The Rock Cycle
The Earth’s rocks do not stay the same forever.
They are always changing. Rocks are constantly being formed, changing type and wearing away in a continuous cycle. Rocks are eroded by the weather and worn away by running water, ice, wind, waves, plants and people. Mountains and hills are gradually broken down or eroded into tiny grains. These grains are washed into the sea, compacted together, heated or compressed deep underground and turned back into rock again. The rocks are being gradually recycled over millions of years.