00:00:00 This video was taken from a DVD, which itself was made from an unknown magnetic tape.

00:00:30 This video was taken from a DVD, which itself was made from an unknown magnetic tape.

00:01:00 This video was taken from a DVD, which itself was made from an unknown magnetic tape.

00:01:31 We have a fire extinguisher ready to be used just in case something goes out of control.

00:01:35 We're not planning on anything going out of control, but just in case.

00:01:38 As a safety precaution. I'll just set it aside to be out of the way, but ready to be used.

00:01:44 That balloon that I ignited with this big flame, what color was that balloon?

00:01:50 That balloon had a gas in it that combines with oxygen in the air...

00:01:55 ...in a very explosive way.

00:01:57 That gas is called hydrogen.

00:02:00 What we're going to do now is, as we always do in science, is repeat the experiments.

00:02:06 We're going to repeat the experiment with this other balloon that's right here.

00:02:10 But we're going to repeat the experiment in the dark.

00:02:13 Okay, so the light's out. Okay, here we go. Ready?

00:02:17 All the lights down. And...

00:02:20 Boom!

00:02:28 Now, were you able to see things differently with the lights out than with the lights on?

00:02:34 We want to keep that in mind.

00:02:36 Every time we do an experiment that has to do with the release of energy in the form of light...

00:02:41 ...we should try to keep the lights down.

00:02:43 Actually, I'd like everyone now to look at the monitors...

00:02:46 ...because we're going to look at that very last reaction in slow motion.

00:02:48 So watch and see. You won't hear any sound.

00:02:52 There's the torch coming to the balloon and boom!

00:02:55 There's that big... What color was that flame that you saw?

00:02:58 Red. Orange-red. Yes.

00:03:01 Well, we have other balloons that... Do you see other balloons that we have here?

00:03:05 How many other balloons do you see?

00:03:07 All right. What we're going to do is find out what's in these balloons.

00:03:11 What do you suppose we have in those balloons?

00:03:13 That the red balloons had in them hydrogen.

00:03:16 Some of you are saying helium.

00:03:17 You know from experience that helium-filled balloons are lighter than air.

00:03:21 So that's a very good guess.

00:03:23 I will tell you that helium is a gas which does not burn...

00:03:26 ...like hydrogen did with the ignition with the torch.

00:03:31 So we'll try this balloon now.

00:03:33 Now I notice some of you are covering your ears.

00:03:36 Why are you covering your ears?

00:03:38 Because you learned that there might be some sound energy released, right?

00:03:42 So here, we'll try this balloon.

00:03:44 And...

00:03:46 What happened? That balloon...

00:03:48 Did that balloon have hydrogen in it?

00:03:51 That balloon had helium in it.

00:03:53 Helium is a gas lighter than air that does not burn.

00:03:57 It does not undergo this explosive reaction...

00:04:00 ...that we just saw and witnessed with the red balloons.

00:04:05 Now, because sound energy is released...

00:04:08 ...and because it might be possible to damage our eardrums...

00:04:11 ...I would like everyone to obey the safety rules...

00:04:14 ...before I do the next experiment...

00:04:16 ...by taking both fingers and putting them in your ears like this, okay?

00:04:20 I can't do that and do the experiment at the same time...

00:04:22 ...so I will use some earplugs that I have with me.

00:04:26 And I really would like you to protect your eardrums.

00:04:29 So if you can hear the sound of my voice...

00:04:31 ...that means you don't have your ears well protected.

00:04:35 Now I can't hear you back, but I see some of you smiling.

00:04:38 That means you heard what I just said.

00:04:40 So I'd like you to protect your ears as much as possible...

00:04:44 ...as we go over to the next balloon that we have over here.

00:04:48 Ready?

00:05:03 Now that balloon had in it a mixture of hydrogen and oxygen.

00:05:08 There was more oxygen available for the hydrogen to mix with...

00:05:11 ...when the ignition process took place.

00:05:14 As we always do in science, we're going to repeat the experiment...

00:05:17 ...and we'll do it one more time in the dark.

00:05:19 So please protect your ears one more time.

00:05:23 And we'll turn the lights down.

00:05:28 All the way down. Are you ready for this?

00:05:37 All right.

00:05:45 Again, were you able to see things differently with the lights off...

00:05:48 ...than with the lights on?

00:05:50 That's a very important thing to keep in mind.

00:05:52 Let's take a closer look at this in slow motion once again.

00:05:56 You won't hear any sound, but you will see...

00:05:59 ...the torch coming closer to the balloon and ignition.

00:06:03 There.

00:06:05 And you'll see it was a much faster reaction...

00:06:07 ...than the one with the balloon that had only the hydrogen in it.

00:06:11 Now as we do experiments in my laboratory...

00:06:14 ...you never really know who is going to show up.

00:06:17 We get lots of special guests. All of you are special today.

00:06:20 But you never really know who might drop in as we go with our experiments.

00:06:24 Ho, ho, ho, ho, ho!

00:06:26 Merry Christmas!

00:06:28 Merry Christmas!

00:06:30 Ho, ho, ho, ho, ho!

00:06:32 Ho, ho, ho, ho, ho!

00:06:34 Merry Christmas!

00:06:36 Ho, ho, ho, ho, ho!

00:06:38 Merry Christmas!

00:06:40 Merry Christmas!

00:06:42 Merry Christmas to you too, Santa.

00:06:44 Thank you for coming to my lab...

00:06:46 ...especially at this time of the year.

00:06:48 I know you're very, very busy.

00:06:50 Did you get my list, Santa?

00:06:52 Oh, yes.

00:06:54 You did get my list?

00:06:55 A long list.

00:06:57 Yes, well, I needed, I wanted some things...

00:06:59 ...and I hope that I get anything on my list.

00:07:01 I've been a good boy. Haven't I been a good boy?

00:07:03 Ho, ho!

00:07:05 Yes, I got some stuff here.

00:07:11 Well, oh, yes.

00:07:13 Here's something you asked for.

00:07:15 Oh, yes, I asked for a science book.

00:07:17 It's a hot item.

00:07:20 Can I open it and read something in it?

00:07:23 Sure.

00:07:27 You were right, Santa. This is a real hot book.

00:07:31 Thank you, Santa. This was on the top of my list.

00:07:33 You're welcome.

00:07:35 Oh, here's another thing.

00:07:37 Yes, I wanted some balloons.

00:07:39 I just love to do experiments with balloons...

00:07:41 ...and I'm going to do some more experiments with balloons...

00:07:43 ...and that's a good supply that I will use right away.

00:07:48 Oh, yes.

00:07:49 This is, uh, it's not real money.

00:07:52 It's just a piece of paper in the shape of a $10 bill...

00:07:56 ...and I'd like to show you, Santa, and everyone else...

00:08:00 ...what we can do with this.

00:08:01 I take this and hold it over the flame like so...

00:08:04 ...and it disappears into thin air, just like that.

