Wisconsin Public Television University Place Science is Fun  Summer Chemistry Extravaganza Bassam Shakhashiri  June 25, 2012 UP737   cc § §  >> He's more talented than I am. [laughter] § §  Do you know what? >> What? >> I'm ready to start, are you? >> Yeah. >> All right, let's all get started then. § § Thank you, Todd. [applause]  We're happy to see you here, all smiles, and we're going to have a good time. When we do science experiments you know that we always obey the safety rules. That's why you noticed, and if you haven't I'm going to point it out to you now, I have my goggles on. You see that, right? That's required by the state law. I'm a law abiding citizen, and everyone who does science experiments should obey the safety rules. So, we obey the safety rules. 

We have fun, and you know what? If you pay attention, I promise you, you'll have a good time. I'd like you to sit back and relax, and pay close attention. Pay close attention by watching what's going on, by listening to what's going on. Listening to what's going on, listening to my voice, listening to the others as we go alone. I'm going to start the experiments by striking a match. Big deal. You came all the way here to see Dr. Shakhashiri strike a match, right? Right. Well, this is an example of what we call a combustion reaction. This combustion reaction is-- It's going to go out now because I blew it out. I need to connect this to a source of fuel. 

We have to burn fuel in order to produce a combustion reaction. Combustion is when something combines with oxygen, usually in the air, but not always. And we have-- Okay, do you see this flame now? What color is the flame? [audience answers] >> And, let's see, can we make the flame bigger?  What other colors do you see? [audience answers] Do I have to ask all the questions? [laughter] You each ask a lot of questions, and you each pay close attention to what goes on. Because if you don't, you're going to miss out on a lot of interesting things that are going on. So, this is an example of what we call a controlled combustion reaction. What's burning here is fuel. The fuel is a gas called natural gas. It's methane. Methane is the major component of natural gas. What I'm going to do now is turn off the gas, like this, we'll come back to that burner. 

I'm going to connect a different burner back here.  You know what you're doing though, you trust me telling you what's going on here, right? I'm going to connect this and I'm going to turn the gas on. I have to strike a match because I want to turn on a different burner. Okay, here we go.  All right, that got your attention now, right? [laughter] What color is this flame? >> Yellow. >> Is it all yellow-orange, or is there some other coloration? >> Blue. >> Blue. The next time you look at a candle flame, or a match flame, or any flame, look carefully. You will almost always see a blue coloration at the bottom of the flame. One of the questions we like to try to find answers to is how come the color is blue at the bottom of the flame. 

We put this down here. It's an example of a controlled combustion reaction. Now you know in my lab we do a lot of fun experiments. As I said, you've got to pay attention, because if you don't, you're going to miss out on a lot of fun things. You help me out now a little bit. What do you see we have up in the air? >> Balloons. >> How many balloons are there? >> Six. >> And what color are they? >> Red, yellow and green. >> So you told me that there are six balloons and each one of them is red, green and yellow. Is that what you said? Come on, you can do better than that, okay? How many balloons are up there? >> Six! >> And what colors are the balloons? [all talking at once] I love that sound. 

Mumble, mumble, mumble. Do you know why? Because each one of us is free to express our observations in any way we choose to. I can ask you a question and get the same answer from all of you. How many balloons are there? >> Six. >> But when I say, what colors are they, then some of you start to-- You start at different ends, okay? These balloons, are they big balloons or small balloons? [talking at once] How big, how medium? How big is big? Are they about the size of somebody's head? >> Yes. >> Somebody who has a big head. [laughter] What do you suppose we have in those balloons? >> Helium! >> Why do you say helium? Because you know from experience that helium-filled balloons are lighter than air. That's a key word, experience. We learn things so that, we not only store the information in our memory banks, but we use the information. We make connections between what we know and what we are observing. 

I'm going to try to tell you now what I will do, and you will watch it. I'm going to take this flame, you know what color it is, right? And I'm going to try to put the flame to this balloon right here. Some of you are covering your ears. [laughter] Why are you covering your ears? Because you know from experience, right? That is the connection that you made. You know from experience there might be a pop sound. So here we go. Let's find out what's in this balloon. [popping sound] [audience exclaims] That balloon had in it the gas helium, and helium is a gas that does not burn. That balloon had in it the gas helium, and helium does not burn. What we always do in science is repeat the experiment. 

So I'm going to now reach for the second balloon. What color is it? >> Green. >> Let's see what happens now. [popping sound] Did the same thing happen? [talking at once] >> Exactly the same thing? >> No! >> What was different? [talking at once] The flame didn't go out, right, this time, the second time. That's why we repeat the experiment, in order to find out what observations we make, and what kind of sense we can make out of these observations. Okay, so now we have-- What color balloons are next? >> Yellow. >> Let's try to find out what's in those balloons by doing the same experiment. Here we go! Ready? [explosion] [audience exclaims] [applause]  Did that balloon have in it the gas helium? >> No! >> That balloon had in it a gas lighter than air, but a gas that combines with oxygen in the air, in an uncontrolled combustion reaction. Do you know what we call uncontrolled combustion reactions? >> Explosions. >> Explosions. 

