodies out of the way here.

00:30:04 Now, one of the experiments that I want to do with liquid oxygen

00:30:09 involves preparing a liquid oxygen cocktail.

00:30:14 Now, usually people have a cigarette

00:30:19 or some other smoking material when they drink cocktails,

00:30:28 and so I'll try this.

00:30:30 I know there's a city ordinance against smoking indoors here,

00:30:34 but this is just for the cause of science, right?

00:30:38 People actually like this?

00:30:43 Now, this cocktail, the liquid oxygen cocktail, is very, very potent.

00:30:49 It's so potent, I'm going to show you how potent it is.

00:30:52 When we take this cigarette and put it in this beaker over here,

00:30:56 you'll see that if I take the liquid oxygen and pour it,

00:31:01 you see that we have complete combustion off the cigarette.

00:31:10 And I personally think that's what we should do with all cigarettes.

00:31:16 Now, this was such a spectacular combustion process

00:31:29 that we're going to try to look at it again in slow motion, right?

00:31:34 So, let's see how the combustion of the cigarette takes place in slow motion.

00:31:40 Watch out for the flame.

00:31:42 Watch out for, there we go.

00:31:46 We pour the liquid oxygen in, and there goes the flame.

00:31:50 Very spectacular chemical reaction.

00:31:54 And it is a combustion reaction which is completely out of control.

00:32:02 All right.

00:32:03 Now, what we want to do is come back and look at,

00:32:09 let's look again at the other properties of liquid nitrogen.

00:32:16 I want to go back to liquid nitrogen.

00:32:18 And I want to take this beaker, put it over here,

00:32:21 and then take what I have here.

00:32:24 If you watch very carefully, I have an egg.

00:32:26 Can you see the egg here that I have?

00:32:28 I'm twisting around like that.

00:32:30 All right.

00:32:31 See?

00:32:32 Now, I'm going to put this egg very carefully in the liquid,

00:32:37 I'm sorry, in the beaker and add to it liquid nitrogen.

00:32:41 So, we add liquid nitrogen.

00:32:45 And, of course, the liquid boils off as we have seen all along.

00:32:48 We'll let that cool down for a while.

00:32:52 We'll come back to it.

00:32:53 Well, let's add a little bit more first.

00:32:56 We'll come back to it and do some more experiments with it.

00:33:01 I need some more liquid nitrogen,

00:33:02 so I'll come back and replenish my supply of liquid nitrogen here.

00:33:09 Oops, I've got to be more careful here.

00:33:16 And as we wait for the egg to cool down,

00:33:22 we're going to do another experiment with liquid nitrogen,

00:33:27 namely to take this flower.

00:33:31 Isn't that pretty?

00:33:33 Very pretty.

00:33:35 I'm going to put this in liquid nitrogen.

00:33:47 Now, I know that we have a lot of friends in the audience here,

00:33:50 but I have a very special friend in the audience.

00:33:54 Everybody is special, but this one is really, really special.

00:33:58 And, in fact, just earlier this month,

00:34:01 she had a very nice birthday, and she invited me to her birthday.

00:34:05 And so I'm going to ask her to come out here

00:34:09 and take a look at this flower.

00:34:12 And my friend's name is Heather.

00:34:14 Heather, you want to come out here?

00:34:16 Here's Heather.

00:34:18 You want to turn around this way so everybody can see you?

00:34:21 I'm going to take this flower and give it to you like this.

00:34:28 Now, that wasn't very nice, Heather, was it?

00:34:32 Heather, you're such a sweet girl.

00:34:34 Here's a real flower for you, all right?

00:34:36 Thank you for helping out.

00:34:45 Now, we'll come back and check our egg here.

00:34:49 And it's quite cold, so I have to try to fish it out using this.

00:34:55 And it's so cold that we'll see if it's really cooked.

00:35:00 And you see it's quite, well, it's not cooked.