00:08:07 You like that?

00:08:09 Yes, I love that one.

00:08:11 This is, uh, it's called flash paper...

00:08:14 ...as you and your elves well know...

00:08:16 ...because you prepared this for me.

00:08:18 Yes, I had some other things on my...

00:08:20 Oh, yes, I wanted this very, very much.

00:08:22 This is a bubble solution, which we will use...

00:08:25 ...in many experiments that we will do later on.

00:08:28 Anything else?

00:08:30 Let's see.

00:08:31 You asked for this.

00:08:33 Two pieces of glass tubing...

00:08:35 ...with a piece of rubber tubing in between...

00:08:37 ...and a clamp.

00:08:39 I don't know what it's for, but you asked for it.

00:08:41 There it is.

00:08:42 Well, it's for some special experiments...

00:08:44 ...which we will do, uh, later on too, Santa.

00:08:47 Thank you very much for everything that you have brought me...

00:08:50 ...and as a special salute to you, Santa...

00:08:53 ...I would like to, uh, ask Fred Juergens to come out...

00:08:56 ...our lecture demonstrator...

00:08:58 ...and, uh, give you this very special salute.

00:09:00 Ho, ho, hi, Fred.

00:09:02 Okay, Santa, you've seen some of the experiments...

00:09:04 ...that, uh, Professor Shakasheri's doing.

00:09:06 I've got some beakers set up here too...

00:09:08 ...and there are all kinds of things that you can do with beakers...

00:09:11 ...and so you can stir them...

00:09:12 ...and then you notice that there's some sound...

00:09:14 ...and so I set up a whole bunch of beakers here...

00:09:17 ...to serenade you for your special holiday, okay?

00:09:21 Ho, ho, ho, ho, ho, ho.

00:09:28 Ho, ho, ho, ho, ho, ho.

00:09:33 Ho, ho, ho, ho, ho, ho.

00:09:35 Thank you, Fred.

00:09:37 Thank you.

00:09:38 Ho, ho, ho, ho, ho, ho.

00:09:41 My favorite song.

00:09:43 Ho, ho, ho, ho, ho, ho.

00:09:46 Uh, Santa, I see that you have your science is fun button on...

00:09:49 ...and so I'd like to do some experiments.

00:09:51 Uh, are you, uh, ready and prepared to do some experiments?

00:09:54 Oh, wait, just a minute.

00:09:56 I've got something else in my bag.

00:09:59 Aha.

00:10:01 Oh, yes, your eye protection.

00:10:02 Very, very important that we have that.

00:10:04 This experiment that I'm going to do is...

00:10:07 ...with some small crystals...

00:10:11 ...that I will put on the...

00:10:15 ...tabletop like so...

00:10:17 ...and then I'm going to take this clear and colorless liquid...

00:10:20 ...out of this flask...

00:10:22 ...and I'm going to pour the liquid on top of the crystals.

00:10:32 Oh.

00:10:37 It looks like an upside-down icicle.

00:10:39 It sure looks that way, doesn't it?

00:10:43 I see notes of the North Pole, but they grow the other way.

00:10:58 This is actually...

00:10:59 You like that?

00:11:00 Ho, ho, ho, ho, ho, ho, ho.

00:11:03 Very good.

00:11:08 This is actually the crystallization of something called sodium acetate...

00:11:11 ...coming out of a super-saturated solution.

00:11:14 And I can tell you, Santa, that if I put my hand...

00:11:17 ...close to this upside-down icicle, as you called it...

00:11:21 ...that I feel warmth.

00:11:23 That's because this crystallization reaction...

00:11:25 ...releases energy in the form of heat.

00:11:28 Now, you don't have much heat up in the North Pole, do you?

00:11:30 Oh, no, it's very cold.

00:11:32 Well, I would like to give you this...

00:11:36 ...which actually has the same, very same chemicals in it...

00:11:39 ...as we just used, the sodium acetate and water.

00:11:43 And if you just press on it a little bit right here...

00:11:47 ...we'll see what happens.

00:11:49 Just press. There's a little coin in there.

00:11:51 Press on it.

00:11:52 A little coin.

00:11:53 Pressing.

00:11:54 Yes, yes.

00:11:55 Oh, it's turning white.

00:11:57 It's crystallizing, just like this one did.

00:11:59 It's getting hot.

00:12:00 Oh, I could use one of these for a hand warmer...

00:12:04 ...up at the North Pole.

00:12:05 And I would like you to keep that.

00:12:07 Oh, thank you.

00:12:08 And the instructions on it tell you how you can regenerate this...

00:12:11 ...for many, many, many times of its usage.

00:12:14 Thank you.

00:12:15 Thank you, Santa, for coming.

00:12:17 I know...

00:12:21 I know that you're very busy...

00:12:23 ...and you have to make many, many other stops.

00:12:26 But can you stay for the rest of this program?

00:12:28 Do you want Santa to stay?

00:12:32 I have a place saved for you right there, Santa.

00:12:34 Thank you.

00:12:35 And I wish you the happiest of holidays.

00:12:37 Thank you.

00:12:38 Merry Christmas!

00:12:39 Enjoy the rest of the program.

00:12:40 Ho, ho, ho, ho, ho!

00:12:42 Merry Christmas!

00:12:46 Well, Santa, we're going to do a few more experiments...

00:12:48 ...that I hope you will enjoy and like.

00:12:53 Let me take the candles out of the way, so we don't...

00:12:59 ...because we don't need them anymore.

00:13:01 And I'm going to do this experiment...

00:13:06 ...by taking two liquids.

00:13:12 They're actually...

00:13:15 What does this liquid look like?

00:13:17 Syrup.

00:13:18 It's not syrup.

00:13:19 It looks like oil.

00:13:20 It's not oil.

00:13:21 It looks...

00:13:22 Yeah, but it's not bad.

00:13:23 It's kind of a syrupy-looking liquid, right?

00:13:26 But it's not for consumption.

00:13:29 There's the other one, too.

00:13:31 Now, for a chemical reaction to take place...

00:13:34 ...what we have to do is mix the chemicals together.

00:13:39 And we can tell when a chemical reaction is taking place...

00:13:42 ...if there's a color change.

00:13:44 You see a color change here?

00:13:46 So we can tell that there is a chemical reaction taking place.

00:13:51 Some chemical reactions are very fast...

00:13:53 ...as we saw with the explosive mixtures we had in the balloons.

00:13:58 And some other reactions take a bit longer before they happen.

00:14:03 And we have to work very hard sometimes to make a chemical reaction go.

00:14:07 You can tell that I'm working hard at this, right?

00:14:10 My hand's getting tired from doing all this.

00:14:13 And lots of interesting things happen if we are patient.

00:14:17 That's what we should do when we do scientific experiments.

00:14:21 Be observant and be patient.

00:14:24 Well, what I'm going to do now, because I'm really getting tired...