An explosion is an uncontrolled combustion reaction. So, what we want to do next is what we always do in science. Repeat the experiment. But this time, we're going to repeat the experiment in the dark. You ready? Here we go! [explosion] [audience exclaims] [applause]  Did you see that ball of fire? >> Yeah! >> Did you see it better with the lights on or with the lights out? >> Out. >> That's something we always have to keep in mind when we're making observations, about light, about emission of light. We do the experiments in the dark, we don't do it outside in the sunlight because we cannot see the experiment as well. So we keep that in mind, all right? All right, we have lots of things on the lecture table over here. We also have some more balloons. Shall we do more balloons or different experiments? >> Balloons! >> More balloons? Okay, more balloons. 

We'll do more balloons. What color are those balloons? >> Red. >> All right, you notice that when we went from helium to hydrogen, there was a difference in the amount of sound energy that was released, right? That's why before I do the next experiment, I want each one of you to obey the safety rules by protecting your eardrums from potential damage. What you do is you take both fingers like this, you stick them in your ears, okay, very tightly. I can't do that and do the experiment at the same time, so I have my ear protection right here. Okay, so, if you can hear the sound of my voice-- Can you hear the sound of my voice? [audience answers] That means you don't have your ears well protected, all right? I don't want you to be able to hear the sound of my voice because here we go. We try this experiment now. And we bring this, and-- [loud explosion] [audience exclaims] [laughter and applause]  That balloon had in it a mixture of hydrogen gas and oxygen gas. You know, air is a mixture of nitrogen and oxygen gases. But air has about 20% oxygen. 

In that balloon, we had more than 20% oxygen. That's why you could see and you could hear a different kind of reaction. What do we always do in science? >> Repeat! >> Repeat the experiment. Okay, here we go.  Are you ready? You're sure you're ready? [loud explosion] [audience exclaims] [applause]  Science. It's part of having fun with science. What does my t-shirt say? >> Science is fun. >> Oh, come on, you can do better than that. What does my t-shirt say? >> Science is fun! >> Okay, now you got it. Science is fun. 

Science is fun if you obey the safety rules, and you do experiments that you can learn from. So, I want to do another experiment here. You know, when we burn something that has carbon in it, we get carbon dioxide gas. Carbon dioxide is a gas that has no smell and no color, so we can't see it. But I'm going to do an experiment now with a different form of carbon dioxide. It's a solid form. It's called dry ice. Dry ice is solid carbon dioxide. It's very, very cold. It's temperature is minus 78 degrees Celsius. 

In science, we use the Celsius scale for temperature. I want everybody-- I have a little problem here. You see what my problem is? [laughter] What are you laughing at? Right, why are you laughing? What, what?! But you know what? Because we are always well prepared, I have another pair right here. Oops, same thing. Same thing. How about over here? That should do it. All right. So, this is solid carbon dioxide. I'll put it right here, a chunk of solid carbon dioxide. The temperature is minus 78 degrees Celsius. 

And everyone in the audience, not only the youngsters, but the adults, should be able to convert from degrees Fahrenheit to degrees Celsius, and vice versa. If you don't know how to do that, you can ask somebody. [laughter] I know, you can look it up on the Internet, which is okay, too. But it's better to ask somebody, because you can have a conversation with another person. You can't have a conversation with the Internet, can you? Sometimes you listen to things on the Internet, but you can't talk back to the Internet, right? So, do things together. There is dry ice. It changes from being a solid to a gas directly without melting, by a process we call sublimation. Sublimation is happening right now, but we can't see it. How come we can't see it? Because carbon dioxide gas is invisible. It has no color. 

It has no smell. So, what's happening right here is called sublimation. Can you say sublimation? >> Sublimation. >> Okay, sublimation. You've learned a new word if you didn't know it before. Maybe you can spell it correctly, because in communicating science, we have to be careful about the words and sentences we use, so that we are correct in using them. So, I would like you to focus your attention on this part. What do you see between my two hands here? What shape are they? [audience answers] >> And how many of them are there? >> Six. >> Do I always have to ask all the questions? And what colors do you see? [audience answers] There's that mumble, mumble again, right? I love that sound. Any adults in the audience? You should respect the youngsters. 

Let them express themselves any way they want to! [laughter] As long as we do things safely, all right? So, we have six glass cylinders. How do we know they're glass? We take metal and we-- [taps glass cylinders] Tap them. We know from experience what glass sounds like, right? There's a connection that you have made, right? All right, and these seem to be arranged in some kind of order. What's the order? It's the order of the color inside each of the cylinders. They're arranged in pairs, right? This pair is what color? >> Pink. >> This pair? >> Purple. >> And this pair? >> Blue. >> All right. What I'm going to do now, you watch carefully what I'm going to do now, okay? I'm going to pull this one. I'm not saying what I'm doing, you're watching what I'm doing. 

 What am I doing? [audience answers]  Okay, how many cylinders are there now? [laughter] Still the same, right? They're arranged in pairs. This pair is what color? >> Blue. >> This one? >> Pink. >> This one? >> Purple. >> All right, now I want you to do the very same thing I ask my students in my chemistry class in this room. In order to sharpen your powers of observation, I want you to pretend to be the play-by-play radio announcer describing to someone who's not with us what's going on. Not the TV announcer. That person has got it made, because the picture tells almost everything, right? Okay, so you're doing the play-by-play radio announcing, describing to someone who's not with us, a friend, or a parent, or someone, your neighbor, what's going on. So, we have, what do we have? [audience answers] And they're arranged in order of the color of what's in the liquid, of what's in the cylinders. And what's in the cylinders are colored liquids. 

