cc  >> Ladies and gentlemen,  let me introduce to you,  our cosmic corraller,  the lunar lander,  the alien ambassador,  and our ETMC for the evening,  Professor Clint Sprott!  (whistling)  (crashing, explosion)  § §  >> Hey!  (applause)  Welcome to the Wonders of  Physics.  Now you know I wasn't really  traveling around through the  solar system in my rocket ship,  right?  But I did want to get you in the  mood to learn about  Physics of the Cosmos, because  the year 2009 is the  International Year of Astronomy,  celebrating its contributions  to society, and to culture.  It's also the 400th anniversary  of the first use of the  telescope by Galileo.  Here's a picture of me with  Galileo many years ago.  (laughter)  But you know, it didn't seem  quite right to just be  international celebration.  So we thought we would do  something a little bit different  this year.  Instead of my doing all the  demonstrations, as I've done for  many, many years, we thought  we'd invite visitors from some  of our neighboring planets to  come and tell you about physics  in their part of the solar  system.  And our first visitor is from  the planet Mars.  As you know, Mars is the fourth  planet in the solar system.  It's sometimes called the red  planet. 

 It's about half the size of the  earth, and it has about  one-third of earth's gravity.  And it also has very little  atmosphere.  Its atmosphere is only about one  percent as dense as the  atmosphere here on the earth,  and it's made up mainly of  carbon dioxide.  Now, Mars is the planet that's  the most studied.  It's the most like the earth.  It resembles the desert of  Arizona.  But it gets very cold there.  It reaches the temperature of  only about 20 degrees Fahrenheit  during the day.  And at night, it can get as cold  as 120 degrees below zero  Fahrenheit.  As you know, there are plans to  send humans to Mars. 

 We thought it would be good to  invite a Martian to come and  tell us what to expect when we  get there.  So, give a welcome to our  Martian visitor, Kukas Klukas.  (applause)  (grunting)  >> Ugh! Oh!  Professor Sprott, there's a  little problem.  The gravity here is way stronger  than I imagined.  I don't know if I can go on with  my presentation.  >> That could be a problem.  But I have a solution for you.  >> You do?  >> Yep, a balloon.  >> A balloon?  >> Let's just hook that to you  and see if that helps.  >> Okay, I'm willing to try it. 

 I think it's working.  But I'm kind of lopsided now.  >> We'll just give you a second  balloon.  >> Okay.  >> No problem.  How about that?  >> You know what?  I think that might actually  work.  Thank you, Professor Sprott.  I can go on with my  presentation.  Yeah, I think I can.  Okay, well, I'm so excited to be  here with you today. 

 As you know, I am from Mars.  And I'm really excited about the  idea of earthlings coming to  visit us some day, so I want to  tell you everything you need to  know to get to Mars safely.  And the first thing is that you  need to know where Mars is.  Mars isn't always in the same  place.  It's a moving target, right?  It's always orbiting around the  sun.  So, how are you supposed to  figure out where it is?  Well, one concept that helps you  is the idea of inertia.  And inertia says that objects in  motion tend to stay in motion,  and objects at rest tend to stay  at rest.  So here I have an object at  rest.  I have this tablecloth  underneath this beaker.  And do you think that I can get  that tablecloth out from under  the beaker without it moving?  >> Yeah. 

 >> You think I can?  All right, let's give it a try.  Let's see what happens.  One, two, three.  Am I doing something wrong?  >> Yes.  >> Okay, what am I doing wrong?  Going too slow.  So you think I should do it  faster?  So, what's actually going on  here, there's a force between  here.  So, objects at rest only stay at  rest if they're are no forces  acting on them.  And there's a force of friction  between this tablecloth and the  beaker.  But if I pull fast enough, I  should break that force of  friction.  And I think that I might be able  to--  (laughter)  get this out from underneath  the beaker. 

 Okay, so here we go.  I'm going to try it again.  One, two, three.  (musical flourish)  There we go.  (applause)  So, that is an object at rest.  And here, I'm going to show you  an object in motion.  So this is a ball.  And when I'm talking about  motion, I'm talking about  straight line motion.  So if I roll this ball across  the floor, you can see it starts  in a straight line and keeps on  going in a straight line,  because there are no forces  acting on it.  But this isn't what the planets  do, is it?  The planets move in circles,  right?  So there must be a force acting  on them. 

 And that force is called?  Gravity, right.  So, there is a force of gravity  because of the sun.  Here I have a model of the solar  system.  I've the sun over here.  I've got Mars over here.  And I've got this string  connecting them that represents  gravity.  I have this blade, and I'm going  to raise that blade and cut off  gravity.  I want you to predict what's  going to happen.  Remember, inertia says that  objects in motion like to stay  in straight line motion when  there's no force acting.  So, I've got gravity going on  here. 

 I've got Mars in orbit.  I want you to think about what's  going to happen when gravity  gets cut off.  You may start to rise out of  your seats, so be prepared for  that.  Here we go.  Cutting off gravity.  (musical flourish)  All right, so straight line  motion, like we said.  (applause)  I'm going to do a demonstration  of the conservation of energy.  And for this one, I'm going to  need a volunteer.  But I need a very brave  volunteer that believes in the  conservation of energy, okay?  How about you, right here.  Come with me. 

 What's your name?  >> Scarlet.  >> Thank you for volunteering.  I want you to come over here.  Peter is going to help me with  this one.  Could you come over to this  ladder and sit on the top rung  there.  This demonstration is completely  safe.  What's going to happen is, I'm  going to have Scarlet just let  go of this bowling ball.  It's going to swing out.  And when it swings back, the law  of conservation of energy says  that there is no way that it can  come up to a higher point than  it started.  So, this is going to get a  little scary, but it's going to  be completely safe. 

