 Hello, hello again, friends. Thanks for joining us. We've had such a busy day, and it is not over yet. We have a couple of more really interesting experiments and demos here for Super Science Saturday today. So I'm going to introduce you to some really special friends in just a minute, Zeus, Poseidon, and Athena. You may have heard their names before. And they came across a very mysterious thing recently that they're going to dive into a little bit with you. A very interesting science question having to do with some gases in the air, which here at NCAR, the National Center for Atmospheric Research, is what we spend a lot of time studying, different gases in the air and how the air moves and how the air works. And so I think they'll probably tell you a little bit more from there. I'm going to turn it over to Zeus, Athena, and Poseidon. Well, good to see you all here. This instance you're about to see came across because I saw something funny happening around me and I investigated. And that's the essence of science is looking, making observations around you. There's another portion of it. I came across a problem and I thought I could beat my head against the wall and solve it myself after a long time. But I thought, I'm going to talk with a friend who's very positive. Worked out the problem together. Welcome to Super Science Saturday. I am Zeus, God of Thunder and Lord of the Sky. But today I'm just dad because, you see, tomorrow it's Athena's birthday party. She's going to be 3,500 years old. And Neptune and I are preparing a surprise party for her. We got some nice birthday balloons here and some ambrosia and nectar. And we're going to get it all ready and we're going to have a good party. All right, let's go. What's going on here? What's going on? Oh, that was weird. The ambrosia fell over, but these balloons, when I started up, they went forward. That's peculiar. Let me try that again. Balloons go forward as I accelerate. And then when I stop, they go forward. One more time, one more time, just to be sure. Accelerate. This is very peculiar. I could figure this out, but I'm going to talk to my brother, Neptune. He's the god of the sea and he knows all about fluids. And something about this reminds me of fluids sloshing back and forth in the tides and the ocean. So I'm going to go talk to him and we'll figure out this little problem here. Well, here I am on Mount Olympus. Got to call Neptune, but since we're in Greece. Hey, Poseidon! It's probably off on a dive trip with Percy Jackson. Poseidon! Hey, Zeus! Hey, Poseidon, what's going on? Yeah, I just got back from my afternoon dive. Excellent. You got your trident? Well, I had to check the trident at the door. I'm actually heading over to the barbeque. All right, yeah, it's going to be fun. Athene's going to be 3,500 years old. Wow, can you believe that? I got a quick question for you though. Yeah. You know how balloons normally when I go somewhere, they drift behind me, see, like this. And then like that. Sure, yeah. I was in the car and when I accelerated, they went forward. And this was really strange. So since you're a fluids god and also hydrodynamics and stuff, maybe you could explain just what's going on here with these balloons. Yes, well, you came to the right person, Zeus. Yep. So the thing is that air is fluid. So it has mass, and it has momentum, and it responds to changes in density, for example. And it's a compressible fluid, not like water, which is a fluid and flows, but air actually responds to changes in density too. You can squeeze it and everything. So in my car, the balloons went the wrong way. Does that mean air has mass? I thought air was just like this drifty, misty thing that was all over the place, but it has mass and momentum. Yes, it does. Yeah, it has both of those things. So remember when you're in the car and you accelerate, you feel like you're being pushed backwards. And the ambrosia rolls to the back of the car. Right, yep. And but in actual fact, the car is moving forwards and you feel that force against you, so it feels like you're being pushed back. Okay. So when you start the car, the air actually moves towards the back of the car. The balloons go forward. And the balloons are lighter than air, so they sense the lower pressure and move towards the lower pressure in the front of the car. Okay. Hey, here comes the theme now. Maybe she, welcome to your birthday party and happy birthday. Hi guys, welcome. It's so great to see you. Good to see you too. This is gonna be a great day. We were just chatting about these helium balloons and meteorology and air and stuff and weight. And maybe you could tell us a little more about how this affects weather. Absolutely. You know, we're surrounded by air. It's just the fluid and any air that's less dense and more buoyant will go up. Like the helium in these balloons are like hot air and hot air balloon or warm air into a cloud. Any air that's more dense will fall down or slosh out of the upper parts of the atmosphere. So