How do we know they're liquids? We shake them up, and we know from experience what liquids do when they're shaken up, right? So here's the experiment. I take chunks of dry ice and I put them in the cylinders. Did I put the dry ice in every cylinder? >> No. >> What did I do? You're doing my description. [audience talking] Every other cylinder. Is there anything interesting happening? [audience exclaims]  All kinds of interesting things are happening, right? Why are they happening? Because I mixed chemicals with each other, right? I mixed the dry ice with the liquids in the cylinders. Not in every cylinder, but in every other cylinder. Why do you suppose I did that? [audience answers] So you can make a comparison between what the color was before the experiment and the color after the experiment. So, you see bubbles. What kind of bubbles are those? >> Carbon dioxide. 

>> They're carbon dioxide bubbles. Where are they coming from? >> Dry ice. >> The sublimation of the dry ice, that's where they're coming from, right? Right here, dry ice is subliming, too. Right here, but we can't see it because gas is mixing with gas. Over here, gas is mixing with? >> Liquid. >> Liquid, right? You make observations and try to make sense out of these observations. All right, in this pair, where I put the dry ice, the color of the liquid changed from? >> Blue. >> How about in this pair? >> Pink. >> To what? >> Clear. >> Clear? This is a clear and colored liquid. 

This is a clear and colored liquid. This is clear and? >> Colorless. >> Colorless, okay. No one is going to confuse the words clear and colorless after now, right? All right, how about in this pair? The color changed from? >> Purple. >> All right, now you watch carefully anything you want to watch, but if you want to follow my experiment, focus your attention on this cylinder right here. This one here, the fifth cylinder from the left. Did I say that correctly? The fifth cylinder from the left. Whose left? >> Ours. >> The fifth cylinder from? You always have to make that observation, right? Okay, so I'm going to take chunks of dry ice and put them in there. You watch this one and tell me how many different color changes you see. 

You can count them out loud. [audience counting and talking]  We know what the overall color change is going to be on this one, right? Are we there yet? >> No. >> We also have to be patient when we do scientific experiments, all right. So, we can add a little more and see what happens. These are two experiments that have to do with combustion and with the product of combustion, if something has carbon in it, like natural gas. Methane has carbon in it. All gasoline has carbon in it, so we get a lot of carbon dioxide. This is an experiment with solid carbon dioxide. Okay, I want to do now an experiment. This has all been exciting. 

Has this been good? Did you like this experiment? [applause] All right. Now, I want to do another experiment, but I kind of lost my directions here. But I brought my book with me here. This is a book that I wrote, "Chemical Demonstrations." Bassam Shakhashiri, right here. So with your permission, I'm going to open the book and read the instructions for this experiment. Okay, here we go. Just be patient with me. Whoops! This is not an ordinary book. This is a hot book! [laughter] Actually, it's not a book at all. It's just a book cover. 

I wish I had a camera to catch the expressions on your faces here. [laughter] The jaws just dropped down. So, I'll show you what this book cover has on the inside. On the inside, I have two batteries. And I have the filament of a light bulb right up here. Then I have a flint that I soaked with lighter fluid when you weren't looking. You weren't looking, okay. There's something else that I'm going to show you if you haven't seen before. Down here, there's a small what? [audience answers] What color is it? >> Red! >> You can see it, right? All right. So, batteries have stored in them chemical energy. 

When I push the button, which I haven't done yet, the chemical energy changes into electrical energy and the filament lights up. But this filament, like all other filaments in all light bulbs is not 100% efficient. It gives off light energy and also? >> Heat. >> Heat. Then that ignites the fuel that the flint is soaked in. So here we go. Notice what I do. I move it away from my face. You know why, right? You know why. I push the button and there it is. 

So now you tell me what happens when I close the book. What happened when I close the book? [audience answers] You know, in order to have a fire you need three things. You need something that burns. We talked about that before, right? You need oxygen, usually from the air. And you also need heat. You need a source of ignition. So when I close the book, what happened? The flame went out, right? But there's still a lot of oxygen, because I open the book and there's oxygen, but there's no flame. How come? What's missing? Heat. How do I get the heat going? >> Push the button. >> Stop talking and push the button, right? That's what I should do, right? Okay, I push the button right there. 

Okay, you see it? We teach about the fire triangle to help people learn how to put out fires, not to start fires. Okay, so these are examples of combustion reactions. Now I'm going to go back and connect my first burner to the gas outlet, and I'm going to light this burner. You see that these different burners have different shapes and give off different flames, and of course, they have different-- Here is a piece of steel wool. You all know about steel wool, right? You use it at home, right? It's made of iron with a little bit of carbon in it, and that's what makes it steel. If I put this in the flame, watch and see what happens. See? It burns. Okay? There's 20% oxygen in the air. This flask right here has some sand at the bottom and some glass beads, but also has in it oxygen gas, which is invisible, we can't see it. Watch what happens when I take this and I put more-- I want you all over there to see this and to see what happens when I put this in there. 

[audience "oohs"] The more oxygen, the brighter the combustion reaction. You can see all the steel wool has disintegrated. So that's an example of the combustion of iron. To show you now the different types of elements and materials, not only elements that are in the periodic table, but different materials undergo combustion. I would like you to welcome our lecture demonstrator, Jim Maynard. [applause] >> Hi, everybody. >> What do you have, Jim? >> Today we've been burning a lot of different things, so now I'm going to try to burn a different element. We saw iron burn and we've seen natural gas burn. I'm going to try to burn carbon. >> Carbon, I already burned carbon. 

