Glaciers form in two basic areas, the north and south pole. They also tend to start in mountains where it is much colder and they get more snow. Although glaciers are usually in cold regions, there have been glaciers found around Africa. It's most likly like this because of plate techtonics and how Pangea used to be.
Glaciers are made from snow that has been there for thousands of years that has compacted into ice and then forms into a glacier. Each glacier starts out as a single snow flake that has attached to others until it's so heavy it turns to ice. They aren't like ice cubes that can melt and be frozen again. Glaciers are built over several hundred years. After a while, the snow becomes airtight, and then it freezes.
Glaciers move when they get too heavy to stay in one place. When a glacier moves it carves through mountains and valleys. After they pass through a valley they goes from a "v" shape to more of a "u" shape. When a glacier has left an area, it leaves sediments behind, and different land formations. It's almost like they are solid blocks of ice moving down hill, or as if it was a river made of pure ice. Many times after a glacier has passed it leaves a water collection at the bottom off the valley.
Although we are still in an ice age, global warming is comming our way to melt the ice that covers part of our world. When a glacier melts it increases the sea level. During the last ice age ice sheets extended from the polar regions to the mid-latitudes in the northern hemisphere and extending well beyond Antarctica in the southern hemisphere. It is possible that midlatittude ice sheets may return over the next 10,000 years.
Glaciers are the biggest collection of fresh water on Earth. They come to a close second with oceans. Right now the worlds largest glacier is a continent; it is Antarctica.