00:35:10 Not quite cold, not quite cold.

00:35:16 I know some of the students are thinking this looks like the egg you have in the dorms.

00:35:26 All right, now, I want to take a closer look at the mercury hammer here,

00:35:31 which is no longer frozen.

00:35:34 You see it's being broken up?

00:35:36 It's broken up quite a bit.

00:35:38 And it is liquefying because we are not cooling it anymore.

00:35:43 So there's the handle, and the mercury is in this trough.

00:35:48 So we'll move this out and move on, because it's the Christmas season,

00:35:53 move on to a different type of experiment where we're going to trim a Christmas tree.

00:36:01 And if you look very carefully, you'll see that I have here the outline of a shape of a Christmas tree.

00:36:10 And I'm going to add to this piece of copper a colorless liquid.

00:36:23 And as we fill this large beaker with this liquid,

00:36:26 we'll see if there are chemical changes that take place.

00:36:41 You see we have the whole tree now covered,

00:36:44 and we'll look at it and see if there is any evidence of a chemical reaction that's taking place.

00:36:51 So we'll come back and look at it every now and then.

00:36:55 Now, it's been a tradition in this lecture for me to read a poem.

00:37:01 Now, this poem was written by a variety of people.

00:37:07 Some of them have contributed good lines, and some of them have contributed not so good lines.

00:37:13 I think I contributed the best lines.

00:37:17 But I'll let you be the judges.

00:37:20 This poem reads like this.

00:37:23 Once upon a Christmas dreary, in the lab of Shaka Shiri.

00:37:28 Christmas, you say, and in the lab.

00:37:32 Most would find it sad and drab.

00:37:35 But not in the lab of Shaka Shiri, where everything is bright and cheery.

00:37:41 Suddenly there was a knock.

00:37:44 Shiri stood in a state of shock.

00:37:47 You get it?

00:37:50 Good.

00:37:51 Out from the hood jumped Santa Claus, holding chemistry books in his paws.

00:37:59 Santa made me very irate when he dissolved my precipitate.

00:38:07 Then he shrieked, from my helper keep abreast.

00:38:11 She's not taking your hourly test.

00:38:14 Keep your hands off my sweet blonde.

00:38:16 I know about your covalent bond.

00:38:22 Santa, while he could, started leaving through the hood.

00:38:27 He disappeared with fan and fare.

00:38:29 And Shaka Shiri, standing there, saw an end point in the air.

00:38:34 That's the end of the poem for this year.

00:38:44 Now we're going to carry out an experiment,

00:38:47 which involves mixing a variety of chemicals together.

00:38:51 We'll move this Christmas tree just to the side a little bit so you can see better.

00:38:57 And we'll get a few things out of the way here.

00:39:01 And we'll do this experiment in this set of beakers over here.

00:39:09 So if you will watch carefully what I'm doing,

00:39:12 you will see, maybe, that there are some changes that will take place.

00:39:17 So let's go by adding some of this clear, colorless liquid.

00:39:22 We add some.

00:39:24 And we add some to this.

00:39:28 And we add some to this.

00:39:31 So far it's not too exciting.

00:39:33 Nothing is really exciting happening except that the volume is increasing.

00:39:38 And we add some to this.

00:39:41 And one more.

00:39:42 We add some to that, too.

00:39:45 And now we'll go back to the beginning and add some more.

00:39:48 As we add some more, we'll see if anything happens.

00:39:54 And we add some more to this.

00:39:56 We'll see if anything happens.

00:39:58 And we'll add some more to this.

00:40:02 And we'll add some more to this.

00:40:06 And some more to that.

00:40:11 And some more to this.

00:40:16 We'll go back and add some more here, right?

00:40:19 More is better, right?

00:40:28 Okay.

00:40:29 Now what we'll do is take a few drops out of this dropper here and add them.

00:40:42 You're carefully counting what I'm doing here, right?

