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Uploaded:2015-06-25
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So... what makes the wind? You might be surprised to learn that it has to do with two of Earth's spheres; The Hydrosphere and the Geosphere. In this episode of Crash Course Kids, Sabrina takes us to the beach to chat about how the wind comes into being and why that's pretty darn awesome!

This first series is based on 5th grade science. We're super excited and hope you enjoy Crash Course Kids!

///Standards Used in This Video///
5-ESS1-2. Represent data in graphical displays to reveal patterns of daily changes in length and direction of shadows, day and night, and the seasonal appearance of some stars in the night sky. [Clarification Statement: Examples of patterns could include the position and motion of Earth with respect to the sun and selected stars that are visible only in particular months.] [Assessment Boundary: Assessment does not include causes of seasons.]

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Credits...

Executive Producers: John & Hank Green
Producer & Editor: Nicholas Jenkins
Cinematographer & Director: Michael Aranda
Host: Sabrina Cruz
Script Supervisor: Mickie Halpern
Writer: Kay Boatner
Consultant: Shelby Alinsky
Script Editor: Blake de Pastino

Thought Cafe Team:
Stephanie Bailis
Cody Brown
Suzanna Brusikiewicz
Jonathan Corbiere
Nick Counter
Kelsey Heinrichs
Jack Kenedy
Corey MacDonald
Tyler Sammy
Nikkie Stinchcombe
James Tuer
Adam Winnik

 Introduction 


Here's a riddle for you: What's something you can't see, but something you can feel? I'll give you a hint, it sounds a bit like this - *Woooshhhhhhh*. Hold on to your hats because today we are talking about wind. 

(Intro music)

Last time, we learned about how the land absorbs more energy from the sun than the water does, and it turns out this unequal heating of the Earth's surface is what produces wind. You heard me. Wind is part of the atmosphere, but it's often caused by two of the other spheres - the geosphere and the hydrosphere. Remember those? But what exactly is wind - and how does the sun's energy create it? 

 Big Question 


Well, wind is air in motion. It's the flow of large amounts of air, usually from a high pressure area to a low pressure area. When I say pressure, I mean the amount of force that air in the atmosphere puts on an object. 

On Earth, which I assume is where you are right now, how much pressure the air exerts on stuff mainly has to do with its temperature. Specifically, cool air produces high air pressure, and warm air produces low air pressure. 

So, with all that in mind, let's take a look at how the hydrosphere and the geosphere can work together to create wind. A good place to start is that same beach spot we visited in the last lesson. There you'll remember the land absorbs more of the sun's heat, so it has a higher temperature. Those warmer land forms heat the air above them and that hot air has lower air pressure.

Meanwhile, the nearby water absorbs less heat and is cooler, so it heats the air less and creates higher air pressure. When those two environments with different temperatures and different pressures are basically next door to each other, air rushes from one place to another, to try to balance out the differences. 

You and I call that rushing air, wind! Does this wind cycle stay the same all day, every day? Nope! But it does follow a pattern, and if you want to see how that wind cycle works, well, I hope you packed your jammies, 'cause we're going to have a sleepover on the beach. 


 Investigation 


Here's our little beach during the daytime, with the hot sand on one side and the cool ocean right next to it. When the sun's shining down on it, the land heats up faster than the ocean. The warm air over the land rises and the heavier, cooler air from the water rushes in to take its place. This causes what's called a sea breeze that blows from the ocean onto the land. 

But what if you visit the beach at night? During the evening, the land will cool down faster than the ocean, and the opposite cycle will happen. At night, warm air over the water will rise and the heavier, cooler air from the land will blow out to the ocean. This is called a land breeze. 

This model is just one example of a common wind pattern. There are different kinds of winds all over the world but for the most part, they follow patterns based on what conditions are like nearby. 

 Conclusion 


So, wind isn't just air randomly moving from one place on Earth to another. It's the movement of air that follows a pattern, usually blowing from high pressure areas to low pressure areas, and these patterns are caused by uneven heating on the Earth's surfaces. 

But while this model we created might look pretty tame, don't be fooled. Wind isn't always just a gentle breeze, the fastest winds on Earth occur inside tornadoes, where they can reach a speed over 400 kilometers per hour. And that's nothing compared to wind on other planets in our Solar System. Neptune has winds that can gust up to 2,000 kilometers an hour. 

Wind can be a really powerful force of nature. I guess you could say I'm a big fan. And sorry if you got sand in your jammies but it was worth it to learn about the wind, right?

(Outro music)