00:00:00 This is the first year that Shakhashiri incorporates live music into his Christmas lecture.

00:00:30 This is the first year that Shakhashiri incorporates live music into his Christmas lecture.

00:01:00 I will be doing a lot of experiments, and I will be obeying all the safety rules,

00:01:04 including having my goggles on.

00:01:06 And of course I have a fire extinguisher ready to be used,

00:01:09 just in case something goes out of control.

00:01:12 I'm not planning on anything going out of control,

00:01:14 and this fire extinguisher will be just here.

00:01:17 I'll take it out of your view so that you get to see everything very clearly.

00:01:23 You noticed, of course, that the balloon I brought in had in it a gas lighter than air,

00:01:28 as do all the other balloons that I have.

00:01:30 That balloon had in it the gas hydrogen,

00:01:33 and hydrogen combines with oxygen when the mixture is ignited in a very explosive way.

00:01:41 What I'd like to do is show you that same chemistry reaction in the dark.

00:01:48 So if we can turn the lights down, we can look at this balloon now.

00:01:53 And I bring the flame to it, and...

00:01:58 The lights are on.

00:02:08 Did you see that ball of fire?

00:02:10 What color was it?

00:02:12 Yellow, orange, red is what I hear now.

00:02:15 Did you hear sound energy being released when the explosion took place?

00:02:20 Yes.

00:02:21 Yes.

00:02:22 What I'd like you to do now is look at that same reaction in slow motion.

00:02:27 So let's look at this.

00:02:28 You won't hear any sound.

00:02:30 There's the flame, and there's the balloon about to be there.

00:02:35 There's that ball of fire.

00:02:37 And, of course, we don't hear any sound as we look at this in slow motion.

00:02:41 So we learn about the explosions differently

00:02:45 as we look at them with the lights on and with the lights off.

00:02:48 Let's see if I go on now to this balloon over here.

00:02:54 Now, I notice some of you are covering your ears.

00:02:57 It's because you learned that there might be some sound energy released.

00:03:02 So let's try this balloon, and...

00:03:04 What happened?

00:03:06 The balloon popped, but there was no fire.

00:03:09 The flame went out, so I'll relight this torch here.

00:03:12 That balloon had in it a gas lighter than air, and that gas is helium.

00:03:17 So helium is a gas that does not burn explosively or doesn't burn, period.

00:03:22 So let's go on now to the other balloons that we have,

00:03:25 and we'll see what happens as I put the torch to this balloon.

00:03:31 Ready?

00:03:32 Some of you are covering your ears again.

00:03:34 All right, here we go.

00:03:37 Oh!

00:03:47 Now, that was a different gas.

00:03:49 That's a gas also lighter than air,

00:03:51 and I will tell you that gas is called methane.

00:03:55 That gas combined with oxygen in an explosive way,

00:03:59 but the loudness of the explosion was not as great as it was in the case of hydrogen.

00:04:05 So let's repeat that last experiment in the dark

00:04:08 and look at this balloon now as I bring the torch to it.

00:04:13 Ready? Here we go.

00:04:17 With the lights back on...

00:04:23 you were able to see the light energy

00:04:26 that was released from that combustion reaction between methane and oxygen in the dark.

00:04:31 Let's look at that in slow motion

00:04:33 and see if we can learn more about the size and the color of the flame.

00:04:39 You like that?

00:04:40 Yes.

00:04:41 Thank you.

00:04:42 Now, we have one more balloon.

00:04:46 We can leave it alone or we can do something with it.

00:04:49 What shall I do with it?

00:04:51 All right, all right.

00:04:52 One of the things we learned today is that when balloons are ignited,

00:04:58 there may be a lot of sound energy being released.

00:05:01 So I would like everyone to protect your eardrums before I do this last balloon

00:05:06 by taking both fingers and putting them in your ears like so and push very hard.

00:05:11 Now, I can't do the experiment and do that at the same time,

00:05:14 so I have with me some earplugs, which I will use.

00:05:18 So I would like you to protect your ears by putting both fingers in your ears

00:05:24 and do that right now.

00:05:26 If you can hear the sound of my voice, that means you don't have your ears well protected.

00:05:31 Now, I can't hear you, but I can see you smiling.

00:05:34 That means you heard what I just said.

00:05:36 So please protect your ears as we go to the next balloon and do it in the dark.

00:05:42 One, two, three, four.

00:06:04 That balloon had in it a mixture of hydrogen and oxygen,

00:06:10 and that mixture is very, very explosive.

00:06:13 There was more oxygen available to the hydrogen to combine with,

00:06:17 and that's why we heard a louder report and we saw a different color flame.

00:06:22 Let's look at that last one in slow motion again and see what we can learn about that.

00:06:27 There's the torch coming to the balloon.

00:06:30 A much faster reaction, and the color of the flame, of course, was different.

00:06:37 So, chemicals, when they burn, they produce light energy.

00:06:41 They also produce sound energy.

00:06:44 There's so many different ways to produce sound.

00:06:47 For example, I can take a glass rod and tap on glass vessels.

00:06:55 That's one way of producing sound.

00:06:57 Or I can just knock on the table top.