00:40:52 And then, in order for things to happen, we have to stir them up.

00:40:56 So we'll stir this up.

00:40:58 And we'll stir this up.

00:41:01 We really have to stir them for things to happen.

00:41:04 Stir this up, too.

00:41:07 Stir this up.

00:41:10 Stir this up.

00:41:14 Stir this up.

00:41:21 See, the more we stir them, the more we can make the color disappear.

00:41:25 And so we'll go on to a different dropper and add a few drops of this.

00:41:48 Okay, we'll go back to our stirring technique.

00:41:52 And you see, we can restore the colors quite easily.

00:41:57 And now, if we do the experiment quite right, we will go back to the original flask that I had.

00:42:04 I'll put this up front here.

00:42:06 And you watch very carefully with me to see if anything happens

00:42:09 I'll take these two colored solutions and pour them down here.

00:42:22 You see, that's what we do in chemistry.

00:42:24 We can make things appear and make things disappear.

00:42:28 If we know exactly what we're doing.

00:42:45 So, this series of experiments with the acid-base indicator,

00:42:49 series of acid-base indicators, is a very colorful set of experiments, of course,

00:42:55 because of the season that we are in now.

00:42:58 Now, I want to ask you all to shift your attention to this special part of the lecture table

00:43:08 where I have this long spiral tube.

00:43:12 And in this long spiral tube, I'm going to mix two chemicals.

00:43:18 One is blue in color and one is colorless.

00:43:22 And I'm going to mix those when we turn off the light.

00:43:26 So, it's very important for us to do this experiment in the dark.

00:43:29 And you watch very carefully to see what happens as we pour these two liquids when the lights are off.

00:43:36 So, we'll go here.

00:43:44 This experiment involves the production of light by mixing chemicals.

00:43:49 We call that chemiluminescence.

00:43:51 You all have seen the firefly.

00:43:54 The firefly reaction is called bioluminescence.

00:43:58 Now, we can turn the lights on again so we can see our way around.

00:44:03 And we do a few more experiments that are quite interesting and also involve chemiluminescence.

00:44:11 And to do this one more experiment involving chemiluminescence,

00:44:14 I want to call on my associate Fred Juergens to come out and do this experiment.

00:44:21 So, Fred comes out.

00:44:29 And you watch this.

00:44:31 He has this long tube.

00:44:33 And, of course, Fred's going to put his safety goggles on as we do this experiment.

00:44:38 And this experiment we're going to do in the dark again.

00:44:41 And you pay careful attention to what he's going to do.

00:44:43 He's going to light a match and then open the top of this tube and drop the match down the tube.

00:44:50 And we'll see what happens.

00:44:51 So, if we're ready, you turn off the lights.

00:44:54 And here we go.

00:44:55 You pay careful attention.

00:45:04 You'll do it again.

00:45:13 Off a chemiluminescent reaction.

00:45:15 I know it happens so fast.

00:45:17 I know it happens very, very fast.

00:45:21 And Fred is just taking the tube away.

00:45:23 But because it happens so fast, it might be helpful for us to look at it in slow motion, right?

00:45:29 So, let's look at it in slow motion and see if we can pick out any more details of this experiment.

00:45:38 Here we go.

00:45:40 There you see the match.

00:45:42 I think he got it in this time.

00:45:47 And there is the liquid, which is a volatile liquid and a gas.

00:46:01 Okay.

00:46:02 Now, what we're going to do is take a quick look at the Christmas tree that we started.

00:46:07 Let's take a quick look at the Christmas tree and see if it is.

00:46:10 Oh, there you see.

00:46:12 It's beginning to get trimmed.

00:46:14 There are decorations on it.

00:46:16 We'll let this go a little bit longer and see what happens.

00:46:20 Now, in doing experiments, we try, as I said all along, to make observations.

00:46:26 And one of the people who has been paying very close attention to what has been going on here is Dean Cronin.