 So, are we all ready for this?  We're going to do a countdown  together.  We're going to say, three, two,  one, release.  Okay?  Ready over here?  Three, two, one,  release!  (slide whistle)  (laughter)  There you go.  So that is the conservation of  energy.  Thank you so much for your help.  (musical flourish)  (applause)  So, ask any astronomer.  They'll be able to tell you the  best time to go to Mars, thanks  to these physical laws.  That's all I have prepared to  say to you.  Thank you so much for having me.  And thank you, Professor Sprott,  for inviting me. 

 But, see, I have these balloons  that you gave me, and I should  really probably give them back  to you before I leave.  >> We don't need them back, but  I have an idea.  What do you think is in these  balloons?  >> Helium.  >> Helium? Are you sure?  >> Hydrogen.  >> How could we tell whether  it's hydrogen or helium?  What?  (audience giving suggestions)  Light a stick on fire?  (laughter)  You're sure?  Well, that's true.  Helium, as you know, doesn't  burn.  It's a so-called inert gas,  whereas hydrogen burns  explosively.  >> Wait.  Are you sure this is a good  idea?  >> Well, let's see.  (small pop)  >> Okay--  (laughter)  >> It didn't burn, did it?  Would you like to see it again?  >> Yeah!  >> Okay. 

 It wasn't so bad the first time.  >> No, of course not.  We'll do it with the second  balloon.  >> Okay.  >> Do you notice Mr. Weix with  his fingers in his ears?  If loud noise bother you, you  may want to do the same.  (loud explosion)  >> Oh!  (musical flourish)  (applause)  >> Well, you know Professor  Sprott, he seemed kind of tall  for a Martian.  I thought Martians were these    little green men.  >> No, that's a total myth.  Martians are not little green  men.  Martians grow to be very tall,  because there's very little  gravity there. 

 If you ever think you see a  little green man, you're  imagining things.  (laughter)  Anyway, our next visitor is from  the planet Mercury, which as you  know, is the smallest of the  planets, and it's the closest to  the sun.  You might think it gets very hot  there.  And of course, it does.  It gets to a temperature of 800  degrees Fahrenheit during the  day.  But the day is very long on  Mercury.  It lasts about 176 earth days.  So, there's a very long night.  And during the night, because  there's very little atmosphere  on Mercury, it gets very cold,  reaching a temperature of 300  degrees below zero Fahrenheit.  Mercury is about the same size  as our moon, and it has  mini-craters. 

 It has very little gravity.  Peter, would you bring out our  visitor from Mercury?  Mercurio Richuso.  >> Yes, Professor Sprott.  He's back here, sleeping.  (snoring)  I think he had a long trip.  (snoring continues)  He's kind of tired.  I bet you he's got a lot of  space lag.  >> Mercurio! Mercurio, wake up!  (snoring)  Wake up!  >> Oh, oh...  >> You're on! You're on!  You're on!  >> You woke me up!  I was hibernating.  It's really cold in here. 

 >> It's not cold in here.  It's 70 degrees.  >> Exactly.  I mean, I'm used to like 600  degrees.  Come on!  Can we at least turn up the  thermostat to like, I don't  know, 350?  >> I don't think 350 would work.  (laughter)  >> Mercury isn't just really  hot.  The dark side of Mercury, the  side facing away from the sun,  can get really cold, like  Professor Sprott said.  We don't really have seasons on  Mercury.  It's either really hot or  really, really cold.  >> So it's like Wisconsin?  (laughter)  >> That's why I feel at home. 

 All right.  Professor Sprott, since you woke  me from my slumber, I might as  well do some demonstrations  that'll kind of remind you of  Mercury.  I brought something with me that  reminds me of the cold side of  Mercury.  I brought something called  liquid nitrogen.  Liquid nitrogen.  Liquid nitrogen is a liquid that  is 321 degrees below zero  Fahrenheit.  That's its boiling point.  So, what I'm going to do, is do  a few experiments with it.  I'm going to scoop some up, and  I'm going to put it in this  cylinder.  I'm going to use my little cup  here. 

 Scoop some up.  Drop it in.  I'm going to hammer a cork on.  Pressure is going to build up  inside.  (scattered laughter)  And...  (cork pops out)  (musical flourish)  (audience reacting and talking)  >> So, pressure built up inside  and eventually the cork blew  off, because of the boiling  liquid nitrogen.  Let's do another one about  liquid nitrogen.  Let's see.  Ooh, what have we got here?  Oh, I need a volunteer.  This is a bag of marshmallows,  one of your favorite earthling  treats. 

 And I need a volunteer to verify  for the rest of the audience  that these are in fact regular  old marshmallows.  Have one of those big ones,  there.  Yes?  They are marshmallows!  And marshmallows are usually  soft and kind of squishy and  chewy.  Well, let's see what happens to  a marshmallow when you put it in  liquid nitrogen.  >> Oooh!  >> Because when things change  temperature, their properties  can change as well.  So, I'm just going to pour some  liquid nitrogen in my glass with  a few marshmallows here.  I'm going to let them get nice  and chilly.  We're going to do an experiment  to see how the properties of  these marshmallows have changed.  I'm going to pull this table  here.  Let me clear it off. 

 I'm going to take one out.  I'm going to use that hammer  that I used before to see how  these marshmallows changed.  I'll give it a little whack.  (musical flourish)  And it shatters.  (applause)  Let's do one more with liquid  nitrogen.  I have a balloon here.  >> Whoa!  >> Don't worry, it's a helium  balloon!  I promise.  And of course, helium balloons  float in air.  Let's see what happens when we  cool down the temperature of the  helium inside.  So, I'm just going to take this  balloon, and I'm going to pour  some liquid nitrogen on it. 

