Making Cloud In Bottle With BTN

So I'm joined by the wonderful Tina Donaldson. She is a meteorologist for the Bureau of Meteorology. Yeah. Thanks for joining me, Tina. Thanks for having me. Welcome to BTN Live. Happy Friday, everyone. I've hope you had a good week and make sure you send in your questions for Tina because we'll go through them throughout today's episode.

But yeah, do you want to talk a little bit about your job and what you do? Yeah. So, I'm a meteorologist. So, I help people understand the weather. We look at all of our observations and our models and package that up into a forecast that people can use for whatever they're doing today. There you go. Very cool. So, should we go straight into the first question? Let's get into it.

All right. Leila from White Hills Primary School has asked a few different questions. The first one is, how do clouds float even though they can be full of heavy water droplets? Yeah. Well, that's right. So, they are made of water droplets, clouds, but they're actually just so tiny and light that the air can just sort of hold them up. So, a cloud forms when you've got, say, hot ground and the air above that's rising. As it rises, it cools and condenses. And that rising air is just enough to keep the water droplets suspended in the air. And sometimes they grow bigger. So, they might have more water condense onto them or they might bump into each other and um and get bigger and bigger. And then when they get so big, they fall to the ground as rain. Exactly. Oh, we got some rain happening here. There you go. It's raining inside.

Love it. An extension of that question. Leila also wants to know why rain clouds can go grey and not just white. So, a lot of clouds are white, so the sun putting light onto the little water droplets scatters out and it comes out just as white. But the thicker and denser clouds, they start blocking out some of that light. So there's less light that can get through and that's why some of those bigger clouds or thicker clouds look grey. So it's a bit like they're causing shadows. Got it. So it's not dirty rain water. It's not dirty rain. No. And the clouds themselves aren't different colours. It's just that they're blocking out more light. Yeah. They just look like that.

And then final question from Leila. I'm letting her get a few because I'm also interested. Is "what makes a rainbow appear when the sun shines through the rain?" Do you know much about rainbows? Well, if you can tell I do. I thought you may because of the earrings. I like rainbows. I wore my rainbow earrings. Special today. Special occasion. Yes. So, a rainbow forms like Leila said when you've got, maybe some rain moving away and there's maybe still some water droplets in the air from that. Now, light that we see is actually made up of all colours of the rainbow. So even white light has all the colours there. But when that white light goes through a raindrop, the different colours get split out into the rainbow. And that's how we get these beautiful rainbows. So cool. They're amazing, aren't they?

Kane has a very funny question. Kane from Evansson School asked, "Why is the weather always so windy and rainy every day?" Well, it depends where you live, I guess. Sometimes, you might get some places that just always get a sea breeze and so they're always windy in the afternoon. Some places are quite calm though, especially if you go further inland overnight, the wind sort of like calms down. So, it really depends on where you are. Some places are definitely windier than others, though.

I think this might be a good time to do a little experiment that Tina brought in for us today. We've got on our table here at BTN Live a little setup to do some clouds in a jar. Do you want to talk us through what experiment we're going to be doing?

Should we try and make a cloud in a jar? Very cool. That might help with the rain explanation of it all. Rain and how the clouds stay up in the air. Okay. All right. What do we need to do first? All right. So, I've got the ingredients to make a cloud here. So, I've got some warm water here. So, the warm water helps because warmer water will evaporate more easily and turn into vapor. Now, as the air rises up in the atmosphere, it's cold. Yes. So, I've got some ice to try and make the top of my jar cold. And then my secret ingredient today. Okay. What's this? Hairspray. Hairspray. Okay. Yep. So, this is going to form what's called condensation nuclei. So, we need the water vapor to be able to condense onto something. So, this is going to form just little bits of dirt essentially for the water vapor to condense onto. Got it. Okay. But in real life, it probably wouldn't be hairspray. So, in nature, it might be dust or pollen. Any of the things you'd find outside. That's right. Just little bits just floating through, you know, smoke, things like that. Okay. So, should we give it a go?

Let's do it. All right. So, we've got our jar. Got our jar. Our hot water. Hot water. All right, let's pop that in the jar. Cool. What do you reckon? That'll probably be enough. That'll do. Okay, that'll do it. We'll give it a bit of a swish around here. All right. The ice over here. All right. As you can see, we have our ice. Yeah. And actually, you can see it's already starting to condense on the inside of the jar, but I want it to condense on my condensation nuclei.

So there we go. So we've given it some condensation nuclei. I'm going to make it cold up here now as well. So try and pile some ice up. Ice on the lid, hairspray, and hot water in the jar. That's right. We'll see how it goes. We'll see how it goes. So, bit of an experiment. So every day it can be a bit different because of course the temperature and the humidity and the air itself changes from day to day.