00:07:00 A lot of different ways to produce sound.

00:07:03 For sound to be produced, we have to have a vibration.

00:07:07 In fact, you hear my voice because my vocal cords are vibrating and pushing the air,

00:07:14 and a sound wave is reaching your eardrum,

00:07:17 and then a signal goes from the eardrum to the brain.

00:07:20 That's how we hear.

00:07:22 There are many things that vibrate.

00:07:25 To vibrate, here is a piece of rubber.

00:07:29 It's been stretched and held in place by three nails.

00:07:33 And if I pluck this,

00:07:41 all I'm doing is producing a vibration that causes sound to be generated,

00:07:49 and we hear the sound.

00:07:51 There's so many other ways to do this.

00:07:53 For example, if I take a whistle and I blow into it,

00:08:01 there is a sound wave being generated

00:08:04 because a column of air is vibrating inside the length of this whistle.

00:08:09 In fact, if I take a piece and extend the length of the whistle,

00:08:16 you hear the difference?

00:08:21 If I extend it even more,

00:08:26 so the longer it is, what happens to the pitch?

00:08:32 The pitch goes down, right.

00:08:34 So let's do that.

00:08:39 So that's one interesting thing that we want to keep in mind.

00:08:42 The longer the tube where the air is vibrating, the lower the pitch.

00:08:48 For example, I have this tube, which is hollow.

00:08:54 If I blow in it, I just blow air.

00:08:57 But if I turn it like this,

00:09:12 There are so many different ways to produce sound.

00:09:23 And to help us understand and appreciate that a bit more,

00:09:28 I am right now going to call on a group of talented individuals

00:09:35 to help us understand what's going on.

00:09:38 So here comes Todd, followed by Brian, Mandy, Fred and Penny.

00:09:47 Remember now, to have a sound, we need something that vibrates.

00:09:54 And this something can be a stretched piece of rubber

00:09:58 or it can be a stretched piece of plastic.

00:10:01 For example, that's what Todd has.

00:10:04 And to produce the sound, we can hit it gently or hit it a little bit harder.

00:10:10 And the loudness of the sound depends on how hard we hit it

00:10:15 and on how much the plastic film is stretched.

00:10:19 So Todd, give us a drum roll and see.

00:10:23 It sounds pretty good, huh?

00:10:25 You like that?

00:10:32 That's one way of producing beautiful vibrations.

00:10:35 Let's see if we can listen to other vibrations.

00:10:39 Mandy, can you pluck one string on your cello?

00:10:43 How about plucking another string?

00:10:46 A third one?

00:10:48 A fourth one?

00:10:50 Now can you pluck them all very quickly?

00:10:54 Faster, as fast as you can.

00:10:59 Actually, there is a way in which you can even pluck them much faster than that.

00:11:03 That is to use the bow that she's holding.

00:11:05 The bow is made of horse hair

00:11:08 and some rosin has been put on the horse hair

00:11:11 so that when she pulls the bow across,

00:11:16 then she will pluck all four strings at the same time very fast.

00:11:21 So, Mandy?

00:11:26 You like that?

00:11:33 Remember, we can generate sound waves also by moving columns of air.

00:11:40 And that's what we have now in the tube that Fred is holding.

00:11:45 What's the name of that tube?

00:11:47 It's a clarinet.

00:11:49 So Fred has a mouse piece.

00:11:51 Inside the mouse piece there is what we call a vibrating reed.

00:11:55 So, Fred, would you please let us enjoy what you can do?

00:12:00 Can you move up the scale?

00:12:02 Yeah, I can do that by lifting my fingers off of the holes

00:12:05 so that I shorten the column of air.

00:12:12 You like that?

00:12:19 The second wind instrument we have is the saxophone.

00:12:22 So, Brian, can you do the same things that Fred just did?

00:12:29 That sounds very good, doesn't it?

00:12:36 The last wind instrument we have is the trumpet.

00:12:39 And the trumpet, of course, has a mouse piece.

00:12:42 Penny, can you blow air through the mouse piece?

00:12:45 No sound whatsoever.

00:12:47 We need to generate a vibration.

00:12:51 So could you attach the mouse piece to the trumpet and blow again?

00:12:55 Same thing.

00:12:56 So we must have a vibration.

00:12:58 So how do you do it, Penny?

00:13:09 But you actually do it with the trumpet close to your mouth, right?

00:13:12 Go.

00:13:15 Beautiful.

00:13:21 Now, how about hearing something from the Science is Fun Quintet.

00:13:25 Are you ready?

00:13:42 Bravo!

00:13:46 Very nice, very nice.

00:13:51 How about an encore?

00:13:53 Would you like an encore?

00:13:55 All right.

00:14:26 Bravo!

00:14:34 Hi there, Bucky.

00:14:35 And welcome to my lab.

00:14:37 I'm so happy to see you here again.

00:14:39 And I'm sure you and I would like to ask the audience to give our quintet another round of applause.

00:14:49 Bucky, you come with me.

00:14:51 Come on with me, Bucky.

00:14:56 Bucky, I know you've been studying for final exams, and they're coming up pretty soon, right?