>> You burned something that had carbon in it. >> This has carbon in it. This is a piece of paper, right there. >> That's very nice. Love that. >> But not nice enough for you? >> Well, I mean, it's a start. I'm going to try and do a little more burning. >> What is this? A new experiment that you want to show me? >> It is sort of a new experiment for you. >> Do you think it's safe to show it to them too? >> I hope so. >> You hope so? >> It's going to be fine. 

First things first, we're going to take and heat up a piece of carbon. I have a piece here a piece of carbon. >> Can you show me the carbon? >> A very small piece of carbon. It's part of a carbon electrode. This is from my lab. We're going to use a part of this carbon electrode because it's very porous, so I can warm it up rather well. So I'm going to do that. I'm going to start by turning on my propane torch. This is another form of gas we can use. I'm going to heat this up. 

You'll notice that any time something gets hot, a lot of times it will get warm enough to give off a color that's not the same color that is was before it was hot. This is called the Boltzmann Theory. The hotter something gets, the brighter it gets, and the closer to white it gets, in many cases, in the scale of light. White is hotter than, say, yellow or maybe red. >> How hot do you want it to be? >> I want it to be good and glowing hot. I want it to be nice and hot, so when I put this on here-- >> You want to carbon to be glowing, not the flame. I see it glowing now. >> See? We want to warm the carbon up so it's really warm. Then once we get it going in here. >> What's in there? >> This has oxygen in it just like your flask over there, but I'm going to feed mine in a little bit. 

Here we go. We're going to drop this in here, and we're going to let this down. We're going to see if it burns. Then I'm going to turn the lights off, because it's always better to see things that give off light when they are in the dark. I'm going to turn up my gas a little bit. >> You're going to blow some oxygen from the tank? >> That's right. I'm blowing oxygen from the tank into this little piece of carbon here. You can see it's getting brighter. There, it caught on fire. >> Yup. 

>> So this is what happens sometimes when a combustion reaction goes out of control at a place like, say, a nuclear power plant, where they use graphite in ways to control how many neutrons end up hitting the fuel. That's what this experiment was sort of based on. We wanted to be able to see if we could make carbon burn in a safe, sort of a laboratory, way. As you can see, we've made some progress. >> So what do you get when you burn carbon like this? >> Just carbon dioxide. >> We can't see the carbon dioxide because it's invisible, right, and has no color. >> Right, it's an invisible gas that we can't see. There's just a teeny, tiny layer of carbon that you'll eventually see. It looks so thin that it looks white. >> This is a new experiment. 

I like it, Jim. >> Thank you very much. >> Thank you, Jim. Thanks a lot. >> Thanks. [applause] What I'm going to show you next is a mixture of rust and aluminum. This is a metallic mixture, right? Iron oxide and aluminum inside this flower pot that's sitting inside another flower pot. What I have inside that box is the very same mixture, but I'm going to use a different sparkler. I'm going to use this sparkler, and you pay close attention now to what we're going to do here. I'm going to get this going. 

When it's hot and going, I'm going to stick it right into the mixture of iron oxide, rust, and aluminum. But not right here. In the box. Here we go.  And with the lights down. [audience exclaims]  Did you see that molten stream  coming down from the bottom of the flower pot? Do you know what that was? That was molten iron, element number 26, melted. This reaction gives off a lot of heat. It is what we call a highly exothermic reaction. Can you say exothermic? >> Exothermic. >> Exothermic is what we saw over there. 

I want to show you also a little bit of what is at the bottom here.  This is-- See how hot that is? Right? When it came down it was almost white hot, right? Right now it's red hot. There's a bucket of sand there that we use to catch the molten iron. Those are examples of combustion reactions. Metals are used to produce beautiful sound. That's why I'd like you to meet right now, Todd Hamish. Todd. [applause]  >> I'm about to play a piece that I wrote for this gentleman here on his 42nd anniversary of his TV show. It's called Molybdenum. If you look at the number 42 above me, you'll see why. 

>> I see it. § § >> Does that sound like Molybdenum? >> Why not? [laughter] § § >> Good? >> Yeah, very good. § §  [applause] Very nice.  Very nice, Todd. >> Thank you very much. >> All you were doing was striking the molybdenum. What is that material over there? >> This is the skin of a goat. >> A goat? Okay. Metals and skin. What do you call these thing? >> Mallets. 

>> Mallets, okay. What are they made of? >> This is made out of wood. >> So when you strike it it produces a sound. >> If I was a scientist I would say it creates a vibration in the air. >> You are a scientist. A vibration in the air, okay. >> That's right, a sound. >> So you mean, like you and I are talking right now, our vocal cords are vibrating and pushing the air. >> Correct. >> And making some sound. 

>> Yes. >> Or some noise, as the case might be, right? That's noise. >> Yes. >> But a talented person like you can do something better than noise. >> Hopefully. >> Hopefully? Let's see that one more time. § §  Very nice. That is very nice. [applause] Let's see, you and Dr. Schreiner have been working with some experiments that are kind of new to me. Rodney are you ready to show us your experiment? >> Yes, speaking of molybdenum. 

