HOW DO GLACIERS FORM VALLEYS?
We read about valleys that were shaped/formed by glaciers. Since glaciers are just ice, and ice is just water, how can it be that glaciers can cause the formation of alleys? Frequently, the text will inform us that the glaciers “grind” the walls of the valley. Let’s find out how that can be. Rub an ice cube across the painted surface of a board. Note that the ice is not hard enough to abrade the surface. Now press the ice cube into a dish of sand. When the ice has melted a bit, place the dish, with the ice cube still in it, in the freezer. After the ice cube has refrozen, remove the cube from the dish, and rub it across the board again. Looks like it made a few scratches, doesn’t it? By freezing some grains of sand into the ice cube, we caused it to have an abrasive surface. The constant melting and re-freezing of glaciers is only a small part of what causes them to move along the surface of the land. Gravity, coupled with their tremendous weight, is mainly what causes them to move. Wh