00:15:02 And Badgers are successful again.

00:15:04 They're going to the Copper Bowl.

00:15:05 Isn't that neat?

00:15:12 I'd like to show you a few experiments, Bucky.

00:15:16 And I know you're observant.

00:15:18 You've been coming to these Christmas programs for many, many years.

00:15:23 Maybe someday you'll graduate, right?

00:15:26 Oh, no, no, Bucky.

00:15:32 What I'd like to ask you to do, Bucky, and everyone else,

00:15:35 is to focus your attention on these glass cylinders that have in them colored liquids.

00:15:41 I'm going to use a very cold substance called dry ice.

00:15:45 Dry ice is a solid that changes to a gas directly without melting.

00:15:50 We call that process sublimation.

00:15:52 And the temperature is minus 78 degrees Celsius.

00:15:56 That's why I use the gloves.

00:15:57 Yeah, it's pretty cold.

00:15:59 I use the gloves to protect my hands from frostbite.

00:16:02 So the sublimation is taking place all the time.

00:16:05 We just don't see it because carbon dioxide gas is invisible.

00:16:10 So what I'm going to do is take chunks of dry ice

00:16:13 and drop them in these cylinders in a very special way.

00:16:16 You can see what that special way is.

00:16:18 What is it?

00:16:19 Am I putting the dry ice in every cylinder?

00:16:22 In every other cylinder.

00:16:24 And we see bubbles.

00:16:25 Those bubbles are the carbon dioxide bubbles,

00:16:29 carbon dioxide gas bubbles,

00:16:31 coming from the sublimation that's taking place.

00:16:35 And we see lots of interesting things begin to happen.

00:16:38 And in some of the cylinders, look in this cylinder here,

00:16:42 the color has changed as it has in this cylinder,

00:16:46 as it has in that cylinder.

00:16:48 Color changes indicate to us that a chemical reaction has taken place.

00:16:52 We can also see something coming off the top of the cylinders here.

00:16:56 More color changes are taking place as time goes by.

00:17:00 And so these chemical changes are indicated by the color change.

00:17:06 That sounds pretty straightforward, doesn't it, Bucky?

00:17:09 Bucky, I know you've got to study for the finals,

00:17:11 but would you like to stay?

00:17:13 Can you stay for the rest of this show?

00:17:15 Would you like Bucky to stay for this show?

00:17:17 Thank you.

00:17:18 All right.

00:17:19 All right, Bucky.

00:17:20 I have a special place saved for you right over there.

00:17:24 Just for you.

00:17:25 So come on over, have a seat,

00:17:27 and enjoy the rest of the festivities that we have on this special occasion.

00:17:35 So, are you comfortable, Bucky?

00:17:40 All right, he is comfortable.

00:17:42 That's good.

00:17:43 All right.

00:17:44 Now, as we can see,

00:17:47 there is something coming off the top of the cylinders where I put the dry ice.

00:17:52 What's coming off the top of the cylinders is called,

00:17:55 what does it look like?

00:17:57 Now, it's not steam.

00:17:59 No, steam is invisible.

00:18:00 It's called fog, clouds.

00:18:04 What it really is, condensed water vapor.

00:18:06 The water vapor is condensing on the carbon dioxide

00:18:09 that's coming out from the sublimation process as we have seen it.

00:18:14 And you see now, we even have more colorful changes

00:18:17 indicating to us that a chemical reaction has taken place.

00:18:20 So, what I'm going to do is reach over and get this plastic dishpan

00:18:27 that's empty except for what's in it.

00:18:30 Air is invisible too.

00:18:32 And what I'm going to do is reach over to where I've been heating some,

00:18:36 boiling some water.

00:18:38 It's boiling now.

00:18:39 I'm going to use the gloves to protect my hands from the heat,

00:18:41 not from the cold.

00:18:43 Reach over and put the water in the dishpan.

00:18:48 What do you see coming off the top?

00:18:50 No, steam is invisible.

00:18:52 You can't see steam.

00:18:54 What we're seeing is condensed water vapor.

00:18:58 When it's cold outside and you blow your breath on your hand,

00:19:02 don't tell me you see steam.

00:19:04 You see condensed water vapor.

00:19:06 So, we're going to take some dry ice now and put the dry ice on.

00:19:13 I'm still here.

00:19:17 You notice that the fog is moving in a downward direction.

00:19:24 That's because carbon dioxide gas is heavier than air.

00:19:28 In fact, that's how they make fog in the movies sometimes,

00:19:32 by using hot boiling water and dry ice.

00:19:37 You also notice that at the beginning of this experiment,

00:19:41 the fog or the cloud did not move downward, but it moved upward.

00:19:47 And I would like you to think as to why that is so.

00:19:50 What is it that's different about the conditions of the experiment now

00:19:55 from the beginning of the experiment?

00:20:02 You can make a xylophone at home.

00:20:04 You need six glasses or glass bottles that are the same.

00:20:09 Pour a different amount of water into each bottle.

00:20:12 Tap the sides of the bottles with a metal spoon to hear what sounds they make.

00:20:16 You can tune your xylophone by adding or removing water from the bottles.