 Let's see.  Watch very closely to see what  happens to the balloon.  It shrivels up and shrinks.  And it loses its buoyancy.  But it will warm up slowly.  And go back up.  As it warms up, the helium  expands again to fill the  balloon.  And it becomes less dense than  air once more.  But it doesn't go up all the way  to the ceiling.  Why is that?  What's stopping it?  Yeah, the string. 

 The string is attached to it, so  it's not going all the way.  >> I have an idea.  Suppose we cut the string right  where it touches the table.  >> Okay, let's see.  >> Right about there.  And then we have a balloon  that's just capable of  supporting the weight of the  string.  It should go neither up nor  down.  That's something you can't do on  Mercury.  >> Thanks, Professor Sprott.  That's pretty neat. 

 >> Maybe I should cut off a tiny  bit more.  >> Let's see.  >> Try that.  >> Uh-huh, cool.  (musical flourish)  (applause)  I'll give it a little boost.  And we'll let it float around.  (laughter)  All right.  So let's do--  Professor Sprott mentioned that  I wouldn't be able to do this on  Mercury, because Mercury has no  atmosphere.  So, if I took that helium  balloon to Mercury, what would  it do?  It would float away?  >> It would fall down.  >> It would crash to the ground,  and it would sit there on the  ground, since Mercury has no  atmosphere. 

 Professor Sprott, what is the  atmospheric pressure here on  earth?  >> Here on the earth, we have  14.7 pounds per square inch.  >> 14.7 pounds per square inch?  That's ridiculous!  That's a lot of pressure!  Well, while I'm here on earth, I  need to take advantage of this  and do some experiments with it.  Mr. Weix, will you help me with  this one?  >> Sure.  >> I brought with me, two  hemispheres.  These are called magdeburg  hemispheres.  We're just going to put them  together.  We're going to remove the air  from inside.  >> I'll hook it to the vacuum  pump.  >> We're removing the air with a  vacuum pump.  This little scale here tells us  the pressure of the air inside  of the sphere. 

 And I need a volunteer for this.  I need an adult, like a dad in  the front few rows here.  You sir?  Would you help?  Come on down.  (scattered applause)  So we removed the air.  We closed the valve, so we won't  let the air back in.  How are you doing?  >> Pretty good.  >> Let's play a little tug of  war.  Let's see if we can get this  apart.  Ugh, come on.  We can pull harder than that. 

 Man, these things are really  stuck together.  Since we removed the air, there  is about 15 pounds per square  inch of pressure, all over this.  That's hundreds of pounds of  force.  So, we're not going to get this  thing apart.  I have an idea.  Let's start pulling, and let me  just release this valve and let  the air back in.  (musical flourish)  (applause)  Thank you.  There you go, Mr. Weix.  Thank you very much.  And for my final demonstration,  I want to experiment with  something called the Bernoulli  Effect. 

 It's what helps planes fly here  on earth.  We can't fly planes on Mercury.  You would just ram right into  the side of a mountain.  You would not get off the  ground, because there's no air.  Professor Sprott, would you help  me with this one?  >> Sure.  >> Professor Sprott, I went to  Lowe's and Home Depot, and I  bought one of these leaf blower  things that you use.  Do you know how to use one of  these?  >> Yeah, I have one of these at  home.  >> What do you use these things  for?  >> Well, you blow leaves into  your neighbor's yard.  (laughter)  >> Oh.  Well, it can make a pretty good  scientific piece of equipment,  as well, because it moves air in  a stream. 

 Let's do a little experiment.  (turns blower on)  (musical flourish)  (applause)  Thank you, Professor Sprott.  So, it wasn't actually the air  pushing under the ball that held  it up.  It was the flow of air around  the ball.  The Bernoulli Effect says that  moving air has lower pressure.  And that's what kept the ball in  the stream.  Pretty interesting.  Well, Professor Sprott, that's  everything I brought today.  Wait a second.  This wasn't here when I came  out. 

 Pluto is a planet.  This is ridiculous!  This is absolutely preposterous!  Mercury is the smallest planet.  That's our claim to fame, and  we'll always be the smallest  planet.  Pluto is not a planet!  Thank you.  (musical flourish)  (applause)  >> Well, the previous visitors  were from the inner planets,  the ones close to the sun.  Our next visitor is from one of  the outer planets, Saturn, which  is the sixth planet from the  sun, and the second largest in  the solar system.  Almost a thousand earths would  fit inside of one Saturn.  Now, many people recognize  Saturn by its beautiful rings.  But it's now known to have 60  moon, one of which, Titan, is  half as large as the earth, and  has a dense atmosphere.  Saturn, unlike the inner  planets, is made up mostly of  hydrogen and helium gas,  surrounding a small, dense,  metallic core. 

 Despite its large size, the  gravity on Saturn is about the  same as it is here on the earth.  But because Saturn is ten times  farther from the sun than is the  earth, it's very cold there.  Peter, if you would bring out  our visitor from Saturn,  Professor Koosh Koosh.  >> Yes, Professor Sprott, he's  right here on this cart.  We made a special cart for him.  I'll just park it right here.  The only instruction I have is  to plug in this cord here, just  like that.  Hi, Professor Koosh Koosh.  Did you enjoy the trip?  (electronic, musical tones)  >> I can't understand a thing  he's saying.  (electronic, musical tones)  >> I can't understand him,  either. 