you can have down drafts that slosh out of a thunderstorm and get hit by that cold wind as the storm's coming in. Oh, that could be dangerous. They can be dangerous. They can cause some destruction, but it can also give you a nice cool breeze before rainstorm as it comes in. Oh, okay. Yes. So in my car, things were sloshing around. Kind of, how does that work? Hmm, let me show you. Okay. It just happens I have a bottle of nectar here on the floor. Okay. And you see, there's a bubble in the bottle. Right. At the top. And so if I move the bottle forwards, the bubble initially moves forwards because the liquid moves to the back and then eventually it moves back to the middle again. So let's try that again, move this way. Yeah. See, yeah, the bubble starts here and then moves back to the middle because the fluid is all getting, the more dense fluid is all getting pushed to the back. So Athena's helium balloons are the bubble. Yes, essentially. Oh, okay. That's where they're to the there. They're a bubble in the air. Wow. Well, that's pretty neat. That's a cool experiment. You could do it at home. I like that. Well, I think I smell something in the distance. Maybe the barbecue's ready. I can't wait. Shall we go off to the party? Absolutely. All right. Let's do it. Thank you. That was so fun. Wow. Such a cool experiment. I love that you just noticed something happening and you looked into it. That's just the most fun part of science, isn't it? Yeah. Absolutely. So there are a couple of questions that have been coming in and we'll welcome anybody else who wants to ask questions to go ahead and enter them in the Q&A or in the chat. The first question that we've got is what eventually happens to the helium when you pop a balloon? Well, it escapes from the balloon and it mixes with air and but the molecules are lighter. So, Jeff, maybe you should take it from here. Yeah. So actually a lot of the hydrogen and helium in the atmosphere got lost. They got out of space because they just go up into the air and sooner or later, since they're lighter than the air molecules, they just kind of go fast enough that they disappear out of the top. I'm glad somebody asked that. I was going to bring that up. Yeah, that is a great question. We've got another good one. So do cold temperature inversions really slosh back and forth? Yes, they do. Cold temperature inversions are really common in the front range in the winter where we get cold air down in the valleys between the mountains in the winter and the cold air will slosh up the sides of the mountains and down and cause clouds and fog at the top of the inversion. It's really very beautiful. So from high on Mount Olympus, I looked down in the valleys and I see some sort of smoke or smog or something down there. Is that a cold inversion? Not always. Sometimes there's warmer temperatures above that cause a stable layer above the boundary layer that can trap air as well. And sometimes it's just a lot of pollution near the surface because that's where it's coming from mostly. I think it's so cool too to think about how air acts like a fluid. Just that whole idea is just really cool because we can't see what's happening in the air but then sometimes we can use a fluid like water or maybe ambrosia to observe how the air acts even when we can't see it. Absolutely. And we can use that same type of physics for fluids in the air and use that to make our weather models and climate models that we use to forecast weather and climate with here at Incarre. So this is something that ties into what you've been talking about with helium and helium, what it does in air. Somebody asked what happens when to a balloon when you let go of it? And I suppose that depends on what the balloon's filled with, huh? So if it's filled with helium, it's gonna go up and up and up but the air gets thinner farther up so the balloon's gonna get tighter and tighter. I'm not sure if it's gonna pop or what's gonna happen next if it's a balloon that expands. The same thing will happen to just about any balloon. Doesn't matter exactly what it's filled with because the balloon will always try to reach its level of neutral buoyancy, the place where it's the same density on the inside as it is on the outside. And sometimes a balloon has to go far up in the atmosphere like the weather balloon to reach that level. Sometimes it never reaches that level. Sometimes it pops before it gets that high. Eventually the air will mix in through the balloon. It seems like it's a pretty impenetrable barrier but it's not and molecules can go in and out through the balloon and once it mixes enough it will become less buoyant and fall back down. And I've found quite a few wrinkled up old balloons in the woods over the years. It's kind of one of the reasons why people suggest you don't release balloons too much because they will come back down and be littered somewhere. Mm-hmm. Now we saw drops in rocket zons earlier this morning. Are there balloon zons too? Yes, absolutely. Weather