So it could do different things. Look, I think it's showing up quite well on there, especially with the black there. So, you can see a cloud starting to form inside the jar. Wow. Our own little weather system. And so, if you look, you can actually see sometimes it sort of swirls up and down. You know, you've got the hot air rising, then it hits this cold lid. And it can come and drop. So, even just that little bit of air movement in there is enough to keep those little water droplets just moving all around. Super cool. And is this something that any student who's watching this could try at home? You could do that if you got a jar, some hot water, some hairspray. That's all you really need.

Will it change based on how big your jar is? Could you do this in a really big jar? You could do it in a really big lid and lots of ice. Okay. Yeah. So, just a would need more things. More things. If you wanted a really big cloud. It's actually going quite well now. There you can see it sort of billowing down as well. So, it's getting up there. There's our cloud. Yeah. Wow. Well, I'm quite happy with that, actually. I am too.

Did you want to touch the cloud? Because we can even have it. Oh my gosh. Yeah. I can see it coming out now that we've lifted the lid off. There's our cloud. So, all that's coming out of the cloud, out of the jar now. And all we have in there is, oh, wow you can really see it on the camera. All we have in there is some hairspray and some water. Water. That's right. Wow. And it's formed a cloud. Yeah. So, that will come out. It'll just evaporate now because the air actually is a bit drier. It's different. Yeah. Very, very cool. Turned out well. Fun little science experiment to start the show off. Hey, that's awesome. I love it.

If you have any questions about that, make sure you send them to us and we can go over them before the end of BTN Live today.

All right. Next, we have a question from Brielle from Maitland's Christian School. Um, Brielle is an aspiring meteorologist and she wants to know how you got in the field. Did you have to do any sort of study to do this job? And where can you do this job? Can you be anywhere in Australia, anywhere in the world?

Yeah. Well, great to hear that there's an aspiring meteorologist out there. So, I got into meteorology in high school when I thought, what am I going to do when school finishes? I need a job. And I found out that to be a meteorologist, you got to be good at math and science. And lucky for me, they were two of my best subjects at school. So I kept on studying math and science at school, went to university and did science at uni. And then when you've completed that, you can then apply to say the Bureau of Meteorology and do a one-year intensive training course where they teach you all about the really nitty-gritty science of how the weather works and all our systems.

Yeah.

Wow. Very cool. What kind of maths and sciences would you do in high school that could be helpful if you want to be

a meteorologist? Algebra. There is bit of algebra. Any equations that really they pop up a lot in your day-to-day work. Well, a lot of the computers sort of take care of a lot of that these days. Yes. But you still sort of need to understand how it all works so you can interpret it correctly. Yeah. Bit of geography doesn't go astray as well actually. Of course.

And then this is something you can do from anywhere in the country if you wherever you live in Australia. Well, I'm based in Adelaide with you and we've got an office here in Adelaide. The Bureau of Meteorology's main office is in Melbourne, but we've got offices right across the country in every capital city. We've got them in some really remote places as well like Giles in outback Australia, Willis Island. We've even got offices in Antarctica and I've worked down there as well forecasting the weather for Antarctica. Super cool. That would be awesome. Um so yeah, you help forecast and look at the weather everywhere then. Everywhere. Yeah, that's right. Very cool.

Mia from Lindhurst Primary School has asked, "How does the weather change around Australia?" Which is kind of similar to Kane's question of why is it so windy and rainy all the time?" Yeah, it depends where you are and so Australia is really big, right? Massive. Yeah. So down in the south where we are, we get a lot of cold fronts move through and high pressure systems and the weather sort of changes a lot. But when you get up into the northern parts of Australia, they've got more tropical type weather. So we've got like winter, summer, autumn, spring. Up there, they're more like wet and dry seasons. They're closer to the equator. They get really big tropical systems move through there. So, really different. So, it sort of depends on where you are, how far away from the equator you are, how close to Antarctica you are. And also we talked about geography. So, maybe you're up in the mountains or down near the beach or things like that. So, all of those things can influence the weather as well. Lots of different factors at play there. Absolutely.

Daniel from Upway High School has asked, "How does the BOM predict the weather?" And they asked specifically how do they do it using supercomputers? Does the BOM use supercomputers? They do use supercomputers. Oh, that's pretty cool. Way too many equations for me to calculate on my own or even with the whole team. Okay. So, how do we predict the weather? So, we start by looking at what's happening now and what's happened in the past.

