Weathering is the process which breaks rocks into smaller bits. An example of this is called freeze-thaw weathering when water gets into tiny cracks in rocks. When the water freezes it expands, if this is repeated the crack grows and bits eventually break off. Biological weathering is when rocks are weakened and broken down by animals and plants. An example would be a tree root system slowly splitting rocks.
Erosion is a type of physical weathering which involves wearing down rocks.
Read about the disaster at Beachy Head . There is an important point to remember. Dartmoor is an upland area of 241 square miles reaching up to 2,000 feet in height making it the largest and highest area of moorland in the South of England. It is also the largest granite surface in England. The rock cycle goes round and round, taking hundreds of millions of years.