The hole glacier moves along by melting and freezing again a little at a time. Some glaciers move as much as 60 to 70 feet a day. A moving glacier picks up and carries with it all the loose materials in its path. Stones held by the ice leave scratches in solid rock. The scratches show that a glacier moved over the land and also the direction in which it moved.
Rain plays a very important part in molding the face of the earth.
Its action is partly chemical and partly physical. In considering the chemical action of rain, you must keep in mind that it is not pure water. In the atmosphere it absorbs atmospheric gases oxygen, nitrogen, carbon dioxide. It also absorbs a certain amount of nitric acid, sulfuric acid and salts. Rain, than, has a varied chemical action on the rocks and soil on which it falls.