 >> There must be something wrong  with his language translator.  Is there anyone in the audience  that speaks Saturnian?  (electronic, musical tones)  >> I speak Saturnian.  >> George, welcome.  >> Hello.  >> Can you translate?  >> I'd be happy to.  Professor Sprott,  Professor Koosh Koosh wants to  thank you for being here, and he  wants to thank all of you for  being here, as well.  We're here to talk about sound  today.  You might ask what sound has to  do with astronomy.  Well, it turns out that most of  the information that we get from  astronomical bodies comes to us  in the form of waves.  And one of the easiest waves to  understand is sound. 

 If you understand one kind of  wave at some level, you  understand most.  Professor Koosh Koosh here  speaks in a voice that's so high  frequency, in other words, it  vibrates so fast, we can't hear  it.  We call that ultrasonic.  I have here a demonstration of  ultrasonic sound.  This device acts both as a  speaker and as a microphone.  It's called a transducer.  And it vibrates in ultrasonic  frequencies.  And what will happen, is I'll  get this going.  It will actually catch the  vibrations in the water, and it  will break the surface of the  water into droplets, and throw  them up into the air.  And there you see it. 

 This is called an ultrasonic  mister.  (musical flourish)  (applause)  Now, with this demonstration, we  find an effect that was first  discovered by Ernst Chladni,  from the 1600s, in fact, in  1670.  He's often called the father of  modern acoustics, the science of  sound.  He took a metal plate, such as  this, and he drew a bow of a  violin along one side of it, and  got the plate to vibrate in a  special way that we call  resonance.  And he poured common, every day  table sand on it.  And what'll happen, is the sand  will collect in the places that  the plate are vibrating the  least.  You'll get interesting geometric  patterns.  Let's see what happens.  You'll see how fast the plate is  vibrating on the frequency  counter there.  It's currently vibrating at 482  times per second. 

 (monotone note)  And you see the geometric  pattern.  We can go a little lower.  We can go down to 330 times per  second.  (lower note)  You can see the pattern changes.  We can go higher than that, as  well.  Now we're up about 710 times per  second.  (higher note)  This is called a Chladni plate.  (musical flourish)  (applause)  This is interesting, because  stars vibrate just like this  metal plate does.  The surface of the stars,  including the sun, vibrates.  We can study the waves coming  from the star in the form of  light. 

 And using mathematical  techniques that we would use to  analyze this, we can infer the  kinds of vibrations that we're  seeing on the surface of that  star.  Now, materials vibrate, and here  we have a special kind of fluid.  This is a solution of corn  starch.  What I will do is I will put--  I will vibrate this speaker,  which will vibrate the material.  You'll see a pattern of waves  form in there.  This was first done in 1870 by  the amateur scientist Michael  Faraday.  He may have been the greatest  amateur scientist who's ever  lived.  There you can see the pattern of  waves.  Now, we can increase the  frequency, and you'll notice  that the pattern changes.  We can decrease it, and the  pattern changes again. 

 You'll notice that as long as we  keep the frequency steady,  despite the fact that this is a  fluid, the waves pretty much  stay in one place.  When that happens, we call that  a standing wave.  And this is a special kind of  standing wave.  This kind of fluid, when you  vibrate it, the fluid almost  becomes like a solid.  So we call this a Faraday wave,  after Michael Faraday.  (musical flourish)  (applause)  Professor Koosh Koosh wishes to  thank you, Professor Sprott, for  being here, and wishes to thank  all of you for being such a  gracious audience.  (musical flourish)  (applause)  >> Okay, oh, excuse me.  Who are you?  >> My name's Adam Beardsley.  >> Adam Beardsley?  That's a familiar name.  Didn't I read a newspaper  article about you recently?  >> That's right. 

 You probably read about my  discovery.  You see, I was in an astronomy  class here at the UW last  semester, and my class  discovered a brand new galaxy.  >> Wow, that's impressive.  Can you tell us something about  it.  >> Sure.  The cool thing about our galaxy  is that it's located in what's  called the zone of avoidance.  To understand what that means, I  brought along a couple of  pictures to show you.  You see, this is the Milky Way,  as you can see it from the  earth.  As you can see in the center,  there's a lot of light, a lot of  stuff, right?  If you try to look past the  Milky Way, you can see a lot of  things around it, but you can't  see a lot through it, because  all that stuff in the center  gets in the way.  So if you want to look through  it, you have to look very hard,  with a very powerful telescope. 

 That's exactly what we did.  We used this.  This is the Aricebo Telescope.  It's located in Puerto Rico.  This thing is so big that you  could fit three football fields  inside of it.  This is exactly what we use to  discover a brand new galaxy.  >> Will you tell us something  about this galaxy?  How far away is it?  >> Sure, it's about 250 million  light years away.  That means if we tried to  communicate with aliens in this  galaxy, it would take over 250  million years for them to get  our message.  We also know that it's roughly  about the same size as our own  galaxy.  Hmm, it probably makes you  think. 

 Maybe there's an alien physics  professor out there somewhere,  giving a demonstration show  right now.  >> I don't know if I believe  that, but I guess it's possible.  (laughter)  Well, I must be going.  I'm heading to Puerto Rico right  now to check out the new galaxy.  Have a great show.  >> Thank you.  (musical flourish)  (applause)  >> Well, it is true that a group  of students in one of our  astronomy classes right here at  the university discovered a new  galaxy.  Maybe some of you some day will  come to the university and take  an astronomy course, and maybe  you will have the chance to  discover a galaxy, because  students can do that.  Our next visitor is from the  planet Venus, which is the  second planet from the sun, and  the closest planet to the earth.  Venus is sometimes called our  sister planet, because it's  almost the same size as the  earth, and its composition is  very similar. 