00:20:21 Then, create your own music.

00:20:24 What I'm going to do next is take a piece of copper,

00:20:33 which is sitting on this tripod, and I'm going to heat the copper

00:20:39 using a burner, which I will light.

00:20:45 And I want you to see what color the copper is right now,

00:20:52 and what's going to happen to it as we heat it.

00:20:56 Copper at room temperature is metallic, of course.

00:21:01 It has its own characteristic appearance.

00:21:04 But as we heat it, the copper becomes more reactive.

00:21:10 In fact, you can begin to see some color changes on the piece of copper.

00:21:16 The color changes are happening because a thin layer of copper oxide

00:21:23 is forming on the copper, and the oxygen from the air

00:21:28 is combining with the hot copper surface to form that copper oxide.

00:21:33 What I'm going to do next is turn off the burner completely,

00:21:39 and I'm going to, now it's completely off,

00:21:43 and then I'm going to open up this valve, which is connected to a hydrogen cylinder,

00:21:48 and I'm going to put the hydrogen on top of the copper oxide.

00:21:53 And see, we can change it from copper, there's copper, there's copper oxide.

00:21:58 There's copper, and copper oxide.

00:22:04 Applause

00:22:13 You really never know who might drop into my lab here.

00:22:16 We have had a lot of different visitors.

00:22:19 Ho, ho, ho, ho! Merry Christmas!

00:22:24 Applause

00:22:33 Ho, ho, ho!

00:22:34 Hello there, Santa, and welcome to my lab.

00:22:37 Thank you, Merry Christmas.

00:22:38 I'm so happy to see you again.

00:22:40 It's good to see you.

00:22:41 This is a very busy time of the year for you.

00:22:43 Did you get my letter?

00:22:44 I sure did.

00:22:45 And the list that was with it?

00:22:47 Oh, it was a long list.

00:22:48 Well, it was, well, did I get any of the things on my list?

00:22:54 Have you been good this year?

00:22:56 I think I've been good. Have I been good?

00:22:58 Applause

00:23:01 All right. Let me see what I've got in here.

00:23:04 All right.

00:23:05 Uh-huh.

00:23:06 I'm eagerly awaiting.

00:23:10 Uh-huh. A copper bowl.

00:23:12 A copper bowl. Well, the badges are going to the copper bowl.

00:23:14 Thank you. Thank you very much.

00:23:15 Applause

00:23:21 Did you say the badgers?

00:23:22 Yes, I said the badgers, yes.

00:23:24 And the badgers are in the bowl, right?

00:23:26 Laughter

00:23:27 Copper bowl, right?

00:23:28 Ho, ho, ho, ho!

00:23:30 Applause

00:23:31 Right, Becky?

00:23:32 Oh, let's see.

00:23:34 I think you asked for a musical instrument.

00:23:37 Yes, I did.

00:23:38 How about that?

00:23:40 Yes, that's a nice instrument.

00:23:43 Can you play it?

00:23:45 Can I play it? I don't know. Let's find out. I can try.

00:23:49 Let's see. You're supposed to hit those things, right? Is that what?

00:23:53 I think that's it.

00:23:54 That's it, okay.

00:23:55 Ding, ding, ding, ding, ding, ding, ding, ding, ding.

00:24:00 Ho, ho, ho, ho! My favorite song!

00:24:02 Applause

00:24:03 Very good. Very good.

00:24:07 I don't think I'll quit while I'm ahead here.

00:24:09 Let's see.

00:24:10 I had a few other things on my list.

00:24:12 Well, aha.

00:24:14 Oh, yes. I had this on my list.

00:24:16 That's kind of an interesting object.

00:24:19 Let's see. What do we do with it?

00:24:21 Just give it a spin.

00:24:24 I'll try it again.

00:24:26 It's kind of wet here, so let's dry this off.

00:24:31 You were better at this when you were younger.

00:24:33 Yes.

00:24:34 Laughter

00:24:39 Ho, ho, ho, ho!

00:24:41 Applause

00:24:42 Very good. Very good.

00:24:45 Thank you, Santa.

00:24:46 You know, in my lab we do a lot of experiments, a lot of different things,

00:24:49 and we try to understand why different things do what they do.

00:24:53 So I'd like the audience to think about what is going on here

00:24:57 when this is given a spin like that, and then...

00:25:01 Isn't that neat? Huh? You think about that.

00:25:03 All right. All right. Thank you very much, Santa.

00:25:06 That copper bowl reminds me of something.

00:25:08 Yes.

00:25:09 Mrs. Claus and I have a lot of copperware up at the North Pole,

00:25:12 and over the last 1,000 years it's become kind of tarnished.

00:25:15 Do you know how to get the tarnish off of it?

00:25:17 I can make some suggestions.

00:25:19 I mean, it's tarnished like some of this stuff here.

00:25:23 And you'd like it to look clean like this.

00:25:26 Ho, ho, ho, yes.

00:25:28 Mrs. Claus would love that.

00:25:30 So all you need to do, actually, is get some salt and some vinegar.

