The process by which rocks are broken down into smaller fragments is called weathering. Through the contact with the atmosphere of the earth and other factors in the environment like biota and waters, rocks, soil, and minerals are broken down. Weathering is classified into 2 important processes--- physical and chemical process. When the breaking down of the rocks or soil is due to the direct contact with the condition of the atmosphere like heat, ice, water, and pressure, it is classified as mechanical or physical weathering process. It is only considered chemical process when it involves with the direct effect of the atmospheric chemicals.