 But Venus is a very inhospitable  place.  It has an atmosphere that's a  hundred times denser than the  atmosphere here on the earth.  And it's made up almost entirely  of carbon dioxide.  Venus is shrouded by thick  clouds of sulfuric acid.  It has 200-mile-per-hour winds,  and violent electrical storms.  And the surface temperature is  even hotter than Mercury,  reaching 900 degrees Fahrenheit.  Because Venus is shrouded by  thick clouds, we can't see the  surface.  But radar images show tall  volcanoes and deep valleys.  Some people think Venus shows  what the earth might be like  some day, if global warming  continues.  Now, because Venus is rather  inhospitable to life, our next  visitor is a little bit  peculiar. 

 His name is...  skinny bar, skinny bar, fat bar,  fat bar, skinny bar,  skinny bar--  Well, we call him Professor  Barcode.  Peter, would you bring him out?  >> Yes, Professor Sprott.  I was just back at the space  dock, and this special delivery,  a big metal crate here, was  delivered.  They put it on some casters for  me.  They also gave me this really  nice 500-page manual.  >> Now, wait a minute, we don't  have time for a 500-page manual.  People are anxious to see this.  >> Well, you know, I do take  some shortcuts around here.  >> I noticed that. 

 >> Let's try this.  I see this big switch on the  side, and I really like  switches.  Let me just throw it and see  what happens.  There we go.  >> Greetings Earthenoids.  Beginning speech procedure.  Hi, I'm Professor Barcode.  I'm here today to talk to you  about the force of electricity.  Now, do you remember earlier,  when Kukas Klukas was talking  about the force of gravity?  Well, the force of electricity  is a lot like the force of  gravity, only a billion,  billion, billion billion times  stronger.  And also, unlike gravity, which  only pulls things together,  gravity can also push things  apart. 

 The way it does this, is by  having two types.  We call them charges.  You can have positive charges  and negative charges.  If they're the same type, a  positive and a positive, they  push apart.  If you have a positive and a  negative, they pull together.  Let me have a demonstration.  What I have here is a little  ball.  And I'm going to negatively  charge this ball.  Drop it, positively charge my  hand and pull it back up before  it hits the ground.  Okay, you ready?  (loud cricket chirping sounds)  You didn't assemble me, did you,  Peter?  >> No, I took a shortcut this  time. 

 (laughter)  >> Well, I have a backup plan.  I brought with me, from Venus,  this wand.  And I can charge up the end of  this wand with negative charges.  I brought with me this metal  moth.  I'm going to drop him onto this  wand and charge him up with  negative charges, too, so him  and the wand should repel, and I  can cause him to fly.  So let's see.  There we go.  And I can use it to defeat the  force of gravity.  This is something we call static  electricity.  You might be familiar with this  in a few forms. 

 Catch that.  A few forms that you can do  here on earth.  You take a balloon and rub it  against your... fur?  Hair, yeah, rub it against  your hair.  You can stick it to a wall.  Also, if it's a cold day, and  kind of dry out, you can,  wearing socks, rub your feet up  against the carpet and go up  and touch your cat.  (laughter)  If you do this,  please videotape it.  I have another demonstration.  I have an electron gun here.  (buzzing)  And I have a tube here  that I can cause to light up.  Yeah, it does say UW. 

 >> I bet that stands for  University of Wisconsin.  >> No, actually, it stands for  University of West Venus.  Charging capacitors.  Sine, sine, cosine, sine,  3.14159.  (laughter)  So, when I lit up this sign  here, it's a red color.  It's not the green color  we saw before.  I have two tubes here.  This one is filled with a gas  called neon.  It glows kind of a red-orange.  This one is filled with a gas  called mercury. 

 It glows what color?  Blue-purple-indigo.  We're going to go with indigo.  You might ask yourself, okay,  how is this useful for me.  Let's pretend you're an  astronomer, and you're  interested in a star that's  thousands of light years away,  like stars are.  You can't exactly get into a  rocket ship and travel out there,  grab some, come back to your  lab, and put it in your mass  spectrometer to see what's in  there.  Well, I could, but I wouldn't  want to, because that would take  too long.  And I don't think you guys will  live thousands of years.  You can't break that universal  speed limit, C.  So, how are you going to figure  out what's in that star?  Well, it turns out stars are  very hot.  They have a lot of free  electrons moving about. 

 And they can interact with  various gases.  If you look at that star and see  this color, see this neon type  color, you can say, oh, there's  neon in there.  Or if you see this indigo, you  can say, oh, there's mercury in  that star.  So you can figure out what's in  distant stars without actually  having to travel there.  It's something very useful that  earth astronomers do all the  time.  Maybe this is a bit far afield.  I want to get back to  electricity.  So, one more thing I want to  talk about is one of the most  wonderful demonstrations of  electricity that we have in  nature.  It happens on my planet.  It happens on your planet. 

 What happens when you have a  violent storm?  You have clouds rubbing against  each other, and you cause charge  separation.  >> Lightning.  >> Lightning, right.  (thunder crashing)  And thunder.  I wanted to show you  some of this.  Professor Sprott, could you  bring in that lightning storm we  talked about?  >> Well, we did talk about  making a lightning storm in the  room here, but everyone would  get wet.  >> Ah, yes, rust.  >> I don't know about that, but  we do have something that would  demonstrate what lightning looks  like.  Would you like to see?  >> Yes, most definitely.  >> It's our million-volt Tesla  coil. 

