PHYSICAL WEATHERING Physical weathering takes place when rock is split or broken into smaller pieces.
FREEZE THAW Water seeps into small cracks in a rock. When the water freezes, it expands, causing the rock to break apart. This happens where winters are very cold and temperatures are often below zero.
ONION - SKIN WEATHERING This happens when there is a marked change in the daily temperature. During the day, it is very hot and the outside of the rocks heat up and expands. The same rock cools at night, when the temperatures go drastically down, causing the rock to contract. The process repeats itself day after day, causing the rock to break off in slabs .
PICTURES SHOWING HOW THE TOP LAYERS OF THESE ROCKS ARE BREAKING AWAY.
CHEMICAL WEATHERING <ul><li>ROCKS ARE WEATHERED BY THE EFFECT OF RAIN MIXED UP WITH DIFFERENT ACIDS. </li></ul><ul><li>SOME ROCKS TURN INTO CLAY WHEN MIXED WITH WATER. </li></ul><ul><li>ROCKS WITH A HIGH PERCENTAGE OF IRON ARE AFFECTED BY RUST WHEN DAMP OR WET. </li></ul>
STATUES IN HIGHLY POLLUTED CITIES GET WORN AWAY BY THE EFFECTS OF ACID RAIN ON THEM. Can you think of another type of weathering affecting this statue?
WHY WOULD YOU SAY THIS ROCK HAS A HIGH PERCENTAGE OF IRON IN IT?
GRAVESTONE AFFECTED BY BOTH OXIDATION AND ACID RAIN
OXIDATION Rust appears on the outside of these rocks. Nevada’s Valley of Fire
STALACTITES AND STALAGMITES Limestone is dissolved to form these stalactites,stalagmites and caves.
SOME ARE MORE RESISTANT THAN OTHERS SO THEY ARE NOT WEATHERED AWAY SO EASILY. ROCKS ARE AFFECTED IN DIFFERENT WAYS BY WEATHERING.
BIOLOGICAL WEATHERING Plants and animals can also cause weathering. Seeds can find their way into the cracks in rocks where they can sprout and grow. As the plant grows its roots grow down into the crack in the rock and eventually get larger. The growth of the plant can cause the rock to break apart.