00:14:26 ...I'm just going to catch my breath, stop this...

00:14:30 ...and see what might happen.

00:14:33 We'll keep an eye on this, you and I together.

00:14:37 And we'll see if there are any changes that might be taking place.

00:14:41 As we do that, what we will look for now is another experiment.

00:14:48 Whoops, something is happening here. Can you see it happen?

00:14:51 What's happening?

00:14:53 What's rising? Is the beaker rising? No.

00:14:56 What's in the beaker is rising, right?

00:14:59 So we have a chemical reaction taking place.

00:15:02 And let's get back...

00:15:06 We might be in trouble here.

00:15:09 This thing is getting out of control.

00:15:11 Now, let's stay in there. Now, stay in there, stay in there.

00:15:13 Won't listen to me, right?

00:15:15 Oh, well.

00:15:19 This is actually a chemical which we call a polymer.

00:15:24 It's called polyurethane foam.

00:15:27 It has a lot of interesting properties.

00:15:29 One of them is the one that we're looking at right now.

00:15:31 Another interesting property is that it's a good insulator.

00:15:35 It's used for insulation purposes in cold places like Madison...

00:15:40 ...and elsewhere around the country.

00:15:42 So this is a polymer, and it's called polyurethane foam.

00:15:47 Of course, you all know about this polymer.

00:15:49 What's this one called?

00:15:51 Styrofoam, right.

00:15:53 It's actually made of something we call polystyrene.

00:15:56 And I'm going to show you one property of this polystyrene.

00:16:01 This is a cup, so what do we usually put in cups?

00:16:03 A liquid, right?

00:16:05 So I have a clear and colorless liquid.

00:16:06 I'm going to put this in the cup like so.

00:16:08 And...

00:16:10 Oops.

00:16:11 What happened here?

00:16:14 The bottom fell out, right?

00:16:16 This liquid is called acetone.

00:16:19 Acetone is commonly found in nail polish remover.

00:16:24 And what the acetone does is it takes the foam out of the styrofoam.

00:16:28 It looks like the polystyrene is dissolving in there, but it really is not.

00:16:33 It's just collapsing.

00:16:35 And I will show you, very interestingly, if we take some of the packing materials...

00:16:41 ...that's made of polystyrene, also the peanuts, packing peanuts.

00:16:46 We can put those in there.

00:16:51 And you can see that they too collapse.

00:16:53 Again, we're taking the air out of the structure that the polystyrene mold...

00:17:00 ...molded polystyrene had.

00:17:03 All right. Well, you see, Santa and everyone else...

00:17:06 ...if you study chemistry and you know what you're doing...

00:17:09 ...not only can you make certain things appear, but you can make other things disappear.

00:17:15 All right.

00:17:16 Thank you.

00:17:23 I would like you to look now at this part of the demonstration table...

00:17:30 ...where I'm going to mix two liquids.

00:17:33 The first liquid is clear and colorless.

00:17:38 And the second liquid is clear but colored.

00:17:45 And these two liquids mix with each other.

00:17:48 Actually, they don't mix very well.

00:17:50 They form what we call an interface.

00:17:54 And I'm going to use these tweezers, reach in there...

00:17:59 ...and pick up what formed at the interface.

00:18:02 And put it on this roller.

00:18:04 And then turn the crank up.

00:18:11 Now we've got all day to do this, right?

00:18:14 This is a form of nylon, which is another example of the substances we call polymers.

00:18:22 And the nylon rope that's being formed in here...

00:18:29 ...the nylon rope that's being formed in this case is very, very long...

00:18:35 ...and it's formed again at the interface between the two liquids that were mixed together.

00:18:41 Well, enough of this, right?

00:18:51 All right. Now let me look at another polymer, a very interesting polymer.

00:18:55 It's a white powder. It happens to be a solid.

00:18:59 And I have about 5 grams of this solid.

00:19:02 I'm going to put it in this beaker, which is empty except for air.

00:19:06 So I'll just put in about 5 grams.

00:19:08 And this beaker has in it some water to which we added some food coloring...

00:19:13 ...just to enhance the visibility.

00:19:15 So I'd like you to help me now and see how many times...

00:19:19 ...I can mix the contents of this beaker with the contents of this beaker.

00:19:23 So I'm going to go back and forth as many times as I can, as fast as I can...

00:19:26 ...and you help me count, see how many times I can do this, okay?

00:19:29 Here we go.

00:19:31 I'm going to get all the liquid out, make sure it's all out.

00:19:34 Oh!

00:19:49 What has happened here is that that powder, that polymeric substance...

00:19:53 ...has absorbed many, many times its volume in liquid.

00:19:57 And this has formed now a gel.

00:19:59 This has a lot of practical applications, including one application in gardening.

00:20:04 If you want to keep some moisture away from certain parts of the garden...

00:20:07 ...you can sprinkle some of that and then remove it later on.

00:20:10 It also has a much wider practical application...

00:20:13 ...and a fairly common household item.

00:20:16 And many of you know where we can find the material that is being used here.

00:20:21 And what common household item do we have?

00:20:24 Yeah?

00:20:25 It could be in a candle, yeah, but it's not in a candle, no.

00:20:28 Diapers, yes, it's in diapers, yes, diapers.

00:20:32 I heard your voice, you said that, yeah.

00:20:34 And so diapers have the same chemical in them and it absorbs, of course...

00:20:38 ...the moisture and other things that need to be absorbed, right?

00:20:41 Now I want to show you an interesting property of this gel.

00:20:45 If you take some table salt and you sprinkle about...

00:20:50 ...maybe two or three grams of salt on top...

00:20:53 ...and then you mix the salt with the gel...

00:20:58 ...what this does, because the salt has what we call ions in it...

00:21:04 ...it has ionic properties, sodium ions and chloride ions...

00:21:09 ...those ions destroy the gel feature that we observe...

00:21:14 ...and you can see now the gel is becoming more liquidy.

00:21:18 And the more you mix, the more you destroy the gel.

00:21:22 And, of course, we now can go back and add the liquid this way.

00:21:26 Now you want to count again? You want to go back to counting?

00:21:29 Well, it didn't all come out, right?

00:21:31 It didn't all come out because the salt has not gotten...

00:21:35 ...all the way to the bottom of the gel.

00:21:39 Okay, we'll do it one more time, okay?

00:21:42 Almost! Right?

00:21:47 All right, we did that. All right, very good.

00:21:52 You don't need helium to make a balloon float.

00:21:56 You can make any ordinary balloon float.

00:21:59 All you need is a hairdryer.

00:22:01 Turn on the hairdryer and point it straight up.

00:22:04 Hold the balloon over the hairdryer and let it go.

00:22:07 Watch the balloon float.

00:22:09 Pass your hand between the balloon and the hairdryer...

00:22:11 ...and watch what happens to the balloon.

00:22:14 Stay tuned, there are more fun balloon experiments coming up.

