Craig Nims, age 7, of Des Moines, Iowa, for has question:

What causes glaciers?

Glaciers are made of winter snows that freeze into hard layers of ice. It takes a lot of cold weather to make them. Experts think that the ones we still have were made during the ice ages. In those days they were very much bigger. But when the world wide weather warmed up, their edges melted and the mighty glaciers began to shrink. Most of those w? have left are in polar regions, where the winters are the longest and coldest.

The ice age glaciers be, An to grow when heavy winter snows fell on the ground. They froze into hard, solid ice    waiting for warmer spring weather to melt them away. But the spring was too cool and the summer too short. Some of the frozen ice was still there when winter r.^ _turL~cd. The next spring left more of it unmelted. The sheets of solid ice became year 'round glaciers. As long, as the summers were too cool to melt the winter snows, the glaciers grew deeper and wider.