So, we've got a whole heap of different observations that we look at. So, we've got all different weather stations around the country that look at the temperature, the humidity, the wind speed, the pressure. Then we've got things like radars that can see the rain at the moment and we can track that going through. Then we've got satellites way up in space that are taking photographs all the time, so we can see the clouds and how they're moving as well.

And then all of that information goes into a computer model. And then all those special equations we talked about that know how the atmosphere moves and then it try and then it will predict what the weather's doing and then a meteorologist can look at that and turn it into a weather forecast.

Wow, pretty cool. Would those things like what we have in space and whatnot would they be Australia's ones and then other countries would have their own? How does that sort of work? Lots of different countries have satellites up there. Yeah. So, we actually use a Japanese one because they're on a similar location near to us .Not too bad of a flight over. That's right. Yeah. So, we can use their satellite because it's sitting right over the same sort of spot of the Earth. It's got a good view of Japan, and good view of us as well. Very nice. That's super cool. And then, yeah, supercomputers. Wow, that's awesome.

Sophia has asked a really interesting question. It's been popping up a bit in the news. Some of you guys might have seen the Bogong moths and the weather has been having a bit of an interesting situation. She's asked how are Bogong moths affecting the weather systems and is it having an impact on businesses?

Oh well, I don't know about businesses, but our radars are picking up the moths. Yeah. Yeah. So radars just work by putting out a little pulse of energy and then it will hit something. It's designed to hit like just, you know, a raindrop, see the raindrop, and then bounce back. And then depending on how long it takes for that pulse of energy to come back, we can tell how far away the rain is or, how big the raindrops are and things like that. But of course, raindrops and moths, similarish sizes. Yeah. Well they're a bit bigger, but it can pick up any sorts of things.

So yeah, radars often pick up insects, moths. In Adelaide, they can actually even pick up the bats in the botanical gardens when they sort of migrate. So yeah, so the radar is just seeing them at the moment. And so on some of the radars, it might look like it's rain, but if you go and have a look at the satellite picture or the, you know, there's some other clues going around, we know that it's not really raining. It's just the moths. So the radar is just picking up the moths. And that's because there's a big group of these Bogong moths migrating at the moment. That's right. They seem to be going around. There's a lot of them. Yeah, a lot of them. Particularly through eastern parts of Australia at the moment.

Yeah, because then what about other things that are normally in the sky like birds and whatnot? Do they have an impact on the radar ever? Oh, maybe not birds, but yeah, they're too big. They're too big. Yeah. But like often see a lot of insects can be picked up by the radar. Something interesting we even had some space debris. I don't know if you saw a few weeks ago there was something up in near Townsville and we could even pick up little bits of that space debris on the radar. So you can pick up any tiny little bits that might be floating around through the atmosphere. Yeah. But the moths, are they specifically causing perhaps a little bit of mayhem because there's so many? Is it the scale? I think maybe there's just a lot of them at the moment. Yeah, that makes sense. Great question, Sophia.

Henry just said, "Hi." Hi, Henry. We have a question from Chloe, who's asked something I don't think I know all that much about, but Chloe wants to know, "How do the spoon thingies on the roof work?" Do you know what Chloe's referring to when she says spoon thingies? I reckon I know what Chloe's talking about. And in fact. What are these? We have one right here. We have spoon thingies. Okay. Yes, that does look like a spoon. It looks like three spoons actually. Three spoons in fact. All right. What is this? Yes. So you do see them around. A lot of buildings have them actually. And they are to measure the wind speed. Yeah, that makes sense. There you go. So a lot of buildings will have them because people will just want to know what the winds are doing around on their own building.

But of course this forms part of our observation network that we talked about before when we were saying how do we predict the weather? So we got lots of observation sites all around Australia. And most of them will have an anemometer this is called, something to measure the wind. Yeah. So obviously the faster it's spinning around we can tell how fast the wind speed is. Very cool. So not a spoon thingy is called an anemometer. Correct. Fabulous. And while we while we have it up, what are these little bits underneath mean? Well, here we go. underneath we've got different ways of measuring it. So we've got yeah km/h is how we usually measure it and also m/s and knots. So a lot of people use knots like mariners or pilots use knots. So depending on what you're after we can measure it. Very cool. That would be handy if you were perhaps trying to sail and whatnot. Exactly. Yeah. Good to know the wind speed. Very cool.

Antonio from Chatswood Public School has asked, "Why does it rain more near the equator?" Ah, it's a good question. So, near the equator, when it's hot, hot air can hold more moisture. Remember when we made our cloud, one of the key ingredients was water. So, near the equator, it's hotter, there's more moisture available, and the atmosphere is thicker. So, that's one of the main reasons why it rains a lot more near the equator. Good observation. Very good. I didn't know that either. So, fun little fact for today.