00:46:33 Now, because he's paid so close attention, I think he is qualified now to help me do some of the experiments.

00:46:38 Don't you think so?

00:46:40 All right.

00:46:41 Dean Cronin, if you come out here.

00:46:45 And I see that you're wearing eye protection, and so you're all set to go.

00:46:49 So what I would like to ask you to do is to help me by taking the contents of the beakers in the back row

00:46:56 and mixing them with the contents of the beakers in the front row.

00:47:00 And as you add the contents, when you finish adding one set, you start counting 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

00:47:08 And then you start the next one.

00:47:10 All right? Please.

00:47:16 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

00:47:22 And you start the next one.

00:47:30 Now count again.

00:47:31 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

00:47:38 Start the next one.

00:47:41 He's doing a good job, right?

00:47:46 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

00:47:55 Very good, very good.

00:48:02 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

00:48:11 10.

00:48:14 11.

00:48:16 12.

00:48:17 Let's start the next one.

00:48:25 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

00:48:32 Let's start the next one.

00:48:34 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

00:48:48 Start the next one.

00:48:51 As soon as you start the next one, the color changes. Watch.

00:48:55 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

00:49:05 Very good, very good.

00:49:07 Very good.

00:49:16 1, 2, 3, 4, 5, 6, 7, 8, 9, 10.

00:49:24 Very good. Thank you very much. Thank you.

00:49:31 This is an example of what we call a clock reaction.

00:49:35 And the colors appear if we use the same cadence when we're counting.

00:49:39 Of course, we weren't doing that.

00:49:41 And, of course, the colors that we expected didn't always appear on the exact count of 10.

00:49:47 But this is an example of a clock reaction.

00:49:49 What I want to show you now is an example of a similar kind of reaction,

00:49:55 but where the changes are...

00:49:57 Well, let's see what the changes are.

00:49:59 We take this colorless liquid and we add it to this large beaker.

00:50:04 And there's a magnetic stirrer there mixing things up.

00:50:07 And we add more liquid from a different flask into the same beaker.

00:50:13 And then we add the third reagent.

00:50:18 And you see that there's a color change already.

00:50:21 And still more change.

00:50:24 And more change taking place.

00:50:30 Now, this is not a clock reaction.

00:50:35 We call this an oscillating chemical reaction because the colors continue to oscillate.

00:50:40 And one of the fascinating things about chemistry

00:50:43 is that we try to understand why this behavior takes place.

00:50:47 And that's why we do research in order to understand this behavior.

00:50:51 And we can watch this for a period of time.

00:50:54 We can see the color changes.

00:50:56 We can see that the duration of each color changes as the reaction proceeds.

00:51:00 For example, the blue color now is lasting a little bit longer than it was before.

00:51:05 So this is a typical oscillating reaction that we can watch and we can examine and study.

00:51:14 Now, what I'd like to ask you to do is to pay close attention

00:51:20 to what I have over here where I have this flask.

00:51:26 And it has a liquid in it.

00:51:28 And what we want to try to do is carry out an experiment

00:51:33 by taking the liquid out of this flask

00:51:37 and pouring it down on the top of the lecture table.

00:51:41 So let's do that and see what happens.

00:51:51 You see the liquid is changing to a solid.

00:52:01 And this process we call crystallization.

00:52:05 We are crystallizing this solid from a supersaturated solution

00:52:10 that contains a salt, namely sodium acetate.

00:52:14 And you see we can keep doing this.

00:52:16 If you have a steady hand, you can make a very long candle-looking object out of it.

00:52:23 So this is the crystallization of sodium acetate.

00:52:26 Let's take a quick look at our Christmas tree and see how our Christmas tree is doing.

00:52:32 You see, again, the color of the blue copper ions is coming into view here.

00:52:39 And the silver is depositing on the tree.

00:52:42 And it looks like a very nicely decorated Christmas tree.