00:25:37 And what you do, and you get a couple of cotton balls or some paper towels,

00:25:44 you put some salt like so,

00:25:47 and then you have the vinegar added like so.

00:25:57 Okay?

00:25:58 And I'll close this off so we don't spill any of it.

00:26:02 Careful.

00:26:03 Careful.

00:26:04 And then what we do is we wet the cotton ball

00:26:07 and make sure there's some salt on it, too,

00:26:11 and we just rub it.

00:26:15 Oh, that's working really good.

00:26:18 While you're working on that, I have one more question.

00:26:20 All right.

00:26:21 From Mrs. Claus.

00:26:22 Yes.

00:26:23 She has some hard-boiled eggs in the refrigerator.

00:26:25 Yes.

00:26:26 Hard-boiled eggs.

00:26:27 Yes.

00:26:28 How do you tell the difference?

00:26:29 Do you know that?

00:26:30 I think so.

00:26:33 Oh, that looks beautiful.

00:26:34 Is this satisfactory?

00:26:35 Oh, I can show that to Mrs. Claus.

00:26:37 Yes, you can, indeed.

00:26:39 Let me see.

00:26:40 Thank you.

00:26:45 Well, I happen to have some eggs here.

00:26:48 And actually, I have two eggs.

00:26:51 And let's see if they look the same.

00:26:55 I can't tell the difference.

00:26:56 They're about the same size.

00:26:57 So suppose I take this one and give it a spin.

00:27:01 Look at this.

00:27:02 That spins really well.

00:27:03 That spins well.

00:27:04 Suppose I take the second one and give it a spin, too.

00:27:08 That doesn't spin as well, right?

00:27:10 It doesn't spin.

00:27:11 So one way in which you can tell the difference

00:27:14 between a hard-boiled egg and a raw egg

00:27:19 is to give it this spin test.

00:27:21 That's pretty easy to do, right?

00:27:22 Yes.

00:27:24 How do I know you're telling the truth?

00:27:26 Oh, Santa.

00:27:30 You want more proof.

00:27:32 Break it open.

00:27:33 Which one should I break, the raw one or the hard-boiled one?

00:27:36 Which one should he break?

00:27:38 The raw one.

00:27:40 All right.

00:27:41 This is the one that spins.

00:27:42 You see that?

00:27:43 OK.

00:27:44 So I'll break this one.

00:27:45 And you see that this is the hard-boiled one, right?

00:27:48 You know everything.

00:27:49 This one here, I better break it inside here, right?

00:27:52 Well, this was the raw one, all right?

00:27:57 Great.

00:28:00 Thank you.

00:28:01 I'll tell Mrs. Fogg.

00:28:04 Thank you, Santa.

00:28:06 Thank you.

00:28:07 I know your reindeer are probably waiting for you outside,

00:28:09 but can you stay for the rest of this program?

00:28:12 I'd love to.

00:28:13 Would you like Santa to stay?

00:28:14 I'd love to.

00:28:15 Merry Christmas.

00:28:16 I have a seat saved for you right next to Bucky.

00:28:18 Thank you.

00:28:22 At this time, I would like to call on Fred Juergens

00:28:26 to come out and make a very special presentation.

00:28:29 So here's Fred Juergens.

00:28:30 Thanks.

00:28:31 I'd just like to welcome Santa.

00:28:33 Thanks for coming, Santa.

00:28:37 And just for you, just for you,

00:28:39 I've prepared a set of special beakers,

00:28:43 and I'd like to show you what I'm going to do with them

00:28:45 with this glass rod.

00:28:47 Here we go.

00:29:02 There it is.

00:29:06 For you.

00:29:16 Very nice, Fred. How about an encore, Fred?

00:29:20 Okay, we've got Bucky here, so we ought to have an encore for Bucky, right?

00:29:46 Thank you very much, Fred. Thank you.

00:30:03 You know, we were doing a lot of experiments with bubbles,

00:30:06 and I'd like to continue to do some experiments with bubbles

00:30:11 that come in a carbonated beverage, such as this one.

00:30:16 There are lots of gas molecules pressurized inside this can.

00:30:22 I want you to just be quiet and listen and see what you can hear as I open this.

00:30:31 Did you hear that?

00:30:32 That's the release of the pressure from the carbon dioxide that is inside this can.

00:30:38 There's a lot of gas inside this can.

00:30:40 In fact, I'm going to show you, try to show you, let's see what happens.

00:30:44 I have a baby bottle here, except that I have replaced the nipple that has a hole in it,

00:30:51 I've replaced it with the rubber bulb from a medicine dropper.

00:30:55 And I want to show you how strong this rubber bulb is.

00:30:59 Let me just take it out here and put it back in.

00:31:02 Take it out. I'm going to try to inflate it.

00:31:11 It's a very strong piece of rubber.

00:31:13 I put it back in place, like so.

00:31:16 And then I will take the carbonated beverage and put it in the baby bottle.

00:31:23 You see bubbles?

00:31:26 Those are carbon dioxide bubbles coming out of the liquid.

00:31:31 I fill it all the way to the top.

00:31:34 And the next thing I'm going to do is put the screw cap on, tighten it.

00:31:40 What should I do next?