>> Yes. >> I have for you the real thing. A piece of molybdenum. >> Oh, it's heavy. >> Yes, it is rather heavy. Just for comparison purposes, I have a piece of aluminum exactly the same size. >> That's aluminum, number 13. And molybdenum is number 42. The molybdenum is a lot heavier. >> It's about four times as heavy. 

>> That's very nice that you give me this on the 42nd anniversary of our program >> He's been doing these for 42 years, isn't that amazing? [applause] >> And Rodney has been doing them with me for 41 years. So give him a hand too! [applause] All right Rod, what about these now? >> For one thing, they look a lot alike, don't they? >> Yeah. >> You can't tell that one of them is a lot lighter than the other one, but I have something I can show you, and you will able to tell that are quite different. I need a piece of apparatus down here. Something like that. Let's see. Here it is. I have a little stand. >> What kind of a stand is this? What's it made of? >> It's a piece of wood with two green ropes glued onto it. >> It's painted. 

>> The wood is painted black. >> That's the play by play description. >> It's not ebony, it's just oak painted black. >> All right. >> And two pieces of green rope. There's the aluminum, and there's the molybdenum, and one more piece. >> The aluminum is on the right or on the left? >> This is the aluminum. Where is it? >> The right. >> On the right. >> Who's right? >> Their right. 

>> Okay. >> This is my left. Okay, aluminum. § § Molybdenum. § [higher pitched tone] § >> They sound different. >> They sound different, don't they? >> Yeah. >> Well, that got me interested in what's going on here. So I put together a whole bunch of other pieces of metal. This one looks different. What do you think that is? >> Copper. 

>> That's exactly right, it's copper. Here's copper. [makes tapping sound] >> It's like a dud. >> We'll have to move it a bit. [makes tapping sound] Maybe if I turn it over. [makes tapping sound] Do you have a better mallet? § § There we go. Yes, you need a hard mallet. § § Professionals are definitely better at these things. [laughter] § § Okay. Let's see. 

Here we have some iron. Iron is kind of gray like the others, like the other two metals. Aluminum, molybdenum, iron. >> They all sound different. >> Slightly different. This is steel, which is an alloy of the iron. § §  And another alloy, what's that? >> Gold. >> Gold? Oh! I think I'm going to leave. [laughter] >> No, no, no. >> It may look like gold, but there is an alloy that looks like gold. 

It's brass. It's an alloy of copper and zinc. So, let's go. >> All right. >> It looks different. § §  >> Not bad, huh? >> I like my tune. § §  >> You've constructed an instrument here. What do you call this? >> A metalophone. >> A metalophone. >> Or Todd has a tubophone, and I have, maybe, a barophone. 

Mine are made of bars. Mine's different from Todd's. In Todd's, all of the tubes are the same metal but they're different sizes. My instrument, everything is the same size, but they're made of different metals. § §  >> That's pretty good. All right Rod, we'll put those away. I like this experiment too. I like that, yeah. Let's see. What is that? >> This is my third favorite instrument in the world. 

>> Your third favorite? >> Yes. >> You're trusting me with it? >> Yes. >> What do I do with it? >> You hit it with this. I hit it with this, he says. >> Yes. >> But I don't have to be touching it, right? >> Correct. >> What is this called? >> A triangle. >> Can you play the triangle? I can play the triangle. Listen to this. § § [applause and laughter]  >> That's beautiful. 

>> That's a bigger triangle. >> This is a Brazilian Triangle. Do you know how many are in a Brazilian? >> No. >> It's a bad joke, I don't know. There's no answer. >> All right, all right. >> Sorry. § §  >> He knows what he's doing, right? § §  I'm beginning to get it, right? § §  How about you play this? >> Oh, yeah. [applause]  >> All done with metals. >> I play in the symphony orchestra, as you know. 

>> Yes, I know that. >> And a lot of times I get to stand in the back. There's a lady with a harp, and she plays this big glissando thing. Then when she hits her very top string, I get to do this. But in a tuxedo. So imagine the bowtie. >> Yes, yes, yes. >> She plays her glissando and I'm waiting, waiting, waiting-- § [taps triangle once] § [laughter and applause]  >> So, if I put my tuxedo on, I could do the same thing, right? >> Yes. >> But you can do more than that. >> Yes. 

All right, all right, all right. § §  >> Sounds good. [applause] Your third favorite. What do we have here? We have a fish tank, but there's no fish in it. There's water in it. >> Is that water? >> Yeah, it's water. >> Okay, good. >> It's not to drink though. It's to do experiments with. Do you want to do an experiment with this? >> Yeah. 

>> What? >> I was going to get my triangle wet and see what happens. >> You're going to wet your triangle? >> Yeah. >> Okay. § § § [triangle note warps lower] §  It's not only because it's wet, it's because it's submerged in the liquid, in the water, right? >> Right, yeah. § [modulating pitch] § >> Very interesting. Sound waves travel differently in the air than they do in-- >> Water. >> You knew that, right? But he has a beautiful way of showing us. Play something in the air and then play it in the water. § § § [lower pitch] § They are different. Do you have any other instrument that we can try with the water? >> Sure. 

How about this? >> What is this? >> That's a pot lid from my old pots. Pots and pans. >> That's it. >> Do you want to try? >> I want to try this, yeah. >> What if you hold it like this so we can dip it. Hold it like that. >> Okay. >> Here, I'll hold. You hit, I'll hold. § § § [lower pitch] § >> Once again, sound waves travel differently depending on the medium that you have, right? § § Very good, all right. 

