字幕列表 影片播放 列印英文字幕 Uhm. Excuse me. Pardon me. No, no no. Not up there. I'm down here. Yup. Hello! I am a scientist. And I've come to improve your situation just a bit. See that fire over there? Have you ever really wondered what the flames are from that fire? I mean look at all of those colors. And you feel that heat. It's hot, right? Well gee, it must be torture being around all these flames and not knowing what they are. Here, take a look at this cupcake. You see a flame on top of this delicious looking cupcake? You do like cupcakes, don't you? Let's take a closer look, shall we? Fantastic! If we look at the flame on top of this cupcake, we first notice a few things, like all the colors At the bottom, we have this blue-ish color. On the top, it's more yellow, orange, redish. Also the flame is hot. Why is it so flaming hot? Well, to answer these questions, you need to know something very important. You see everything is made up of tiny things called atoms. And these things are the building blocks that make up everything! And they're really small. Smaller. Smaller! Even smaller! Hey, look, you can't even see them, they're so small. Exactly! Anything you can think of is made up of atoms. Yup, this air condition is made up of atoms. This delicious popsicle is made up of atoms. This ice water is made up of atoms. Everything is made up of billions and billions of atoms. Now, this candle and flame are made up of three kinds of atoms carbon, hydrogen, and oxygen. The carbon and the hydrogen are locked together to form the solid wax and wick. The oxygen is a gas all around us. Normally, the oxygen doesn't do much to the candle It just bounces off of the surface, not doing any real damage. But when we add heat, the oxygen atoms go bananas! And they shake the wax, like crazy! Until finally, with enough force, they snap apart. They leave the candle as a gas. where they mix with the oxygen. Uh oh, I smell trouble. Well the fancy science word for all of this is pyrolysis. It is the first thing that needs to happen to get a flame. It's when the fuel turns to a gas. Now let's see what happens when these hot gasses combine. Announcer: Ladies and gentlemen, in this corner he was once a solid, now he's a gas. He's the fuel from the West! And in this corner, not one, but two groups of oxygen Ready? React! Narrator: Any time certain atoms get hit hard enough, they spit out blue light. And because there are lots of atoms getting hit hard and lots of atoms spitting out blue light we get a blue flame. Here comes another science word. Ready? Chemiluminescence. I know, it's a big one. One more time. Chemiluminescence. It's when atoms shine light when they rearrange. It's why flames are blue Now the blue light is not hot. Wait! But the blue flame is really hot! So if the blue light is not the hot part, then what does make a flame so hot? Well, remember our fuel atom? and our oxygen atoms? They rearranged to make new stuff like water and carbon dioxide. And as they rearrange, they snap together. And with each snap the new thing shakes like crazy! So when the rearranging is done, we have lots of new stuff all shaking really fast! If we put something close to those raging atoms then those atoms begin shaking like crazy too, like the atoms in our fingers -- that's heat. This is called oxidation. It's when the oxygen atoms combine with other atoms to make new stuff. It's why flames are so hot. Alright then, why are most flames yellow, orange, red? Well, remember our first reaction? We had one group of fuel atoms and two groups of oxygen. They made a flame that was very hot. And only blue. But watch what happens if there's not enough oxygen and we take some away. Announcer: Ladies and gentlemen what happens when there's not enough oxygen? audience gasp Announcer: what's this? A single carbon atom left all alone! Narrator: It's okay, because all of his left-over carbon friends come to join him and they form large, black particles we call soot. Okay, they're not so large. They're so small we can't even see them. But to a single atom, they are enormouse! Announcer: Enormous! Narrator: I know what you're thinking. How do black particles make yellow flames? Well let me show you. But first, I need something big and black like this pitch fork. Excuse me sir, Your Evilness, could you please place your pitch fork in those scorching flames? Thank you. Big black objects are like sponges that soak up heat. They have to get rid of this energy, so they spit it out by glowing. The hotter they get, the more brightly they glow. Now the same thing happens with our soot particles. They drink in heat from all those hot atoms. And they glow brighter and brighter! Until they look like this! And because there are millions and millions of soot particles all glowing hot we get this yellow flame. Audience: ooh! This is called incandescence. It's when the soot particles glow because they're hot. it's the reason why flames are yellow. Well, that's it. That's what flames are. I mean, who knew cupcakes could be so much fun. Remember, first the fuel loses mass and turns into a gas. Before the next change is through, atoms shine blue. When the process is complete, it gives off heat. Extra carbon will grow red, orange, and yellow. Hey, those are just like the lyrics from that really awesome song about flames. You know, the one that goes: The fuel loses mass it turns to gas. Before the next change is through some atoms shine blue. When the process is complete it gives off heat. Extra carbon will glow red, orange, yellow. The fuel loses mass it turns to a gas Before the next change is through some atoms turn blue. When the process is complete it gives off heat. Extra carbon will glow red, orange, yellow. chorus repeats vocal backing: Pyrolysis Chemiluminescence Oxidation Incandescence repeat song finishes