00:31:42 Oh, you've done this experiment before, huh?

00:31:45 Okay, I'm going to shake it and we'll see what happens.

00:31:51 There's a big bubble for you.

00:31:53 This is how much carbonation is inside the carbonated beverage that we have here.

00:32:00 Now, what we can do is release the pressure.

00:32:04 Of course, there are several ways to do that.

00:32:07 One is to try to do it fast, and then what will happen?

00:32:12 We'll make a mess, right?

00:32:14 I'll try to do it slowly and see if we can avoid making a mess.

00:32:20 And as the pressure is released, you can see that the...

00:32:24 Oops, some of it dripped out.

00:32:26 That's all right.

00:32:28 It's all safe to handle.

00:32:31 Of course, it's safe to drink.

00:32:33 So, this is then more about bubbles.

00:32:43 Of course, what we want to do now is have some more fun with additional items

00:32:48 that we can find around the house in the kitchen or elsewhere around the house.

00:32:52 And what I want to do is show you a few more experiments with bubbles.

00:32:56 Here's some water and a straw.

00:32:58 Usually, we use a straw to drink.

00:33:01 What I'm going to do now is use the straw to blow into the water.

00:33:06 Hot water.

00:33:11 I'm just making bubbles, right?

00:33:13 But there's nothing to hold the gas that I'm blowing in, in place.

00:33:17 So, what I'm going to do is add a little bit of detergent, like that.

00:33:23 And again, I'm going to blow gas.

00:33:32 And you see now that the soap film holds the bubbles in place.

00:33:44 Now, there are other ways to make bubbles.

00:33:48 And one way would be to take a dish, as I have over here, that you can use to generate some bubbles.

00:34:03 And what you do need is some laundry detergent.

00:34:06 And then you can add to the laundry detergent some, what am I adding?

00:34:12 Baking soda.

00:34:14 You put in about the same amount of each.

00:34:18 And mix them together, like so.

00:34:23 And then reach out for another household chemical that you might have around.

00:34:30 And that is?

00:34:34 What?

00:34:35 Vinegar.

00:34:36 So you put the vinegar in.

00:34:39 And that's another way of making bubbles.

00:34:42 And the fizzing that's happening is because the baking soda is combining with the vinegar, which has in it acetic acid.

00:34:51 And we've made some bubbles that way.

00:34:55 So, there still are other ways to make bubbles.

00:35:00 And to make foam, basically.

00:35:02 That's what we're doing.

00:35:04 We're going to take some whipping cream.

00:35:08 Put that, some of that anyway, in a pilsner like so.

00:35:17 And then blow.

00:35:29 What we're doing is introducing gas, in this case air, to the cream.

00:35:38 Of course, there's another way of doing this, right?

00:35:40 What's the other way of doing it?

00:35:42 Use what?

00:35:43 Use a beater.

00:35:44 Use a beater, you're right.

00:35:45 So that's what I'm going to do.

00:35:47 I'm going to take this cream that I have.

00:35:53 And let you take a good look at it.

00:35:58 I have a bowl.

00:36:00 I put some cream in.

00:36:03 And then I'll reach for my beater.

00:36:07 Which I happen to have here.

00:36:09 And...

00:36:20 Does this look like something that goes on around the house?

00:36:25 Yes.

00:36:27 And then go even faster.

00:36:37 And what happens to the cream when it's whipped like this?

00:36:40 It becomes whipped cream, I know that.

00:36:42 But what happens to it then?

00:36:43 It gets in to be a foam, right?

00:36:46 So you can see that it has a different texture and a different appearance than it did before.

00:36:53 And that's what we have inside, ready-made whipped cream like so.

00:36:58 Except that when we get the cream out, we have the liquid on the inside.

00:37:03 And there is a gas inside the can that propels the cream out.

00:37:07 So what we end up with is cream.

00:37:13 What do we do normally with cream?

00:37:15 We eat it, right, right, right.

00:37:17 We'll do a few more experiments with other things that are around the house and around the kitchen.

00:37:24 We'll come back to the cream.

00:37:27 You know what holds the cream is having a film, just like we had the soap film before, hold the gas inside.

00:37:36 So what I'd like to show you is this experiment over here,

00:37:40 where I have a balloon inside this glass flask that I'm going to now evacuate.

00:37:48 It's hooked up to a vacuum pump.

00:37:53 And I'm going to get the gas out of this glass vessel.

00:38:03 You can watch and see what's happening to the balloon.

00:38:10 Is anything interesting happening to the balloon?

00:38:14 The balloon is getting bigger.

00:38:16 The balloon is getting bigger because the pressure outside the balloon is getting to be less than the pressure inside the balloon.

00:38:25 And so the rubber is acting as a barrier to keep the gas inside.

00:38:34 So that's one thing we can do.

00:38:37 And, of course, what happens when I let the air back in?

00:38:45 The balloon collapses.

00:38:47 Well, it goes back to the original shape that it was in.

00:38:51 So I'm going to take this off now.

00:38:53 I'm going to show you what can be done and what will happen

00:39:00 If I take another round-bottomed flask and enter this flask, I will put some of this cream.