>> Notice it changes by how deep in the water it goes. >> I didn't notice that. Let's try that again. You do it. >> The pitch will go up and down. The pitch is the high and lowness of the sound. § [pitch gets lower] § § [pitch gets higher] § Cool. >> I hope you try this at home. [applause] >> Do you have anything bigger than that? You do! You're prepared.  Oh, my! That's bigger. 

[laughter] >> Catch me if I fall. >> Are you going to take a dive, or what? >> All right, so this is a what? >> A gong. >> Very nice. § [loud resonating tones] §  § [tone goes lower then higher] § [laughter] § § § [pitch goes lower] § § [pitch goes higher] § § § Sorry I got your book wet. >> That's okay. § §  Very nice. All right, thank you, Todd. [applause]  I see you have some other instruments back there. What else do you have there? I see you have a drum of some sort. We've had heat energy, light energy, sound energy, right? Lots of different forms of energy. 

Let's see what you can do with that drum. >> I have your drum. >> That's my drum, you're right. What are you going to do with it? >> Let's see, I need a candle. There's some right here. >> How many candles do we have? Three candles here. >> Yeah, I want to try this with two different drums. I'll bet I can blow out the candle with the drum. >> You can't blow them out, they're already blown out. >> Okay, would you please light the candles. 

>> Okay, you want me to light the candles, so you can blow them out with the drum? >> Yes. >> Like with a drum beat? >> One beat. >> One beat? >> Okay. >> Is it going to be loud? >> No, it will be this sound. [taps drum] >> You're kidding me.  >> Okay. [taps drum] >> That's out! We always like to, in science, repeat the experiment, right? >> Let's see. [taps drum] >> All right. You got two of them. Very nice. 

Very good. [applause] Now, there were some other experiments that you and Jim and Rodney were trying. Jim, are you ready with your experiment?  What do you have there, Jim? A bicycle horn. [horn squeeking] >> Hi. I was feeling sort of left out.  >> What do you have in here? >> I have some gas in here, a lighter than air gas. In this case, it's helium. Okay, so helium gas floats in air. I have the balloon and I have a horn. How does a horn work? >> You push the bulb and the sound comes out. 

>> Why? What's going through it? >> You're generating a vibration. >> Air is going through it. >> Air, you're vibrating the air. >> Air is one kind of gas, and then this is helium. It's another kind of gas. >> It's lighter. >> It's lighter than air. My experiment is I'm going to take this and I'm going to honk it in here, and see what we get. All right, I'm going to open my big, fancy balloon here. Okay. 

Ready? [pitch higher] >> Take it out. Let me see. That's a trick. >> It must be broken. >> Do it now.  Let me try it. >> Maybe it's just you. >> Where is it?  Again the medium make a difference about the vibration that's being generated. >> It does. Wait a minute. 

>> What? >> Let's try something else. We found out that the vibrations that were caused by this different in the other gas. Let's see if it works for bells. >> All right. >> All right. The hard part is the gas does not want to stay in the balloon, or in the bag in this case. It's in the bag, but just barely. [bells rings softer] >> You're not shaking it hard enough. Yes, you are. [laughter] >> Yup, so let's try out here again. 

The sound must travel better in the heavier gas. That's what I have for today. Thank you. [applause]  >> Rodney, do you have some more experiments? Are you ready with some more experiments? >> I have a few things, yes. While I was out shopping for me pieces of metal for the metalophone I stopped in a toy store and I got these whistles. I'm on a noise-maker kick, I guess.  It's kind of like that horn that Jim just showed us, but it has a much higher pitch because it's a lot smaller.  Yes, ouch. But then, next door to the toy store there was a hardware store and I bought one of these. It's a PVC pipe. 

Exactly right. And luckily, the whistle just fits into the end of the PVC pipe. It fits better if I hold it, so I will hold it in place. Let's see what happens. [pitch sounds lower] >> Same whistle? You're blowing harder. >> Well-- >> It's different. >> Let's see what I can do. If I blow not-quite-so-hard on the whistle--  It doesn't make much noise but if I blow not-so-hard when it's in the pipe--  If I blow very softly-- [soft tone] If I blow a little harder-- [higher pitch] A little harder still. [higher pitch] Or harder yet. [higher pitch] §§ >> Okay. 

[applause] All right.  >> You know what that reminded me of? That reminded me I need to go back to the toy store and get some of these. You've all played with these, right? >> What do you do with those? >> They're called Twirly Tubes, and not for nothing are they called Twirly Tubes. Because you twirl them.  >> Nothing happened. >> Nothing happens.  [surprised exclamation]  >> He has a cork in there. >> I have a cork in the end.  If I take the cork out. [high pitched sound] What does that show? >> It shows that air was passing through. 

>> That air has to go through this tube in order for it to make noise. Maybe you didn't already know that.  It I put the cork in the end-- nothing. >> So you need the air to move. >> The air has to move through it. And just as with my whistle and pipe, the faster the air moves through it, the higher the pitch.  I've also discovered something else that effects the pitch. That is-- >> Length. >> Length. If you have a tube which is a slightly different length, it will sound a bit different. 

