What is physical weathering?

Physical weathering is the disintegration of rock by mechanical processes and therefore depends on the application of force. The applied forces could be: 

• Gravitational forces such as overburden pressure, load and shearing stress; 
• Expansion forces due to temperature changes, crystal growth or animal activity; 
• Water pressures controlled by wetting and drying cycles.

Further Reading:

• Physical Weathering
• Weathering