00:22:22 Now I would like you to focus your attention on this part of the lecture table...

00:22:27 ...where we have in front of me a series of cylinders.

00:22:31 How many cylinders do you see in front of me?

00:22:33 They're glass cylinders.

00:22:35 They're tan cylinders and they have what in them?

00:22:39 They have colored liquids in them, right?

00:22:42 And you can see they are arranged in a special order.

00:22:45 They're arranged by pairs according to the color of the liquid that's inside.

00:22:49 I'm going to use the gloves to protect my hands from the next chemical I'm going to handle.

00:22:56 This chemical is called dry ice.

00:22:59 This is solid carbon dioxide.

00:23:02 Its temperature is minus 78 degrees Celsius.

00:23:07 It's really very cold.

00:23:09 And it should not be handled with the bare hands because it will cause frostbite.

00:23:14 Solid carbon dioxide changes from being a solid to a gas directly without melting.

00:23:20 We call that process sublimation.

00:23:23 So sublimation is taking place right now, but we don't see it.

00:23:27 That's because carbon dioxide gas itself is colorless.

00:23:30 It's invisible.

00:23:32 It also has no smell.

00:23:33 We say it's odorless.

00:23:35 But yet the sublimation is taking place as we speak.

00:23:38 So I'm going to take...

00:23:40 Now you watch what I'm going to do.

00:23:41 I'm going to take some chunks of this dry ice and I'm going to put them in the cylinder in a very special way.

00:23:47 And you tell me what this special way is as we go along.

00:23:50 Okay?

00:23:54 Did I put the dry ice in every cylinder?

00:23:56 I put the dry ice in every other cylinder.

00:23:59 And you see the bubbles?

00:24:01 Those are the carbon dioxide bubbles.

00:24:03 They're coming from the what?

00:24:05 Sublimation of the dry ice.

00:24:09 And the carbon dioxide combines with the water to form carbonated water.

00:24:14 It forms carbonic acid.

00:24:16 And the colors that you see, you see some interesting color changes?

00:24:22 You like that?

00:24:23 Huh?

00:24:33 We see these color changes because we have dyes that change their color when we change the acidity or the basicity of the solution.

00:24:42 These dyes are called acid-base indicator dyes.

00:24:46 You notice the change was pretty rapid in this case, pretty rapid in this case, pretty rapid in this case too, right?

00:24:52 In almost all cases.

00:24:54 So that's one thing we have to be always paying attention to as we do these experiments.

00:24:58 Now, in addition to the bubbles, you see something coming off the top here.

00:25:02 What do you think this is called that's coming off the top?

00:25:04 No, steam is invisible.

00:25:06 You can't see steam.

00:25:07 It can't be carbon dioxide either because carbon dioxide is invisible.

00:25:11 What is it?

00:25:12 Fog.

00:25:13 Fog.

00:25:14 That's what it is, fog.

00:25:15 It's like clouds, right?

00:25:16 It's condensed water vapor.

00:25:18 The water vapor is condensing on the carbon dioxide that's coming out from the top of each cylinder that has the dry ice in it.

00:25:25 And you notice that the fog is moving downward.

00:25:28 That tells us, if we didn't know it, that carbon dioxide is denser or heavier than air.

00:25:34 And if we did know it, it just reminds us of it.

00:25:36 Isn't this a very pretty effect?

00:25:38 Huh?

00:25:45 Now, for the next part of the experiment, I need some hot boiling water.

00:25:50 And I don't see it here.

00:25:51 Can someone please bring me some hot boiling water?

00:25:53 Can I have some help in bringing that out, please?

00:25:55 Huh?

00:26:02 Hi, Bucky.

00:26:03 And welcome to my lab.

00:26:05 Bucky, I see you have your goggles on, which is very, very good on your part.

00:26:09 And so, together we're going to do this experiment.

00:26:12 This is the next part of this experiment.

00:26:15 This is a, what's this?

00:26:17 What is this called?

00:26:18 That's a dish fan.

00:26:20 It's empty except for air, right?

00:26:22 I'm going to take the hot water that Bucky brought in and put it in.

00:26:25 You see anything coming off the top?

00:26:27 No, steam is invisible.

00:26:29 You can't see steam.

00:26:31 It's water vapor.

00:26:33 It's water vapor, condensed water vapor.

00:26:36 Water vapor itself is also invisible.

00:26:39 So I'm going to take some more dry ice and dump the dry ice in this hot boiling water.

00:26:45 Whoa!

00:26:48 Oh, my God.

00:26:56 I'll leave Rudolph tonight.

00:27:00 This is how they make fog in the movies sometimes.

00:27:03 They take hot boiling water and add dry ice to it.

00:27:08 You like this, Bucky?

00:27:10 Huh? Bucky likes this.

00:27:11 Do you like this, too?

00:27:12 All right.

00:27:16 Thank you.

00:27:22 Bucky, I'm so glad you're able to come to my very special Christmas lecture.

00:27:26 This is the 28th year that Bucky makes an appearance in my special program.

00:27:30 And, Bucky, I know you're getting ready for final exams.

00:27:33 Are you studying, Bucky?

00:27:35 Are you going to graduate in time, Bucky?

00:27:37 You're going to make it in four years?

00:27:39 Four years.

00:27:40 Bucky's going to graduate in four years.

00:27:43 Good job, Bucky.

00:27:47 Bucky is pretty smart.

00:27:48 And I know, Bucky, you have to go study for final exams.

00:27:50 But would you like to stay for the rest of this program?

00:27:53 Would you like Bucky to stay?

00:27:58 All right.

00:27:59 I have a special place for you right next to Santa.

00:28:03 I'm going to do some experiments at this end of the table.

00:28:07 I'm going to use a very cold substance, even colder than dry ice.

00:28:11 This is called liquid nitrogen.

00:28:14 Liquid nitrogen is a liquid at a temperature of minus 196 degrees Celsius.

00:28:23 Very, very cold.

00:28:24 And it's kept in what we call a Dewar flask.

00:28:27 It's really a thermos bottle.

00:28:29 That's what it is.

00:28:30 And it's a liquid, and it boils at minus 196 degrees.

00:28:34 You can see it's a colorless liquid.

00:28:36 You see some stuff that comes out of the mouth of this Dewar flask?

00:28:39 Yeah.

00:28:40 Yeah, what is it called?

00:28:42 Condensed water vapor, right?

00:28:43 That's what it is, condensed water vapor.

00:28:45 So we're going to take a smaller Dewar flask and fill it up.

00:28:49 And then I have a cylinder.

00:28:55 I have a gas cylinder filled with oxygen gas.

00:28:59 This cylinder that contains the oxygen is going to be the source of gaseous oxygen

00:29:07 that I will allow to flow through this copper coil,

00:29:10 which I will put inside a thermos bottle, a bigger one.

00:29:14 That will be filled up with the liquid nitrogen.

00:29:23 And then what I'm going to do is turn the valve on and allow the gas to pass through.

