Bill Nye The Science Guy on The Atmosphere

If mountain tops are closer to the sun, why is it always colder up there than it is down here in the city? Well, please consider the following. Our atmosphere is thin, but it's thick enough to keep us warm. Now when you're wearing a coat like this one, it keeps you warm because it holds air next to your body. The same thing with the atmosphere. There's more air above us when we're down here in the city than when we're way up here in the mountains. So it's like the world's low places are wearing more coats. They're wearing more air than these places up high in the mountains. Now as you travel up through the atmosphere, it gets colder and colder because the air gets thinner and thinner. Until you're up around ten kilometers, that's when you leave the troposphere and enter the stratosphere. Anyway, the rate at which it gets colder is called the lapse rate. And it's about 5 and a half degrees Celsius per kilometer. So a mountain say 3000 meters high, let's see that's about 10,000 feet would be about 17°C colder than it would be down here in the city. And that's plenty cold enough for there to be a spring shower in the city while it's snowing up in the mountains. Thank you for joining me on consider the following.