00:52:47 Now, in order to keep up the festivities and in keeping with the season that we are in,

00:52:53 we need to prepare different ornaments that we can use with the tree.

00:52:59 And so to prepare these ornaments, I have asked Fred Juergens again

00:53:05 and my other associate, Vince Jenna, to come out

00:53:08 and show us how Christmas ornaments can be prepared.

00:53:11 So, fellows, if you're ready, come on out here.

00:53:24 And they both have these flasks, large flasks now.

00:53:27 They're pouring different liquids into them.

00:53:31 And what they will do is carry out a chemical reaction inside each of the flasks.

00:53:37 You see, there is evidence of a chemical change already because the color has changed.

00:53:42 And what they will do is mix the contents very carefully.

00:53:59 You're beginning to see more changes?

00:54:02 What kind of changes are you seeing?

00:54:06 Yeah, the liquid is turning black.

00:54:09 And they continue to shake and...

00:54:12 No, these are shaking. I'm not shaking.

00:54:14 Oh, they're... OK.

00:54:18 And the glass is getting to be... what?

00:54:22 More shiny, right?

00:54:24 If you watch carefully, you'll see evidence for more chemical change.

00:54:35 Sometimes, you know, chemical reactions behave the way you want them to behave.

00:54:40 Sometimes they take a little bit longer.

00:54:43 That's one of the things that we do when we study chemistry.

00:54:46 We learn to be patient.

00:54:48 And we learn to be very understanding about controlling the behavior of chemicals.

00:54:57 Now, what is happening here is that the inside of each flask,

00:55:03 as far as I can see, is getting to be more shiny and more shiny, right?

00:55:08 And if they keep this up, as I hope they will,

00:55:11 maybe you're getting too tired.

00:55:13 Now, you see, what happens is that eventually,

00:55:17 what they will do is come up with a very big Christmas ornament

00:55:21 similar to the one that I have over here.

00:55:24 I'll show you what this one will look like.

00:55:26 It'll look like this.

00:55:28 And what they will be doing, if we carry out this long enough,

00:55:32 we will prepare a very large Christmas ornament

00:55:35 where we have silvered the inside of each of these flasks.

00:55:39 And we prepared this ahead of time, of course,

00:55:41 because it's bigger and it takes longer to do.

00:55:45 So, I think they're probably getting tired from doing this.

00:55:48 Maybe they're exhausted.

00:55:50 Why don't we set them down now?

00:55:51 Let's set them down.

00:55:53 And we'll carry out another experiment.

00:55:58 This experiment is actually an attempt on our part

00:56:03 to show you that you can do a lot of different things

00:56:06 with beakers and with chemicals.

00:56:08 We've done quite a few different things now,

00:56:10 but Fred now is going to show you a different way of using beakers.

00:56:15 So, watch very carefully.

00:56:22 Oh, dear.

00:56:24 I lost the tune.

00:56:25 I'm going to play one I know, okay?

00:56:40 Merry Christmas!

00:56:42 Merry Christmas!

00:56:52 I want you to take a close look at the Christmas tree here

00:56:56 that's really getting to be quite colorful and quite decorative.

00:57:00 And I'm going to carry out a whole series of other experiments,

00:57:06 but I think that time is becoming a factor here.

00:57:10 So, what we ought to try to do is, before we run out of time,

00:57:14 for me to express my gratitude to all of you for coming here

00:57:17 and for watching this program.

00:57:19 And I want to thank Dean Cronin.

00:57:21 I want to thank Santa Claus.

00:57:22 I want to thank Bucky Badger

00:57:24 and all the boys and girls and the members of the faculty

00:57:26 and everybody for being with us tonight

00:57:29 and making this a very special evening.

00:57:32 Merry Christmas, everybody, and Happy New Year.

00:57:34 Don't forget, chemistry can be fun.

00:57:40 Thank you.

00:58:10 ¶¶

00:58:40 ¶¶