And then Nate has asked, "How does a weather forecast actually know if it's going to rain or storm?" How does it know these things? How do we know these things? Oh, well, so we are relying a lot on our observations. So, we'll look at let's say we're forecasting rain. We want to know is it really raining? I'm not actually there. I'm forecasting for over there and I want to find out. So, there's a few clues. So, we can see if we've got a radar over there and look to see if our radar has picked up any rain. We've also got a good rain gauge network right across the country as well.

Um I've got a little rain gauge even, should I show this one? Absolutely. Let's do it. So this is this is a bit of an old fashioned one. We used to have, we still do, have a lot of volunteers that go out there and monitor the rain for us. So this will sit in a little rain bucket and collect the rain and then we can see how much has rained as well. So you can see all through here. So we like to measure rain in mm. Yeah. So it'll fill up and they'll tell us, oh no, we've only had .2 of a mm today or you know maybe we've had 13 mm quite a lot.

So, would that then get emptied and put back out every single day or how often would that get checked? 9:00 a.m. every day. There you go. That's historically what it's been. We like to do the weather at 9:00 a.m. Very simple. Very nice. Good little routine.

And then I guess a lot of the predicting would be based on maybe looking at history, looking at patterns, what's happened before. Exactly. Yeah, that's right. So, we'll have weather models of course that help to tell us when it rains. But yeah, historically, we might know that when the wind's blowing a certain way, it likes to rain. When the winds come onshore in a certain direction and things like that. So, there's a lot of local knowledge and observations that come into it as well. Super cool. Love it.

Class 5B from Oxley College has a really interesting question. They want to know if you think whether humans could ever control the weather. Oh wow. Well, yeah, people try. That's right. Yeah. So, back to our little our jar cloud in the jar experiment. So, some people try to do what's called cloud seeding. So, you know how we got our trusty old hairspray there because that helps to make the cloud. So, what some people do to try and promote rain is they'll put extra little particles in the air to help to make the cloud, the cloud gets bigger and bigger and then it will rain. Yeah. So, there are ways that people try to control the weather. Handy tricks. Yeah. But ultimately, mother nature will just do what she likes. It's going to do what it's going to do. Yeah. Fabulous question though. Very interesting.

We have another question from St. Mary and Chris High asking, "Is it is it hard to predict the weather? Is this a tricky job to do?" It can be tricky sometimes. Yeah, that's right. Like for instance, even if there's showers coming across, one suburb might get a shower, but then the person in a suburb or two over might not get a shower and they'll be quite disappointed that they missed out on that shower. So sometimes it can be quite tricky. And of course, when we're forecasting the weather, the further out you go in time, the harder it gets. So that's why we always tell people stay up to date with the latest forecast and warnings. So check up on the website or the radio, whatever it is where you get your weather from because if we see that maybe there's been a bit more rain, we got an observation that the rainfall was actually higher that might change what the forecast is. Yeah. Yeah. Absolutely.

Then we have another question that you sort of kind of did speak to just then. So I'll ask it while we're here is "does the weather change throughout the day?" Yeah. So, yeah. Yeah, it does. I mean, some places have four seasons in one day. You might have a cold front come through where ahead of it it's nice and sunny and warm, but then you have the front go through and it's raining and windy and terrible and then the front finishes and carries on through and then it's just maybe a bit cold and sunny and dry behind it. Yeah. So, it can change a lot. Yep. Very cool.

And then we have Lacy from Fig Tree Public School. Who wants to know, do you know the exact time it's going to rain and can you work that out? Oh, well, closer to the time, the closer you are to it, sometimes. So, if you're looking at the radar, you know, the radar scans, well, depending on which radar you're using, maybe every six minutes. So you might be able to track, oh, you know, I know that this little cell's moving so fast and so then you can sort of predict where it's going. So sometimes if you're, you know, within a certain period, you can predict when it's going to rain. But the further out in time you go, the broader we generally have to be about when it's going to rain. So we might sometimes we might be able to say morning or afternoon, sometimes we might just say anytime during the day. So it really just depends. Very cool.