00:39:11 So.

00:39:18 Okay.

00:39:21 The next thing I will do is connect this to the vacuum pump and

00:39:37 we'll watch the cream and see what happens to the cream as we change the pressure on the inside.

00:39:46 Anything happening to the cream?

00:39:49 It's getting bigger.

00:40:14 Now what do you suppose will happen if I close this off, unplug the vacuum pump, and then let some air in?

00:40:28 Let's just do it and find out, right?

00:40:31 Alright, let's get back and do a little bit of more chemistry in our lab

00:41:00 by taking a bowl and I have, in this glass bowl, I have some water.

00:41:08 And I want to beat the water, but I don't want to use the same beater I used before because it's got some cream on it.

00:41:15 So I have another one here conveniently.

00:41:18 And so what we're going to do is simply beat the water.

00:41:26 See what happens now?

00:41:28 Beat as fast as you can.

00:41:30 You all have had this experience, haven't you?

00:41:33 Nothing really exciting happens.

00:41:35 You get some bubbles in there, but the bubbles are not held.

00:41:38 So what we're going to do next is take some flour.

00:41:43 This is wheat flour.

00:41:45 Add the wheat flour to the water.

00:41:48 Do we do this around the home or not?

00:41:50 Yes, we do it all the time.

00:41:53 We beat the flour and the water to make what?

00:41:59 To make dough, right.

00:42:01 And we can use the dough for a lot of interesting things that we can cook and enjoy.

00:42:08 I want you to look carefully at the dough because the dough is doing something very interesting.

00:42:15 Can you see how the dough is behaving differently than the water did?

00:42:20 The dough is climbing up.

00:42:25 And then when I stop, it flows down.

00:42:29 If I beat it again.

00:42:31 So this wheat dough has this interesting behavior that actually anybody who's done any cooking and baking of this sort knows about.

00:42:43 So I thought you might be interested in looking at that.

00:42:46 All right.

00:42:50 What I want to do is mix other household chemicals that we easily find around the house in this cylinder.

00:43:00 The first one I'm going to mix is a viscous liquid which is called what?

00:43:08 You can read the label.

00:43:10 All right, here it is.

00:43:11 I put some honey in.

00:43:17 Okay, yum, yum is right.

00:43:21 And then I will add on top of the honey, I will put some water.

00:43:32 And I'll do this carefully.

00:43:39 And I have now two liquids that are not miscible with each other.

00:43:46 They don't mix with each other and they have different densities.

00:43:50 I can take a third liquid that we have around the house which is what?

00:43:53 What's this one?

00:43:55 And I can add oil, olive oil in this case, on top of the water layer.

00:44:02 We know that water and oil don't mix, right?

00:44:07 So we have three layers and I can take still another liquid that we easily find around the house

00:44:15 and this is rubbing alcohol.

00:44:17 So I can take some rubbing alcohol and again add that carefully not to mix all the liquids together.

00:44:29 And you see we end up with four layers of liquids that have different densities

00:44:36 and do not mix with each other.

00:44:39 Actually, the top layer of the rubbing alcohol will mix with the water

00:44:46 if one were to take their hand and put it on top like this.

00:44:50 Let me do it this way and show you what happens.

00:44:52 You see that we have four layers now, right?

00:44:54 And without spilling this, see if we can mix those.

00:45:04 And the alcohol and the water will mix with each other

00:45:07 and the honey and the oil and the water will not.

00:45:12 So we started out with four layers and when the different bubbles come out

00:45:19 and the layers settle, we'll come and look at this again and we'll see how many layers we have.

00:45:25 Want to make your own volcano?

00:45:27 Here's what you need.

00:45:29 Powdered laundry detergent, baking soda, vinegar, a plastic glass or dish, and a tray.

00:45:36 Add several spoonfuls of laundry detergent and the same amount of baking soda to the glass

00:45:41 and mix them together.

00:45:44 Pour the vinegar into the glass and watch what happens.

00:45:52 I have a beaker and behind it there are three flasks with three different liquids in them.

00:45:59 I'd like everyone to know that this 1996 Christmas lecture

00:46:05 is dedicated to the memory of Professor Hubert Allier who died last October at age 93.

00:46:12 He was truly an international grandmaster of sharing the joy and fun and excitement

00:46:18 of doing chemistry with the public at large.

00:46:21 And I'd like to dedicate this to him by mixing these chemicals together.

00:46:27 Professor Allier taught at Princeton University throughout his career.

00:46:43 And these are the Princeton colors.

00:46:59 Now I'd like you to focus your attention on this large glass beaker that I have.

00:47:04 It has a volume of four liters and if you look at it carefully

00:47:09 you have just learned how big four liters is.

00:47:12 You can't unlearn it. You may forget it, but you can't unlearn it.

00:47:16 And into this beaker, which is empty except for air,

00:47:19 and this magnet that is coated with Teflon sitting on top of a magnetic stirrer,

00:47:26 what I'm going to do is mix different liquids that are clear and colorless

00:47:34 and we'll see what happens when these liquids are mixed.

00:47:41 Anything exciting happen?