00:29:31 Can you hear the gas coming through?

00:29:35 And if you watch closely, you begin to see something interesting happen.

00:29:39 I just let go of this piece of tubing, and it's held up in the air like that, right?

00:29:44 That's because the cold liquid coming through,

00:29:47 which I will collect in this tube,

00:29:55 is liquid oxygen.

00:29:57 And we're going to examine the properties of liquid oxygen and liquid nitrogen in just a moment.

00:30:02 This is a very cold liquid.

00:30:04 It is a liquid that boils at a temperature different than liquid nitrogen.

00:30:11 If liquid nitrogen boils at minus 196 degrees Celsius,

00:30:15 and liquid oxygen is able to be condensed in liquid nitrogen,

00:30:19 then the boiling point of liquid oxygen must be either higher or lower.

00:30:23 The boiling point of liquid oxygen must be either higher or lower.

00:30:26 Don't let the minus sign confuse you.

00:30:28 Think about that in terms of the condensation of the liquid.

00:30:32 So let me just now stop this.

00:30:37 Take this out and set it down carefully.

00:30:41 And I'll lift this up, and you see what color is liquid oxygen?

00:30:45 Yes, it's pretty blue, not just blue, right?

00:30:48 Well, it is really blue.

00:30:50 And I'm going to do an experiment with this magnet that I have.

00:30:54 I'm going to show you how powerful this magnet is.

00:30:56 I'm going to take my pocket knife, put my pocket knife in there.

00:31:01 Whoops, see, it's really held in there tightly.

00:31:04 I can even lift it up with that.

00:31:06 That's how powerful this magnet is.

00:31:08 And what I'm going to do is take the liquid nitrogen

00:31:11 and let it pass through the poles of the magnet.

00:31:14 And see what happens?

00:31:16 There's nothing.

00:31:17 The liquid nitrogen passes through.

00:31:18 That's because the nitrogen has no magnetic properties

00:31:22 similar to the pocket knife that I used.

00:31:24 But if I take the oxygen, I hold this very carefully.

00:31:27 Let me put the gloves on because it is safer that way, right?

00:31:32 I don't want to get frostbite.

00:31:34 And put the liquid oxygen through the poles of the magnet.

00:31:37 You see that the liquid oxygen stays in there until it evaporates.

00:31:43 That tells us that liquid oxygen has magnetic properties.

00:31:46 We call that paramagnetic liquid.

00:31:51 So let's do it again and see what happens.

00:31:53 It sticks in there until the liquid evaporates.

00:31:58 This is probably the first time for many of you

00:32:00 that you've ever seen a liquid held between the poles of a magnet, right?

00:32:03 Here we go, the last time, okay?

00:32:05 APPLAUSE

00:32:12 Now the liquid oxygen in this form is very concentrated.

00:32:17 That's why we need to keep sparks and flames away from it.

00:32:21 And I'd like to show you one other interesting property of liquid oxygen.

00:32:27 I've got this beaker and I have a cigarette here.

00:32:31 Let me just light the cigarette.

00:32:33 CLICK

00:32:34 CLICK

00:32:35 CLICK

00:32:36 CLICK

00:32:37 CLICK

00:32:38 CLICK

00:32:39 CLICK

00:32:40 CLICK

00:32:41 CLICK

00:32:42 People like this stuff?

00:32:44 So I'm going to put that cigarette in there

00:32:47 and then I'm going to take my liquid oxygen.

00:32:50 And you're watching this, right?

00:32:52 Here we go.

00:32:53 APPLAUSE

00:33:05 That's what I think you should do with all cigarettes.

00:33:10 Alright, so let's do some more experiments with balloons.

00:33:15 We have this balloon that's up here.

00:33:18 I want to bring this balloon over to the other side.

00:33:20 And I'm going to take some liquid nitrogen, if I have some left here.

00:33:26 I have some left here.

00:33:29 Doing experiments with balloons is a lot of fun.

00:33:33 Do you remember what was in the other green balloon before?

00:33:36 Yes, helium.

00:33:38 So what I'm going to do is take the liquid nitrogen and put it on top of the balloon.

00:33:42 Some of you are covering your ears, I can see that.

00:33:44 Because you learned from experience what might happen, right?

00:33:46 So what's happening in this balloon, as the liquid nitrogen cools off the helium atoms,

00:33:52 the balloon is collapsing, right?

00:33:54 It's shrinking.

00:33:55 So I take the liquid nitrogen away

00:33:58 and the balloon goes all the way up to the ceiling.

00:34:03 APPLAUSE

00:34:11 I'd like to do some more experiments with balloons

00:34:13 and so I'd like my special assistant Elizabeth to come up now.

00:34:17 Are you ready to come and help?

00:34:19 Alright.

00:34:20 Come around.

00:34:21 APPLAUSE

00:34:26 Hello Elizabeth.

00:34:27 Hi.

00:34:28 And of course we have the goggles for you.

00:34:30 We're going to do some interesting experiments.

00:34:33 We're going to actually do an experiment with balloons

00:34:36 and an experiment with some dry ice.

00:34:39 So I want to get some more dry ice,

00:34:41 which I have over here.

00:34:42 And I'm going to crush this dry ice

00:34:46 to make it into a powder.

00:34:48 And then I'm going to put the powder inside this balloon.

00:34:53 So can you hold this up for just a second?

00:34:55 Sure.

00:34:56 And I want to get some dry ice.

00:34:57 I need my gloves, right?

00:34:59 Safety always is paramount, right?

00:35:02 So I need my gloves to handle the dry ice.

00:35:04 I put the, about four chunks of dry ice in there.

00:35:09 And then I'll just, we both have gloves, right?

00:35:11 We both have our goggles on, right?

00:35:14 Yeah.

00:35:15 So just powder this.

00:35:17 Now what's happening to the dry ice as we're crushing it?

00:35:23 Dry ice that's sitting in the bucket over there.

00:35:25 It's sublimating.

00:35:27 Yes, exactly.

00:35:28 It's changing from being a solid to a gas

00:35:31 directly through the process we call sublimation.

00:35:34 So I'm going to take this, make it into a powder.

00:35:37 And then I would like you to help me.

00:35:42 Let me hold this now.

00:35:43 Okay.

00:35:44 Can you take this scupula right there

00:35:46 and fill this balloon with dry ice?

00:35:50 Sure.

00:35:51 Powdered dry ice.

00:35:58 One more scoop.

00:36:00 Okay.

00:36:03 All right, the next thing I want to do

00:36:05 is take the balloon off of this funnel

00:36:06 and I'm going to tie it.

00:36:10 And what's happening to the dry ice all along?

00:36:14 It's subliming, right?

00:36:16 And when it sublimes,

00:36:18 what's it doing to the balloon?

00:36:21 It's inflating it.

00:36:22 It's inflating the balloon.

00:36:24 The gas pressure inside is sufficient

00:36:27 to inflate the balloon.