And then we have a question from Alira from Noora High School and they've also asked a similar question to Jackson from St. Mary's Primary School. They want to know how do we get thunder? How do we get thunder? Yeah. So, thunder is what you hear when there's lightning. Yes. Of course, lightning from a big thunderstorm. So again, we got our cloud. So thunderstorms, really, really big clouds this time. And the bigger the clouds, the ones that go really high up, they've actually got ice crystals in them. Oh, okay. Yeah. So, the ice crystals sort of like bump into each other and make a bit like static electricity. You know how you get your balloon and you rub it and it makes your hair all sticky upy? That's the experiment we could have done. Yeah. So, then you've got these, static electricity in the air and then it wants to create a lightning bolt somewhere. So, maybe to another cloud, maybe to the ground. And it's that lightning bolt that makes the sound of thunder. Right. Yeah. So, it's actually really hot this lightning bolt. And heats up the air around it and that's what you hear. Wow. Sort of air contracting around the lightning bolt. That is pretty cool.

Room 9 from West Beach Primary School has asked a really lovely question. What is the most exciting part of your job? Oh, I've got so many exciting parts of my job. That's nice. Depends what I'm doing every day. I mean, the weather changes every day. I love forecasting thunderstorms. I don't like being in a thunderstorm myself, though. But they are fun to forecast. How come? Is there a reason why there's the most exciting? Is it because it's the biggest weather event? Yeah. I mean, you can look at the radar and see all different sorts of radar signatures, things like that. I mean I do love communicating the weather and talking about the weather as well. So that's why I'm happy to come here today and experience that. Yeah, exactly.

Jackson's question was sort of asking why thunderstorms happen. Can you expand on that perhaps? Oh why thunderstorms happen. Yeah. So the ingredients for a thunderstorm, similar to a cloud, we need some moisture but we also need what's called some instability. So something that's making the air rise really quickly. So it might be say a cold front that's pushing the air up really quick or maybe it's really hot down on the ground but really cold up high and so the air is rising super quick. That gives you the chance for this really big tall thunderstorm cloud to form and that's when you get that static electricity. Makes sense. Very very good.

Uh what else do we have? Oh, Willow from Wollongong State School, I hope I said that right. Um, has asked, "How can meteorologists predict the weather in like seven days? How can they see so far in advance?" Yeah, when we get to seven days, we're relying a lot on the computer models at that point. And so, it's not just one computer model either. There's lots of different ones. So, we'll look at them and think about, what's the most likely outcome? Which computer model is doing the best at capturing the situation right now and put that into a forecast. Yeah. So beyond seven days it does get a bit tricky actually. Yeah. And to be honest, you're probably almost better off flipping a coin I think. Yeah. So that sort of starts to reach the limit of where you can go with those sort of forecasts. Very good.

And then Hiro from Riverton Primary School has asked, "How do weather balloons work?" Oh. Do you want to talk about weather balloons? Something we haven't spoken about. Well, in fact, I even brought one along. Great. Fabulous that you asked this question then. Let's have a look. Let's have a look, shall we? Okay, great.

This is a fresh one. So, it's still covered in just talcum powder, but they are massive, massive balloons. Much bigger than your normal balloons. So, this one it's bigger than me. In fact, when you blow it up, it would be much much bigger than me. Wow. We fill it up with hydrogen. So hydrogen's light and so it can rise up really high into the sky. In fact, they go like 20 or 30 km. And then underneath the balloon. Oh, we've got more props. Yeah, more props. This this sort of hangs off this.

Um and this can measure the temperature and the humidity and it sends all of this information back to us on the ground. Wow. Very cool. And of course the wind will blow that around as well. So from the weather balloons we can get temperature, humidity, wind speed, wind direction, not just on the ground, but yet all the way up to, you know, 20, 30 km above us.

Wow. Yeah. And that also feeds into our weather models because it's important not just what's happening on the ground, but right up through the atmosphere as well. That is so cool. They must be huge. Yes, they are. They are massive when they're blown up, bigger than me. Yes. Super cool. Okay, there's our weather balloon up there for you to have a little look at when they're all blown up and big. There you go. Yeah. So, that person's wearing some protective gear at the moment because we fill it up with hydrogen. So, you have to be quite careful with those. Um Yep. And it's got a little target underneath there as well, so that can sort of lock on when it's sending it signal back and get all of that really important information back. Wow, that is so cool.

Well, thank you everyone so much for your questions. This has been a very, very informative BTN Live. It's been great having you. Thank you so much, Tina.

Next week for BTN Live, we're going to have a firefighter come in and chat to us. So, make sure that you keep a lookout for that and make sure you send in all of your fabulous questions for them because that's also going to be a very exciting episode. Um, but a few little shout outs to everyone who tuned in. So, we've got Laila, Mia, Daniel. Shout out to all of you, Morgan, Laura, Charlie. Thank you so much for tuning in this week. Um, and yeah, thank you so much for coming in and teaching us so much great stuff. Thanks for having me. I've loved all the questions. It's been a great episode. Thanks everyone. Bye. Have a good weekend.