 >> A million volts?  That'll do nicely.  >> It makes lightning bolts.  >> That up there kind of looks  like a cloud.  Let's get that moving.  (electrical buzzing)  (musical flourish)  >> Professor Barcode!    Professor Barcode!  Professor Sprott, something's  happened with Professor Barcode.  (laughter)  >> Uh-oh, we must have zapped  his electronics with the  high voltage.  >> Oh, yes.  I need to stick him back in the  box here.  I'll just put a big "return to  sender" sticker on the crate  and put it back on the dock.  >> Okay. 

 (musical flourish)  (applause)  >> Our next visitor is from the  planet Jupiter, which is the  fifth planet from the sun, and  the largest of all the planets.  Jupiter is slightly closer to  the sun than Saturn is.  And most people don't know that  it has a faint ring system and a  very strong magnetic field, much  stronger than here on the earth.  Like Saturn, Jupiter is composed  mostly of hydrogen and helium  gas.  But it also is known to have at  least 63 moons, one of which,  Ganymede, is larger than the  planet Mercury.  Jupiter also has a giant red  spot that's been there for  hundreds of years.  It's bigger than the earth, and  it's thought to be a hurricane.  Jupiter's gravity is about two  and a half times greater than  the gravity here on the earth.  And it's mass is two and a half  times greater than the sum of  all of the other planets  combined.  Now, because of Jupiter's very  large magnetic field, we've  flown in from the cloud city  of (slide whistle), a specialist  in magnito navigation. 

 Professor Crackaaaaaaw.  (bird chirping sounds)  Sorry.  Sorry about that.  I'm having a little trouble  feeling where I'm going.  Your magnetic field is so small  here.  Well, I think I'm getting used  to it.  This will work out.  Oh, yes, magnetism.  I was brought to talk about  magnetism.  As you all know, it is very  difficult to travel in a  straight line, especially over  long distances, like when you  migrate south in the winter,  without using your magnetic  sensing organ to follow the  field line. 

 Isn't that right, Professor  Sprott?  >> Well, no.  Actually, we humans don't  migrate.  >> Bah-caw?!  >> No, and we don't have  magnetic sensor organs.  >> You don't?  >> No.  >> How do you survive?  I have so much to learn.  Well, maybe we can learn from  each other here today.  Because I brought several  demonstrations to teach you  about magnetism.  I'd like to start with something  I know that no one in this room  has ever seen before.  We just discovered this on  Jupiter a year ago.  That'd be about 12 of your earth  years. 

 I like to call it a permanent  magnet.  If I take it near certain metal  objects, like these nails, I can  lift them!  (musical flourish)  You've never seen anything like  that before, right, Professor?  >> We've had permanent magnets  on the earth for hundreds of  years.  >> Bah-caw!  Ruffle my feathers!  You're kidding?  >> No.  >> Well, if you're used to  these, maybe I'll show you  something else.  Over here, I brought a  demonstration of something I  like to call a temporary magnet.  In this device, we have a coil  of wire.  We're going to pass some  electric current through that  wire.  And what that will do is create  a magnetic field, a strong  magnetic field that forms very  quickly.  It gets pushed through the  center of this aluminum ring.  So as you may know, aluminum is  not a magnetic material. 

 It doesn't stick to a magnet at  all.  But when I push a magnetic field  through here very quickly, it  will become a temporary magnet.  That temporary magnet will be  aligned in the opposite  direction of the magnetic field  we started with.  So it's a bit like putting two  north ends of magnets together.  Do you know what happens when  two north ends get pushed  together?  Shout it out.  What happens?  They repel, I heard someone say.  Let's see.  If that's right, then when I  push this button, the ring  should create a temporary magnet  and repel up into the air.  Shall we try?  Okay, three, two, one.  (musical flourish)  Did you see it?  I'll do it again. 

 Ready, here we go.  (metallic clanging)  Now, that's pretty neat, but  it's not very impressive, is it?  I think we can do a little  better.  I have a big piece of iron.  I'm going to take this and put  it through the middle.  We should increase the magnetic  field that we're pushing through  that ring, which will make the  reaction, the repelling action,  much stronger, and the ring  should go higher.  Think we should try it?  >> Yeah.  >> Okay, here we go.  Three, two, one.  (musical flourish)  (applause)  You know, you earthlings have  come up with a crazy idea.  I saw some liquid nitrogen out  here earlier in this show. 

 And you earthlings have come up  with a theory that if you get a  metal, like this aluminum, cold  enough, like to the temperature  of liquid nitrogen, it will  become a much better conductor.  Now, what I didn't tell you  about this device before was  that the reason this ring  produces a magnetic field, was  because when I push the magnetic  field through in the beginning,  it creates a current that flows  through the ring.  And that current creates the  temporary magnet.  So when I get this ring much  colder, it should increase the  ring's conductivity, which will  make a larger current, which  will make a larger magnetic  field in the opposite direction.  And so maybe we can get it to go  even higher.  Shall we try?  >> Yeah!  >> Okay, I need to wait just a  minute more, until the ring  stops boiling.  When the liquid nitrogen stops  boiling, we know that the ring  is at the temperature of liquid  nitrogen and is cold enough.  That looks like  it's just about ready.  Nice and cold.  Here we go. 

 Three, two, one.  (musical flourish)  (applause)  You want to see it again?  >> Yeah.  >> With the...?  (music)  (laughter)  Okay.  I've never done this before,  though.  Those of you in the front row  might want to duck your heads.  We'll see what happens here.  Nice cold ring.  It's a little difficult  to pick up.  I don't want to stick my hands  in there, because I might freeze  my fingers off.  There we go. 