00:36:30 So we'll set this over here

00:36:32 and watch it and see what else might happen to it.

00:36:36 We have a whole bunch of balloons

00:36:38 that were brought over by you-know-who, right?

00:36:42 And can you help me inflate this balloon?

00:36:46 Sure.

00:36:56 How's that?

00:36:57 All right, that's great.

00:36:59 That's great.

00:37:01 I'm going to tie this balloon real quickly for you

00:37:03 and then I'm going to give you

00:37:05 this very long and sharp needle.

00:37:08 Okay.

00:37:09 It's safe to handle.

00:37:10 I'm just going to ask you,

00:37:12 can you put the needle through the balloon

00:37:14 without having the balloon pop?

00:37:18 I don't know.

00:37:20 Would you like to try it?

00:37:21 Sure.

00:37:22 All right, here you go.

00:37:28 That didn't work very well, did it?

00:37:30 Nope.

00:37:30 Well, perhaps there's a way to do this, okay?

00:37:36 Would you like me to try?

00:37:38 Sure.

00:37:39 All right.

00:37:44 First we inflate the balloon.

00:37:46 We let some air out, right?

00:37:48 And then what's the next thing we do?

00:37:49 Tie it.

00:37:50 We tie it.

00:37:51 All right, and then we take the needle.

00:37:53 And I'm going to take this needle

00:37:55 and I'm going to dip it in some Vaseline.

00:38:00 Vaseline, just to lubricate it a little bit.

00:38:02 All right?

00:38:03 So then I'm going to take this needle and stick it.

00:38:05 Where are you going?

00:38:08 Come back here.

00:38:10 Come back here.

00:38:11 That's okay.

00:38:12 You have confidence in what I'm doing, right?

00:38:14 Of course.

00:38:15 Well, come on back here then.

00:38:16 Come on back here.

00:38:17 All right?

00:38:18 You want me to do it first?

00:38:19 Okay, here we go.

00:38:20 See?

00:38:21 Now you can get closer, right?

00:38:22 Yeah.

00:38:23 See, it didn't pop, right?

00:38:24 Wow.

00:38:25 And we see the thread coming through

00:38:28 the two holes in the balloon.

00:38:28 You see that?

00:38:37 So what's happening to the balloon?

00:38:40 It's deflating.

00:38:41 It's deflating.

00:38:42 It's shrinking.

00:38:43 Of course it is.

00:38:44 It's got two holes in it, right?

00:38:45 Can you feel it?

00:38:46 Can you feel the air coming out?

00:38:47 Yeah.

00:38:48 Do you think this is a special balloon of some sort

00:38:50 or just an ordinary balloon

00:38:51 that Santa and his elves prepared for us?

00:38:54 I guess it's just ordinary.

00:38:56 I think it's ordinary.

00:38:56 Take the needle and put it through.

00:38:58 And now, you're right.

00:38:59 You knew that was going to happen, didn't you?

00:39:01 All right?

00:39:09 Well, is there any way I can do this at home?

00:39:12 Can you do this at home?

00:39:13 I suppose you can.

00:39:15 Let me suggest to you some ways

00:39:16 in which you can do this.

00:39:17 All right?

00:39:18 Here we go.

00:39:19 First you have to do is inflate the balloon.

00:39:27 All right?

00:39:28 What's the next thing we do?

00:39:29 Tie it.

00:39:30 Tie the balloon.

00:39:31 Right.

00:39:32 And the way you do this at home

00:39:33 because you don't have a long needle like this.

00:39:35 Most people don't, right?

00:39:36 Do you have this needle at home?

00:39:37 No, you don't.

00:39:38 But you do have at home our small pins, right?

00:39:41 You have small pins at home

00:39:42 and you also have some scotch tape at home.

00:39:45 So could you take a piece of scotch tape, please?

00:39:47 Sure.

00:39:48 And put it at the end of the balloon

00:39:51 opposite where we inflated.

00:39:52 Right there, yeah?

00:39:53 And then would you reach over for one pin?

00:39:57 And now you can stick that pin through the scotch tape.

00:40:02 There is one stab, two stabs, three stabs, four stabs,

00:40:06 as many stabs as you want.

00:40:08 And the balloon is not popping, right?

00:40:12 Oh, there are holes.

00:40:13 Yes, I can feel the air coming out.

00:40:15 Very good.

00:40:16 Now, what else can you do to this balloon?

00:40:19 You can put the pin someplace else.

00:40:21 What will happen?

00:40:22 It will pop.

00:40:23 You don't want to do that, do you?

00:40:24 Not particularly.

00:40:25 All right.

00:40:26 We'll leave this balloon over here.

00:40:28 Well, that was very good, Elizabeth.

00:40:30 Thank you very much for all the help that you have given me.

00:40:33 Happy holidays to you.

00:40:34 Happy holidays to you, too.

00:40:39 Do you want to try some fun experiments at home?

00:40:42 Check out the Science is Fun website at this address.

00:40:46 You'll discover fascinating facts about chemicals

00:40:49 and other great science information.

00:40:55 All right.

00:40:56 Now we'll do some more experiments with balloons.

00:41:00 Remember, Santa brought this, what did he call it,

00:41:02 whatever, two glass, piece of glass tubing

00:41:05 and a rubber tubing and a pinch clamp and so on.

00:41:08 Well, we're going to do some more experiments with balloons.

00:41:10 We're going to do an experiment

00:41:12 by taking this yellow balloon,

00:41:14 attaching it to the end of the glass tubing,

00:41:22 and then I'm going to inflate it.

00:41:23 So nothing happened.

00:41:25 How come nothing happened?

00:41:27 Because the pinch is, right, the clamp is pinching there.

00:41:32 Okay.

00:41:33 So we inflate this and we get another balloon

00:41:36 that Santa brought and we put this balloon,

00:41:40 we inflate this balloon like so.

00:41:45 We put this balloon at the other end

00:41:48 and now we have two balloons,

00:41:51 different colors and different size, right?

00:41:54 Now the question is, whoops, this one is slipping off,

00:41:56 this one is slipping off.

00:42:02 There.

00:42:05 All right.

00:42:06 Now the question is,

00:42:08 what would you predict will happen

00:42:10 if I release the clamp

00:42:12 that's pinching the rubber hose in here, huh?

00:42:15 Well, some of you,

00:42:17 I want you to think about this, right?

00:42:18 Some of you are thinking maybe

00:42:21 the big balloon will get smaller

00:42:23 and the small balloon will get bigger.

00:42:25 Some of you might be thinking

00:42:27 that both will become the same size, right?

00:42:29 How do we get to find out?

00:42:31 We just do it.

00:42:33 We do the experiment, right?

00:42:35 We cut out all this talking and do it.

00:42:37 So how do I do it?

00:42:39 Just let go?

00:42:41 And what happened?

00:42:43 The small balloon got smaller

00:42:45 and the big balloon got bigger.

