Geological Formations

W: So yesterday, we started talking about how geological formations take a long time to be created. One of these formations is called the glacier. Does anyone know what a glacier is? M: It's a lot of ice! W: Well, kind of. It's certainly a lot of ice, but it's a little more than just that. A glacier is like a river of ice that moves slowly. The way a glacier moves depends on the slope of the land. A glacier will move with gravity. Okay, so we have to talk about how these glaciers are formed. See what happens is snowfall covers mountainous regions. And this snow never completely melts. But, it might thaw a little and then refreeze a little bit. So you have this thawing and refreezing which changes the snow to granules. Then more snow accumulates. Can anyone guess what happens to the snow that's at the bottom of this pile? M: Wouldn't it get really firm? From all the pressure? W: Exactly! So then, over thousands of years, from lots and lots of pressure, these huge sheets of slow moving ice form. That's how a glacier is made. The cool thing about these glaciers is that they leave imprints in the ground, kind of like fossils. So we can tell what the world was like when it was covered by glaciers hack during the Ice Age.