>> And different color. >> That might be. >> I notice things. >> Yes, yes.  There's a cork in this one? There we go. >> It's shorter. >> It's shorter and I have to spin it faster to get the air to go through.  They're slightly different pitches. What happens to the pitch if it gets even shorter? >> The red is the shortest? >> The red is the shortest one. Here, Todd. 

>> So these are color-coded just to tell us something about the length. >> Yes. >> Mine is multicolored. >> That's because you get to do everything. §§  [applause]  >> Thank you, Rod.  Todd, you've had this cover here. Do you have something under the cover there? >> Yes. >> What is it? >> This is a xylophone. >> A xylophone, that's where we started. >> That is where we started. 

>> Why did you have it covered? >> Because you keep burning things and making things explode. >> Yes, and you wanted to protect this. >> Yes. >> That's the reason. >> Yes. >> But why did you want to protect it? I mean, why did you bring it here? >> Because I like to play it. And I like to play it for nice people. >> Please do. >> Okay.  §§  >> Very nice, Todd. 

[applause]  So Todd, you play in the symphony, you play the xylophone, you're also a teacher. >> Yes, sir. >> Do you like teaching? >> Yes, sir. >> I like teaching too. >> I can tell. >> I'm going to show you an experiment here. I'm going to show everyone the same experiment. I have a glass beaker. I can make sound with this glass beaker too, but not as beautiful as you do. By the way, when I tap it here it sounds different than here, right? All right. 

We have to think about that. We always think about what we observe. This is a glass beaker. It is empty except for air. I'm going to put it on top of this stirrer right here. I'm going to turn the light on so you can see it a little bit better. I want everybody to look at this beaker. Todd, you look at this beaker right now. I know, cover it up first. This beaker has a volume of four liters. 

If you look at it right now, you just learned how big four liters is. You cannot unlearn it. You may forget it. That's different. I'm going to take a magnet coated with Teflon, put it in there and I'm going to turn the switch on. Can you see the magnet spin? Is it spinning in a clockwise direction or a counter clockwise direction? As we look down at it, it's spinning in a clockwise direction, right? I want you, Todd, and everyone else, to visualize this magnet, spinning in this way. This way which we call clockwise. But instead of looking down at it, you're looking up at it. Tell me what direction you see when you're looking up at it. >> Counter clockwise. 

>> Counter clockwise? You're getting me confused. Is this my right hand or my left hand? >> Right. >> I'm looking up at it. Now I put it down and I look down at it. Is it my right hand or my left hand? >> Right. >> It's still my right hand, right? What's going on here? We have to think about it, okay? We have to think about it. Todd, and everyone else, I want you to stick your finger out like this right now. I want everyone to rotate your finger in a clockwise direction. Hey! I said clockwise. What are you doing? I said clockwise. 

I'm doing it clockwise. Watch me. See? When I turn around I'm doing it the same way you're doing it. But when I go back this way, what do you see me moving in? >> Counter clockwise. >> All right, you get the point. So, Todd, I'm going to take three clear and colorless liquids and put them in there. Here's the first one. I'm going to increase the mixing a little bit. There it is. That's getting a little bit cloudy. 

Here's a second liquid. Mix it a little faster. What do you see now? >> A vortex. >> It looks like a tornado. I hope this is the only tornado you'll ever see. We don't want real tornados around us here. I add the third one. Three clear and colorless liquids and we get a very beautiful blue color. I turned it too fast. Too fast. 

It's blue again. And now it's white. Now it's what? >> Orange. >> You've go to pay attention to what's going on. Don't look over here. Look over there. Always pay attention to what's going on. This is a chemical oscillating reaction. It is one of about 50 know such reactions. It's one of my favorite experiments, for two reasons. 

One, it was discovered by two high school teachers. It's named after them, Todd. It's called the Briggs-Rauscher reaction. Briggs and Rauscher taught high school physics and chemistry in northern California. They published a paper in 1973 describing this beautiful, captivating behavior that we're looking at right now. If you're looking over here you're captivated, right? If you're looking some place else, you're not. The second reason it's special to me, it's one of my favorites, is because it took scientists, high-powered scientists, members of the National Academy of Science, it took them nine years to figure out what's going on here. When we see something fascinating we ask questions, we pay attention, we become vigilant, we be patient and try to understand what it is that is going on in the system. This is the Briggs-Rauscher chemical oscillating reaction. What I'd like to do now is call your attention to this device right here. 

I have a funnel and a spiral made of glass, and I have a beaker at the bottom. Is this beaker four liters in size? >> No. >> It's smaller than that, right? What I'm going to do is take a clear and colored liquid and mix it with a clear and colorless liquid. I'm going to do this in the dark. If somebody would turn the lights down. There we go. Here we go. [exclamations] This is the release of energy in the form of light, but not in the form of heat, nor in the form of sound. The lights up. please. 

This is like the firefly reaction. This is chemiluminescence. Can you say chemiluminescence? >> Chemiluminescence. >> And before you go to sleep tonight, learn how to spell chemiluminescence. Because that's how we train ourselves to enjoy what it is that we do. Let me turn the lights up a little more here. This is the release of energy in the form of light, as it is over here, as it is in that device at the other end there. These are called light-emitting diodes. Different transformations than the ones we see over here. To do our next experiment I'm going to light this burner. 