00:47:50 It looks like it's the same as this one.

00:47:53 But is it?

00:47:58 This is...

00:48:04 This is a mixture of about eight or nine different chemicals

00:48:08 including something we call potassium iodate, hydrogen peroxide,

00:48:13 manganese sulfate, malonic acid, potato starch is in there,

00:48:18 sulfuric acid is in there.

00:48:20 And this yellow color that you see is the color of iodine,

00:48:24 what we in the vernacular call iodine.

00:48:26 The blue color that you just see here is the color of the iodine

00:48:30 combining with the potato starch.

00:48:32 And this mixture that has these different chemicals in it

00:48:37 continues to oscillate by generating and consuming what's getting generated

00:48:43 until one of the original reactants is totally consumed.

00:48:48 Now what I... You like that?

00:49:03 Now I'd like to ask Fred to give me a hand.

00:49:06 Here is Fred with the tall glass tube.

00:49:13 This glass tube looks wet on the inside.

00:49:17 I have a step stool here that I'm going to stand on.

00:49:21 This tube looks wet on the inside because it has a liquid in it.

00:49:26 It also has a colorless gas.

00:49:29 We can't see it because it's colorless.

00:49:32 And what I'm going to do is take the rubber stopper that's on the very top,

00:49:37 lift it up after I strike a match so I can drop the lit match into that tube.

00:49:45 And we're going to do this in the dark.

00:49:47 So I'll strike the match.

00:49:51 Take the top off.

00:49:53 Boom!

00:50:11 This experiment released energy in the form of light.

00:50:17 We saw that.

00:50:18 In the form of sound, we heard that too, right?

00:50:21 And also there's a deposit of this yellow substance on the inside of the tube.

00:50:28 That's sulfur.

00:50:29 What I'd like to have us do now is to look at this in slow motion

00:50:33 and see if we can learn more about this exciting experiment.

00:50:36 Again, we won't hear any sound.

00:50:38 There's the match being dropped in.

00:50:41 There I am trying to get out of the way.

00:50:51 Thank you.

00:50:57 All right.

00:50:58 Let's do another experiment.

00:51:01 Actually, let's do this experiment by taking a clear and colorless liquid

00:51:07 and mix it with a clear but colored liquid in this very special glass assembly

00:51:14 where there is a glass funnel at the top connected to a spiral glass tubing

00:51:19 which then leads to a receiving flask at the bottom.

00:51:22 So we'll mix those two liquids together in the dark and we'll see what happens.

00:51:27 So let's turn the lights off.

00:51:50 This mixture generated light energy, no sound energy,

00:51:57 and I can tell you by touching it, it's still at room temperature, so no heat energy.

00:52:02 When we mix chemicals together and we generate only light energy,

00:52:07 we have something called a chemiluminescent reaction.

00:52:11 So the phenomenon of chemiluminescence is what we have just seen here.

00:52:16 Of course, just about everyone knows about chemiluminescence

00:52:20 because you know about the firefly reaction.

00:52:23 The firefly reaction is bioluminescence.

00:52:26 It's taking place in a living organism that has a catalyst that makes that reaction go.

00:52:33 So let me now look at what I have down here.

00:52:37 Excuse me.

00:52:39 I have a flask and I have another flask that has some water in it.

00:52:47 I'm simply going to dump this water out.

00:52:57 It's not big enough, so I'll use another.

00:53:02 All right, and now what I'm going to do is mix into this flask two liquids like so.

00:53:12 Here's the first liquid.

00:53:15 And here's the second liquid.

00:53:20 And then I'll put the rubber stopper on top and swirl it around.

00:53:31 We learned today, among other things,

00:53:34 that a color change indicates to us that a chemical reaction is taking place.

00:53:39 Do you see a color change here?

00:53:42 Is there a change at all?

00:53:44 We started out with two clear and colorless liquids,

00:53:47 and now we have a dark liquid.

00:53:49 What else do you see happening here?

00:53:53 You see my hand getting tired from doing this, I know that.

00:53:56 Well, what else do you see?

00:53:57 I see something here.

00:54:01 I see my own reflection here.

00:54:04 It's getting shiny, right.

00:54:06 The inside of the flask is getting shiny.

00:54:22 I'm going to put this down.

00:54:25 You can see that.

00:54:26 And I would like to show you what I prepared ahead of time,

00:54:30 before you came in.

00:54:32 This one.

00:54:48 I'd like to close this very special presentation

00:54:51 by reminding you to enjoy doing experiments,

00:54:55 to have fun as you do experiments safely,

00:54:59 and to remember, no matter what you do,

00:55:01 that science is fun.

00:55:03 Thank you very much.

00:55:06 You can do some of these experiments at home.

00:55:10 Check out the Science is Fun website.

00:55:35 Science is Fun

00:56:06 Science is Fun

00:56:23 To order a VHS copy of this program,

00:56:25 please send a check for $30 to

00:56:28 1996 UW Christmas Lecture, Department of Chemistry,

00:56:32 University of Wisconsin, Madison, Wisconsin, 53706.

00:56:37 Please do not send cash.

00:56:39 Credit card and COD orders cannot be accepted.