[Music] hey everybody it's first waren Storm Team chief meteorologist Brad penovich hope you're having a great Wednesday today's topic is going to be brought to you by Chris M and it's convection currents they're just not for cooking all right that's a bad weather joke but um convection curs are something we use for cooking but they are really cool and they happen in a lot of media just not the atmosphere just not your oven also deep in the Earth's crust and today Chris M is going to explore the topic of convection currents it is really cool it explains a lot of things that happen with weather in the atmosphere specifically wind a day like today would be a good example of that wind starting to pick up so with no further Ado let's go to Chief or not Chief I say meteorologist Chris M A lot of C's there a lot of a lot of se's alliteration there convection currents it sounds complicated but at the end of this lesson it's going to be easy for you it happens in the world around us starting in the Earth's crust in our oceans in our atmosphere causing wind thunderstorms and even clouds even in your own home a lava lamp is a convection current and a pot of boiling water is also a convection current through this lesson you're going to hear the words convection and current of bun so you probably should know what they mean convection simply is going to be a heat transfer by a movement of a liquid or a gas now this transfer of energy has to only happen in a liquid or a gas so example number one a pot of boiling water so what's happening is there's always going to be that heat source so that's going to be the stove top picture this like the atmosphere that when the sun is heating up the surface that heat rises just like the warm air is rising in this pot of boiling water it rises up to the top of the water it spreads out and event cools back down where convection is also going to be the mixing of that fluid or that air in an atmospheric viewpoint but as soon as that rises and Falls Rises and Falls water starts to boil once all that water has mixed up to a certain temperature or 212° F but I actually need this for demonstration number two here is demonstration number two for this we have some boiling water we have three coffee mugs that are the same I have this tub that filled with lukewarm water or room temperature water and then lastly I have these big things these are pipe BS most likely you don't have these hanging around your house but you're going to see why I need these and also you need some red and some blue food coloring so let's start this off right let's get the red food coloring so what I'm going to do I'm going to take the pipet and we're going to illustrate with this this experiment Rising warm air and how the cold air is going to be replacing it or in this case Rising warm water replaced by colder water so check this out get that out let's get the air out there we go we put this one in the middle squeeze it right there so that's going to illustrate our warm water number two we'll get our Blues feels like a legitimate EXP expent right put it down do it again all right now we get to watch with everything happening lastly pour some boiling water in this coffee mug mug number three put it underneath and let's see what happens this is absolutely mesmerizing and I understand if you're just zoned out watching the different changes of the colors but there's a lot of science here and it's actually pretty cool so convection simply put is the red right there that's convection convection is just the pocket of rising air or water in this case that moves to a cooler area and then once you get the current going that is that convection current so what's happening is you have all that heat moving to one place but it doesn't just leave an empty spot behind more water needs to take its place now the Earth weather always needs to be in what's called an equilibrium so that's a balance so that's why that colder air or that colder water in this case is moving back in but then that hot water eventually reaches the top because more and more of that warm water underneath it is driving it upwards but then in the meantime that cooler water which is a lot more dense sinks back down and it continues to repeat itself and as I showed you at the beginning this is very much what happens in boiling water these big ovals that are forming from the change of that warm Rising moist air to the cooling dry air that happens in the atmosphere that's a convection current and what's really interesting that's exactly what happens in thunderstorms so let's take that example and learn a little bit more about thunderstorms what you're looking at right now this is a classic supercell thunderstorm or just a thunderstorm in general as we're going to be focusing on the upper parts of this so that water line that I was showing you notice how the warm water had to spread out on the top well the reason for that is because it can't go any further but the same thing happens in the atmosphere there's something called the tropopause the tropopause divides the two lower layers of the atmosphere between the troposphere where all of our weather happens and the stratosphere so it's at this point that Rising moist air can't go any further the only way it can is what's called an overshooting top that is that updraft keeps on driving so fast that it's able to just get past the line before it stops meanwhile everything else spreads out on the top so if you've ever seen a thunderstorm with an anvil the whole reason why is because of the density differences and it can't go any further and our experiment that we were just doing shows just that but the same thing happens in a thunderstorm once that warm moist air rises up eventually it has to come back down and other case that could come down is wind and rain but all in all it's a convection current and did you know thunderstorms are also known as convective storms because they form from rising moist waste air Which is less dense than surroundings if we think bigger there's another convection current that happens along our shorelines it's called a seab breeze what happens is the warm sun warms up the air and that rises that's the convection but eventually it moves towards the cooler air which is over the ocean or a lake that is going to allow for it to cool eventually drop as it descends and then it moves back towards the warmer air it's a constant current that happens and a lot of times through this you can even form some rain showers and even some thunderstorms right along the coast briefly this also happens on a global scale across the Earth the convection currents can create what's called trade winds or global winds that will steer ships and even steer hurricanes moving to our oceans convection currents the same thing happens that warmer water is replaced by colder water and this creates currents across the Earth and some animals even Cruise along these currents to get from place to place H right another example something you wouldn't think about right beneath our feet under the Earth's crust is What's called the mantle the mantle is just moving streams of molten rock that moves very very slowly this is what drives plate tectonics another couple examples just around the home a lava lamp now you might not know what a lava lamp is but they're really big in the ' 60s and' 7s I even had one when I was growing up but this is simple convection a convection current you need the heat source that light bulb is heating the material that is in the lava lamp it rises up eventually once it gets to the top of the lamp it cools and it drops back down and it continues over and over and over again in a current and when we're looking at convection it's also around a campfire when you see that Rising smoke from the fire that is also convection but what keeps us warm to complicate things isn't necessar convection but thermal radiation that is just that heat that is just being dispersed from the fire that's why if you have your face turn only one side of your face gets hot compared to the cooler side because it's the direct radiation from the fire that's hitting you around it well there you have it our experiment is now just a sea of purple because in essence convection is just the mixing of air or a mixing of a fluid so just like in the atmosphere that up down down around those ovals after they go on for a while air is going to be the same temperature in this case the water is the same color so when you go out and about you realize that convection currents are in the world around you and a campfire and a pot of boiling water and in our everyday weather thanks Chris yeah I love convection currs it's one of the cool things and when you see it happen in a thunderstorm that's why time lapses of thunderstorms are so mesmerizing because you can actually see the convection in the clouds and that's what causes a lot of movement and sometimes what people confuse for rotation in the storm is just the convection current remember rotation horizontally is what creates uh tornadoes up and down motion is typical in every single thunderstorm so we would expect to see that especially the up and down motion of roll clouds and uh shelf clouds so today's weather school I love it convection currents it's going to get a little chilly so we don't have as much convection though today we're going to see a couple popup convective showers as well as that cold there moves in a lot go to wcnc.com or YouTube and search for WCNC we've got a whole playlist with all of our past episodes which are now over two months of episodes pretty amazing so go check it out we'd love to have you check them out and see them again and share them with all your friends have a great great Wednesday