 See what happens.  Okay, look out below!  Three, two, one.  (musical flourish)  (applause)  And this last device here, I  want to show you we created a  very special pair of magnets.  These have coils wrapped around  them, and current flowing in  opposite directions.  They've been specially made to  work with this special piece of  aluminum, to create just the  situation to achieve something  called magnetic levitation.  (musical flourish)  (applause)  That's not the only object we  can levitate.  We can also do it to this  aluminum cylinder.  I remind you that aluminum is  not a magnetic material, and  yet, we can levitate it using  nothing but the magnetic forces  created by these magnets, and  the currents induced inside the  cylinder.  You know, I've heard you  earthlings have gotten very  creative with this concept.  You've used magnetic levitation  to levitate other objects, such  as a living frog. 

 >> Whoa!  >> And also, really big things,  like a passenger train, if you  believe it.  So, you can see that magnetic  levitation may have some really  neat technological advantages in  the future.  Something to watch out for.  I want to show you one last  demonstration here that involves  a little bit different  situation.  In all the previous ones, we had  a stationary magnetic field that  we used to create a temporary  magnet, using a piece of  aluminum, which moves the  aluminum in some direction.  In this last demonstration, we  have the same thing but with a  twist.  We've got a very strong  permanent magnet and a  stationary conductor.  In this case, it's copper, but  it's a lot like aluminum.  It's a little bit better  conductor.  And in this case, we'll have a  moving magnet and a stationary  conductor. 

 You can see that the same  principles apply.  When the magnet gets close,  it'll induce what are called  eddy currents to flow in this  copper piece.  We'll see what happens if I push  it over.  Watch closely.  Did you see what happened?  It falls a little bit slower  near the end.  And in fact, I can even drop it  from a few inches above.  >> Whoa!  >> And it slows down at the last  inch or so of the fall.  Well, you know, I want to play  one more time with this idea of  your earthling scientists, that  if you cool a piece of metal  down, it will be a better  conductor.  So here I have exactly the same  copper plate, but cooled down to  the temperature of liquid  nitrogen.  And I think, if my calculations  are correct, the effect should  be even stronger in this  situation. 

 Let's watch.  >> Whoa!  >> I can even hold it up and  drop it, and maybe, for a brief  moment, achieve another form of  magnetic levitation.  (musical flourish)  >> Cool!  (applause)  >> Isn't this thing neat?  It's so shiny.  (laughter)  So strong.  So bright.  It's really cool.  Whoa-oh!  Um-- What?  I got a little close there.  (birds chirping)  This probably ought to be--  I've got to go sit down.  (birds chirping)  (musical flourish)  (applause)  >> Well, you know, Professor  Sprott, do you think he went  back to Jupiter to hatch some  new ideas?  (audience groans and laughs)  >> I don't know about that, but  he didn't lay an egg when he was  here!  Well, our last visitor is from  Pluto, which as you know, used  to be considered a planet, until  the year 2006, when astronomers  decided to reclassify it as a  dwarf planet because of its  small size and rather unusual  orbit.  We now know that there are other  dwarf planets in the solar  system. 

 Because Pluto is very far from  the sun, as you might expect,  it's very cold there.  It has very little gravity and  very thin atmosphere.  Pluto is slightly smaller than  our moon, and it has a surface  with many craters.  In fact, there are five moons in  the solar system that are bigger  than Pluto.  Well, our guest from Pluto is  named Plutara.  And I think she's been here  before.  We brought you here to talk  about physics, not to protest  the status of Pluto!  >> I only get to talk about  physics for about ten minutes.  I can protest about Pluto all  day long.  Since after all, you know, you  demote us to dwarf planet, and  then you invite us to an  interplanetary conference on  physics.  It doesn't seem to make a lot of  sense. 

 I'm a little concerned that you  maybe think you're better than  we are, as humans, versus  Plutonians.  So I just wanted to correct the  record of Professor Barcode  earlier, who seems to have made  a mistake in what he was telling  you.  If you would be so kind as to  turn on the lamp over there, the  one he called "indigo," perhaps.  That is actually not indigo.  And we on Pluto see colors as  they actually are, not as you  see them, which is all the  colors together.  So I can see this, which is that  lamp is actually a little bit of  purple, a little bit of blue, a  little green, orange maybe.  And that's why I wear these  glasses, so I can see the way  you do.  But so you can see the way we do  up there, we have a camera here  with a light splitter on it,  pointing at that lamp.  So, he wasn't really telling the  whole truth.  That's not really indigo. 

 It's really a number of  different colors all together.  The same type of thing happens  with a rainbow.  A rainbow works, well,  obviously, for a rainbow, you  need the sun and the rain  together.  Rain doesn't make a rainbow.  And the sun doesn't make a  rainbow, either.  We have a sun and something  that's kind of like a raindrop  here.  The raindrops work as the light  splitter and they separate the  sunlight into all of its  constituent parts.  That's what we see.  We see the pure colors on Pluto,  because we are much better than  you guys here.  We have a lot of other things  that we're better than you guys  at, so I brought some photos to  show you. 

 If you look up here, we have,  for example, well, focus your  eyes in the middle of the right  one or the middle of the left  one.  And you can see that they turn  on their own.  These are very useful, because  if you put them in your watch,  you know, you never have to wind  your watch ever again, right?  That's pretty handy.  And we also have three pronged  magnets.  We use these in the lab all the  time.  You guys only have two ends,  because you only have two poles.  Well, we have three.  We also have some ink that you  can only see if you're not  looking at it.  We use it for military purposes.  I think your military might find  this very useful. 