00:42:47 Is that what you predicted?

00:42:49 Well, some of you are saying yes,

00:42:51 but most of you are shaking your heads and saying no.

00:42:54 Now I think everyone here

00:42:56 who has ever inflated a balloon

00:42:58 knows the explanation as to why

00:43:00 the small balloon got smaller

00:43:02 and the big balloon got bigger.

00:43:04 It's not like, you know,

00:43:06 other things that happen in society,

00:43:08 the rich get richer and the poor get poorer.

00:43:10 No, it's not like that, no.

00:43:12 There's an explanation for it.

00:43:14 When you inflate the balloon,

00:43:15 is it at the beginning or at the end?

00:43:17 At the beginning.

00:43:19 At the beginning is when you have to...

00:43:21 And so when the balloon is stretched out already,

00:43:24 then it is easier to pump it up some more

00:43:27 than it is to pump up a balloon

00:43:30 that has not been stretched as much.

00:43:32 By the way, we still have this balloon over here.

00:43:35 Remember what was inside this balloon?

00:43:38 Dry ice, right?

00:43:40 So let's see if we have some more liquid nitrogen

00:43:42 and we can put the liquid nitrogen on top of this balloon

00:43:45 and see what happens to it, all right?

00:43:47 Here we go.

00:43:49 We add the liquid nitrogen to it.

00:43:57 And this balloon has collapsed.

00:44:00 I'm out of liquid nitrogen here,

00:44:02 but you can see that it is actually...

00:44:05 I have more liquid nitrogen.

00:44:07 Not...

00:44:10 There we go.

00:44:19 And what's the white stuff inside the balloon?

00:44:22 Dry ice, right?

00:44:24 Its sublimation temperature is minus 78 degrees.

00:44:27 That's higher than the boiling point of liquid nitrogen.

00:44:30 So it's right there.

00:44:32 When it warms up, you know what's going to happen

00:44:34 when it warms up.

00:44:36 All right.

00:44:37 Here's one more experiment we're going to do with...

00:44:40 Well, let's see.

00:44:42 We're going to do it with... What's this?

00:44:44 It's a coffee mug, right?

00:44:46 And do you suppose I can hold this mug up in the air

00:44:49 without touching it?

00:44:52 Oh, some of you are saying yeah.

00:44:55 Some of you are saying no, all right?

00:44:58 I'm going to show you how you can use a balloon

00:45:01 and an empty coffee mug.

00:45:03 It's empty except for air.

00:45:05 It's empty except for air.

00:45:07 And let's watch and see what happens.

00:45:16 Right there.

00:45:24 Now, what do you suppose will happen if I let the air out?

00:45:28 It'll fall, right, so I better catch it first.

00:45:31 I let the air out, right?

00:45:33 And you all know how to do this, right?

00:45:35 You can try it at home.

00:45:37 What's important is that you try to think as to why it works, right?

00:45:41 Not just to show somebody a neat trick,

00:45:43 but think about the reason for it.

00:45:45 So we do it again.

00:45:52 And you can see it's just bouncing here, right?

00:45:55 And you can also see that if I don't release the air

00:45:58 and I try to pull it out, I have to work to pull it out,

00:46:01 and there, there, there, there it came out, all right?

00:46:03 So that's kind of a hint as to what might be going on.

00:46:07 What will happen to this balloon if I let go of it?

00:46:11 Let's find out, right?

00:46:13 So it just goes all over the place.

00:46:15 All right, so...

00:46:24 This experiment we're going to do in...

00:46:30 a fish tank, exactly.

00:46:33 And this fish tank is empty except for air.

00:46:37 What we're doing is adding some dry ice...

00:46:46 into the fish tank,

00:46:48 and the dry ice, of course, sublimes.

00:46:51 It changes from being a solid to a gas directly.

00:46:55 Now, Santa Claus brought me something else that I had asked for,

00:46:59 which is...

00:47:00 Bubbles! I love bubbles.

00:47:02 I like to play with bubbles. Don't you?

00:47:06 Well, what do you normally do?

00:47:08 You take some...

00:47:11 You take the wand out, right?

00:47:13 And you blow.

00:47:15 Oh, we can do better than that.

00:47:17 Just one bubble?

00:47:19 No bubble this time.

00:47:21 Three bubbles this time.

00:47:23 Oh, let's do better.

00:47:25 There we go.

00:47:27 Now what I'm going to do...

00:47:29 You see the...

00:47:31 is blow the bubbles on top of the...

00:47:34 dry ice.

00:47:38 What's happening to those soap bubbles is that they are what?

00:47:43 They're floating. What are they floating on?

00:47:46 Carbon dioxide.

00:47:48 They're not floating on air.

00:47:50 In air, you know what happens in air.

00:47:52 They go way down, right?

00:47:54 But they're floating on the carbon dioxide gas.

00:47:56 Where did the carbon dioxide gas come from?

00:47:57 From the sublimation of the dry ice.

00:48:00 We'll do this experiment with the burner.

00:48:05 And...

00:48:07 using a large flask like this

00:48:10 that has a colored liquid at the bottom.

00:48:12 You can see that, right?

00:48:14 This is actually an acid-base indicator.

00:48:17 And this is the color of the indicator

00:48:19 when the solution is not acidic.

00:48:21 In this flask, we also have some oxygen gas.

00:48:24 But we can't see the oxygen gas

00:48:26 because it is colorless and invisible.

00:48:29 So I'll take this either way like so.

00:48:32 And I'm going to use a solid called sulfur.

00:48:36 I'm going to take some sulfur.

00:48:39 Use this spoon.

00:48:43 I'm going to burn the sulfur.

00:48:48 When you burn sulfur in the flame like this

00:48:51 or any other way, you get sulfur dioxide.

00:48:54 And this burns in a very interesting way.

00:48:57 Actually, you can see the flame of the sulfur burning

00:49:00 if we turn the lights down.

00:49:02 So turn the lights down, please.

00:49:04 And you'll be able to see

00:49:06 the characteristic flame of the sulfur right there.

00:49:09 And if I take this and stick it inside the flask,

00:49:13 you'll see what happens.

00:49:19 That's because there's oxygen in there.

00:49:21 You like that?

00:49:23 Thank you.

00:49:32 And if we turn the lights back up,

00:49:35 very pretty glow, isn't it?

00:49:37 You can see that there are fumes there of sulfur dioxide.

00:49:40 Now, sulfur dioxide combines with water to form acid rain.

00:49:44 And if the solution becomes acidic,

00:49:46 what color is the liquid at the bottom now?

00:49:49 And as the sulfur dioxide dissolves,

00:49:51 do you see any change in the color?

00:49:56 Green, yes. And what else now?

00:50:03 So this is how we find out about acid rain

00:50:08 because sulfur dioxide causes acid rain to happen.

00:50:11 At this time, I'd like to invite Fred Juergens

00:50:14 to come out and do a special experiment.