balloons are shot off twice a day all over the world and those carry weather instruments up into the upper atmosphere to take measurements all the way up. And there's just a picture. And you can't come across those. Sometimes they fall down in places where you'll find them out in the wilderness and if you pick them up often they'll have a address on them where you can mail it back to so that it doesn't stay as litter. So kind of in the theme of buoyancy and things floating and flying in the air and of course we just finished with our tour of the aircraft, the research aircraft. Violet is wondering do airplanes use wind to fly? Yes, pilots try to follow the jet stream and get into the jet stream because jet stream is a bunch of very rapid wind, very rapid air and once they sit in that they can fly and they can go very fast in that. So their ground speed is, I think I've heard that there's actually measured ground speeds faster than the speed of sound but that's not in the air. So they can go really, really fast as long as they're in a very fast jet of wind. I see. Okay, I'm looking for any other questions. Those were some good questions that we had this afternoon. Those were great questions. Got a bunch of curious folks out there today. I don't see any other questions coming in right now. So while we're waiting, do you guys know where we get our helium from? This might surprise you. I don't know where it comes from. Oh, so actually get it out of the ground, funnily enough. So a lot of minerals are radioactive and so when they decay, they give off alpha particles which are essentially helium nuclei and then the helium nuclei pick up electrons and become helium gas. And so there are big reserves of helium actually underground and it's mined and then they bring it out and actually it's getting a little scarce right now. So there is like a worldwide helium shortage. But it's actually pulled out of the ground, funnily enough. You wouldn't think that. Something so light. So it comes from rocks. It comes from rocks basically, yeah. Air from rocks. And then like in Boulder, we have a lot of radon gas. So that also emits helium. We're worried about atom-based ones, yeah. The helium is part of the nuclear decay. Yes, exactly, yeah. So the big atoms split into two small ones, yeah. I know, I tried to go and get some balloons recently for a birthday. Unfortunately, I missed your birthday, Athena. But I heard about this too, the fact that there's a shortage of helium right now. Yeah. Yes, a lot more scarce and a lot more expensive. Oh, somebody, John just sent a message saying, was there some new helium discovered recently? Hope so, yeah, I haven't heard about that, but it's quite possible, yeah. Hopefully, that'll help the shortage. Yeah, because we use it in the lab and things and it's become really expensive. Well, it looks like there's one more question. This is a very important question for everybody to know. Zeus, can you fly? Mercury is better at flying than I am. He has little wings and shoulders and stuff like that. So he's better. I just kind of leap and soar and stay on the clouds and tromp around and shake the earth with my big feet. There. I don't know if you saw earlier that my hair here is like a cloud and so it comes from cumulonibus clouds and so I'm a living, walking, breathing demonstration of meteorite. Thank you so much. We've got one more. We've got great questions coming in and one more question as we were kind of talking about all of these issues with helium. Somebody's wondering how do we find helium? Jeff, do you wanna talk about how we find helium? I don't know really how do we find it. I think it just comes from mines and things like that but I don't know if they go look for it deliberately or if it just comes out when they find coal. I think about a big funnel over the ground and let it go up through the funnel because it's gonna catch the air. You probably have to look for very specific rocks and we have a lot of different tools that we use to measure the different gases in the atmosphere around us. And so there's a good chance that they measure the atmosphere in different parts of mines and look for those gases using those instruments. If people were watching earlier, we had instruments that measured the carbon dioxide in the atmosphere that we use here at NCAR and a lot of different industrial usage probably have, excuse me, probably have instruments that identify helium and hydrogen and other underground gases. Sounds good. And that is a perfect segue to take a quick break before our next session which is all about that instrument for measuring carbon dioxide. I'm glad you mentioned it. So many thanks to Zeus and Poseidon and Athena for joining us today and happy belated birthday, Athena. Thank you very much. Thanks for joining us everybody and in just a few minutes, we will be back to explore measuring carbon dioxide with that special instrument that Athena mentioned. So hopefully we'll see everybody soon.