 And we also have a perpetual  motion machine that we started  about 200 years ago.  >> Wait a minute, wait a minute!  Professor Sprott, are you  believing any of this?  >> No, there's no such thing as  a perpetual motion machine.  You think we earthlings are  stupid?  >> If you don't believe me, then  I'll show you something in real  life.  I noticed on my way in that  there's this fancy demonstration  here.  This will allow me to show you  what we do on Pluto to make fire  under extreme conditions.  It's really cold there, right?  So we've learned to make fire  and heat when it's cold, and  sometimes when it's wet, too.  I'm going to show you how we    make fire under water.  You'll have to excuse my sun  shade.  It's really cold out there, and  we don't get a lot of light, so  if I remove it, I might melt.  That would be a little bit  tragic, I think, and may be  disturbing for some of the  audience members. 

 If you look up on the screen, it  should be pretty clear.  As soon as I move, you'll be  able to see the candle under the  water.  Isn't that cool?  Don't you wish you could do that  here?  >> Wait a minute, wait a minute.  There's no candle burning under  the water.  The candle is out there.  And the water is back here.  >> No!  >> Look.  >> You weren't supposed to be  able to see that!  That's not fair!  I suppose now I have to tell you  how it works.  There's a candle here.  There's the water there. 

 And there's this glass plate in  the middle.  You can see through the glass  plate, which allows you to see  the water, just like that.  And it also reflects light,  especially when we turn the  lights down, so then you could  see the candle reflected really  well.  That's something that we call  an illusion.  And maybe you know  what an illusion is.  It's something that seems one  way, but it's actually another  way.  And maybe you guessed, but those  photos I showed you earlier,  those were illusions, too.  This is a bit of a sticky  situation, because we really  didn't think you earthlings were  that smart, so we didn't think  you'd catch on.  Well, I guess I might as well  tell you.  My last demonstration is also an  illusion. 

 Maybe instead of trying to pass  it off as real, we'll let you  guess and see just how smart you  actually are.  But I'm going to need a  volunteer.  Huh, you're hand was the  fastest.  I guess you'll have to come up.  Are you ready to have your head  cut off?  >> Sure.  >> Sure?  Okay, well, excellent.  If Professor Sprott and Mr. Weix  would be so kind as to hold up  this red cloth here, I would be  happy to put your head on this  plate.  All we need to do is get you to  stand here.  Put your head there.  Let me just get out my knife  to perform the surgery. 

 And a couple incisions.  One here, one there.  Uh-oh, don't move now.  I might cut your head off.  No, no, you better--  Yeah, yep, just like that.  Otherwise, I might cut  the wrong thing.  Okay, so now let's see.  (laughter)  Okay, there we go.  I think he might even still be  alive.  Wouldn't that be handy?  Okay, so let's see it  (musical flourish)  (laughter and applause)  Now, what was your name?  >> Michael. 

 >> Michael, how old are you?  >> 13.  >> You're 13, and you don't mind  having your head cut off?  >> No, I don't.  (laughter)  >> That's good.  Maybe we should quit  while we're ahead!  Maybe you've guessed  the illusion.  Can you see it?  There's a mirror under here,  isn't there?  Where is the mirror?  Is it here?  No, it's diagonal, isn't it?  If you don't make it diagonal,  it doesn't create the right  effect.  So, let's get you out of here.  See?  (musical flourish)  (applause)  Thank you for volunteering.  Well, that's a bit surprising.  We really didn't think you  earthlings were smart enough to  figure it out.  So, hmmm, well, I suppose the  only option left is for you guys  to upgrade yourselves to dwarf  planet status, so that everybody  else will know that you're just  as smart as we are. 

 Doesn't that sound like a good  idea?  I think  that's the right answer.  Okay, well thanks so much  for having me.  Have a good day.  (musical flourish)  (applause)  >> You know, there is a lot of  physics in magic.  To be a good magician, you have  to know some physics.  Do you know the difference  between a magician and a  physicist?  They both do interesting  demonstrations, but the magician  never tells you how it works.   The physicist, you can't get him  to shut up about it!  (laughter)  But anyway, so far as we know,  the only place in the solar  system where life really exists  is right here on the earth, the  third planet from the sun.  But you know, the universe is a  very large place.  There's something like a hundred  billion galaxies, each with ten  to a hundred billion stars.  And we now know that many of  these stars have planets. 

 And some of these planets almost  certainly have conditions  conducive to life, maybe even  intelligent life.  So it's possible that life  exists in many places throughout  the universe.  (laughter)  But most of those places are  very far away.  And it's very unlikely that  we'll ever come in contact with  an alien from another distant  galaxy.  But you know the earth is a very  special place.  It's teeming with life of an  enormous variety.  That's because the earth is  neither too hot nor too cold.  But like Goldilocks, it's just  right for the existence of  liquid water, which of course is  what we need to support life.  However, humans are doing things  that threaten the climate and  other conditions here on the  earth.  And it's possible that some day,  maybe the earth will not be able  to support life. 

 So we humans have to be very  careful to preserve the  conditions that allow us to be  sitting here today, learning  about the wonders of physics.  Now I'd like to conclude the way  we have concluded every one of  the shows for the past 26 years,  by making for you a cloud, the  kind of cloud that exists in the  solar system, only right here on  earth, a cloud of condensed  water vapor.  And in order to do that, I bring  out a container that has 25  liters of liquid nitrogen.  We force nitrogen gas into it.  That forces the liquid to come  out these holes on the top.  That cools the air.  The water vapor in the air then  condenses into tiny droplets of  liquid water.  That's what we call a cloud.  So with that, I will put on my  hat and thank you all for  coming.  (applause)