00:50:22 Thank you.

00:50:24 I've got a long tube here

00:50:26 that's got a mixture of gases in it.

00:50:29 They're invisible to the naked eye,

00:50:32 but I know they're in there because I put them in there.

00:50:35 And you've learned from Professor Shakashiri

00:50:38 that sometimes when you put a match or a torch

00:50:42 to balloons that have gases in them,

00:50:45 something happens, right?

00:50:47 So we're going to do the same thing with this tube.

00:50:49 I'm going to light a match.

00:50:51 I'm going to stand up here on this stool.

00:50:55 Santa, thanks for warning me to be careful.

00:50:58 You know, I don't have my glasses on.

00:51:00 I really need a pair of safety glasses before I do this.

00:51:03 Thank you.

00:51:06 Okay, so we're going to do this in the dark.

00:51:09 I'm going to light the match.

00:51:14 And you can all see the match up here.

00:51:16 I'm going to take the stopper off.

00:51:19 And drop the match in.

00:51:30 We can see something inside that tube, Fred.

00:51:33 What's that?

00:51:35 Well, there's a yellow solid inside the tube now.

00:51:38 It's sulfur.

00:51:40 You know, Professor Shakashiri burned some sulfur

00:51:42 and made sulfur dioxide.

00:51:44 We were able to make sulfur in this reaction,

00:51:46 and it's inside of the tube now.

00:51:48 Fred, I would like you and everyone else

00:51:50 to take a look in slow motion

00:51:52 at this very same experiment that we just saw.

00:51:55 You won't hear any sound again.

00:51:57 There's Fred.

00:51:59 Oh, he's getting out of the way quickly.

00:52:10 I'd like everyone to know that Fred Juergens

00:52:13 has been the lecture demonstrator

00:52:15 at the university for 20 years,

00:52:17 and he's retiring in about a week or so.

00:52:19 And I have...

00:52:21 Yes.

00:52:23 Thank you.

00:52:28 Thank you.

00:52:35 And this very special Christmas lecture

00:52:38 is dedicated to you, Fred,

00:52:40 in recognition of your excellent contributions

00:52:42 to our university,

00:52:43 to our community,

00:52:45 and to the profession.

00:52:47 Congratulations and best wishes to you.

00:52:49 Thank you very much.

00:52:51 I've got one more thing.

00:52:53 Thank you.

00:52:59 You know, before I leave,

00:53:01 I'd like to do one more demonstration for you.

00:53:03 Professor Shakashiri has been showing you

00:53:05 lots of things that are science,

00:53:07 because, in principle,

00:53:09 everybody can understand how to do these things.

00:53:12 There are other kinds of things

00:53:14 that you go to programs to see

00:53:16 that are called magic.

00:53:18 That's where only a few people know,

00:53:20 and the magician just doesn't tell you

00:53:22 how he cuts that lady in half,

00:53:24 or how he doesn't, you know.

00:53:26 And if nobody understands it,

00:53:28 we really call those kinds of things miracles.

00:53:30 Well, I'd like to show you one more demonstration,

00:53:32 if you can sort of focus on this beaker

00:53:34 right here in front of me.

00:53:36 I've got two clear and colorless liquids

00:53:38 that I will pour into this other

00:53:39 clear colorless liquid,

00:53:41 and we get this gorgeous yellow color.

00:53:45 Now, in one sense that's science,

00:53:47 because we know how to do that.

00:53:49 But isn't it a wonder

00:53:51 that we can mix colorless things

00:53:53 and see something yellow come out?

00:53:55 The wonders of science are just

00:53:57 what has kept me doing this job for 20 years.

00:53:59 You know, it's been a wonderful experience

00:54:01 being at the university.

00:54:03 I've enjoyed it tremendously,

00:54:05 but it's just time for me to do something else now.

00:54:07 So I'm going to have a good time

00:54:09 doing that, and thank you very much.

00:54:25 I'd like to ask you now to focus your attention

00:54:28 on this special glass spiral assembly.

00:54:31 And I'm going to take a clear but colored liquid

00:54:35 and mix it with a clear and colorless liquid.

00:54:37 I'm going to do this in the dark.

00:54:39 I'm going to turn the lights off.

00:54:41 We'll see what happens as I mix those in the dark.

00:54:58 This is an example of what we call

00:55:00 a chemiluminescent reaction.

00:55:02 This reaction releases energy

00:55:04 in the form of light, not in the form of heat.

00:55:07 Chemiluminescence is the name

00:55:09 of the reaction that we have just observed.

00:55:11 All right, so we go now

00:55:13 to this part of the lecture table

00:55:15 where I have a large beaker.

00:55:18 In fact, I want you to look at this beaker.

00:55:21 The volume of this beaker is 4 liters.

00:55:25 If you look at this beaker,

00:55:27 you just learned how big 4 liters is.

00:55:29 You can't unlearn it.

00:55:31 You may forget it, but you can't unlearn it.

00:55:33 I put a Teflon-coated magnet in it,

00:55:36 and I'm going to then turn the motor on

00:55:38 so we can mix chemicals as I add them.

00:55:41 The first liquid is clear and colorless,

00:55:44 at least in the flask it is.

00:55:46 When I add it down there, it's not so clear.

00:55:48 And the second liquid is added.

00:55:52 Anything exciting happen so far?

00:55:54 Not really, just the volume change, right?

00:55:57 Then I add the third liquid.

00:56:05 Is there anything happening?

00:56:08 How come I don't see anything happening?

00:56:11 Because I'm not looking.

00:56:14 What's the big deal about looking?

00:56:16 The last time I looked,

00:56:18 the last time I looked,

00:56:20 the color of the liquid in the beaker was blue.

00:56:23 So I look right now, right this minute.

00:56:27 You tell me when to look, okay?

00:56:29 Right now, right now, right this second.

00:56:31 Be sure, right now.

00:56:33 See, it's blue.

00:56:35 Every time I look at it, it's blue.

00:56:36 You tell me when to look.

00:56:38 Right now, now, right now.

00:56:41 See, it's blue.

00:56:43 Every time I look at it, it's blue.

00:56:45 Right now, right this second.

00:56:47 Be sure, right now, right now, right?

00:56:50 Right now, blue.

00:56:52 Oh, keep looking, she said.

00:56:54 Keep looking.

00:56:56 Oh, wow.

00:57:07 I should be looking all the time,

00:57:09 like you are looking all the time.

00:57:11 Because if I don't, I miss out on important and interesting things

00:57:14 that you did not miss out on.

00:57:16 Well, this brings to an end

00:57:18 our very special Christmas celebration with you

00:57:21 this holiday season.

00:57:23 I wish you the best and the happiest holiday season.

00:57:25 And remember, no matter what you do,

00:57:27 that science is fun.

00:57:29 Thank you very much.

00:57:31 Happy holidays.

00:57:36 ¶¶

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