I'm going to show you something that is really of interest, not only to me, but to all. Here we go. I'm going to turn this light off. I'm going to take these spray bottles and I'm going to spray different liquids into this flame. What color is flame? >> Blue. >> What color did you say it is? >> Green. >> What color is it now? >> Blue. >> And then right now? >> Green. >> How about if I take this one? >> Red. >> How about we do this in the dark. 

Can you push the bottom over there somebody. Okay. here we go. How about we do them together, like that. With the lights on, please. You saw what happened? >> Yeah. >> The liquids are called methyl alcohol, and they have in them dissolved metal salts that produce different colors. The very same colors that we see up in the sky when the firework has in it lithium. So when you see red on Independence Day, or any other time there's fireworks, you can say, lithium. You can say, oh, ah, that's okay, but also say, lithium. 

If you see this color then that is sodium. That's table salt. Table salt is dissolved in there. You'll notice if I spray to much then it hit the table top with you saw the flame there in the dark, right? Let's see what we have here. What color do we have? With the lights out. Lights out. This is what color? Do you see blue? >> Purple. >> Purple, yeah. That's potassium Let me see what else I have here. I see it, thank you. 

[exclamations] This is stranchium. This one is lithium. This is stranchium. Okay, let me see what I'm doing with the lights on here, Jim. Safety comes first. Okay. This one is barium. Actually, copper also produces that color. I like doing them together. Do you like this experiment? I like this experiment too. 

[applause]  Now, none other then Jim Maynard is going to come out and do one more experiment that has sound in it as well, right? >> Yup. I'm going to make a spot up here. >> We're going to get this out of the way. >> Yup. >> Don't you like my chemiluminescence reaction, Jim? >> I love it. It's still glowing. >> It's still glowing, right. What do you have here? A long, glass tube. >> Oh, yes. >> It looks a little wet on the inside. 

>> It is. >> It is wet on the inside. >> A little bit, yeah. >> What else do you have in there? >> This is also fun of a gas. There's a little bit of water, and actually that's an artifact of how we fill the tank. The gas in here is actually called nitrous oxide, or laughing gas. It's the same kind of gas that you would get at the dentist if they were doing sleep dentistry. It's the same kind of gas you'd find in your whipped cream dispenser. One of the interesting this about it is that it, basically, likes to burn. It supports combustion, but it itself does not burn. 

We're going to mix it with another liquid called carbon disulfide. >> It looks clear and colorless to me. >> Yup. It's a clear and colorless liquid. >> Carbon disulfide. Is that kind of related to carbon dioxide? Carbon dioxide is with oxygen. Carbon disulfide is with sulfur. Right below oxygen on the periodic table. Okay, but it's a liquid. All right, Jim. >> Okay. 

>> Are you sure you're safe up there? >> Oh, I'm fine. >> You have a rubber stopper on top. >> I do. >> Why is that? >> Because the gas wants to get out. >> Okay, keep the gas in there then. >> At least until we use it. Now I'm going to draw this carbon disulfide-- >> You're going to put a little bit of this carbon disulfide into this long, glass tube that has in it-- >> Nitrous oxide. >> Nitrous oxide, N2O, laughing gas. >> Yup, laughing gas. We're going to put this in here, and the we're going to mix this. 

>> Okay, so more liquid in there. Now what are you going to do? >> Before I mix it I'm going to get my reactor ready. My scientific actuator, as I like to call it. You may call it a propane torch. >> Are you mixing the carbon disulfide with the nitrous oxide? Okay. >> All right. They are really good and mixed now. This is an experiment we what to do with the dark. >> Nothing exciting is happening so far, Jim. >> Oh, don't worry. 

>> I'm not worried. >> Ready? One, two, three. [exclamations and applause]  >> That also was chemiluminescence. The release of energy in the form of light, but we see the sulfur now on the inside of the tube. All right. Thank you, Jim. Now we get to this experiment. I have some plastic bottles with corks in the top and nails stuck on the side. I'm going to take my LED out and put it back in my pocket. We have three of them. 

This one is cut out so you can see that on the inside the nails are not touching. There's a cork here too. What I'm going to do is use a device that gives off sparks. It's called a Tesla coil. I'm going to show you this if somebody would turn the lights off. John, push the light button, please. Do you see that spark? Now with the lights back on I'm going to touch one of the nails and see if I can make the spark jump across the gap that separates the two nails, all right? Here we go. Ready? >> Whoa! >> There was a little bit of an alcohol in there and we had an example of an uncontrolled combustion reaction. All right? Here we go now. We have another one. 

Let me turn this off. We don't need this. Are you okay there, Todd? All right. Let's try the next one. Ready? Let's do this one in the dark. [loud pop] >> Whoa! >> All right, with the lights back up. How about this one? [audience reacts] Do you see the two nails? Okay? Are you ready for this? In the dark. [loud explosive pop] [exclamations] All right, with the lights on. [applause]  [audience laughs and exclaims]  Are you sure you want me to do this one? >> Yeah! >> You've been a very good audience. I want to thank you for coming. 

Of course, this evening I want you to have a very pleasant summer, and before we do our grand finale, I want you to give a very big round of applause to Todd and Rodney and Jim together. [applause and cheers]  And now, here's the sparker! Would you like me to aim it over there? No way. All right. Are you ready? Here we go. [loud explosive pop] All right. [cheers and applause]  Thank you all for coming. Happy Independence Day. Thank you very much. Thank you. Thank you. 

Always have fun doing safe experiments. Thank you very much. Thanks. Thank you.