There are two main types of weathering: chemical and freeze-thaw weathering. Chemical weathering occurs when rainwater dissolves limestone through a chemical reaction. Freeze-thaw weathering happens when water collects in cracks and freezes, expanding to widen the cracks and eventually cause rock blocks to break off. Repeated freeze-thaw cycles can form landforms like tors from the weathered scree.

1. Weathering by David Edwards

2. There are two main types of weathering which are called: Chemical Weathering & Freeze-Thaw Weathering

3. Chemical Weathering

4. Chemical weathering is when rain water (carbonic acid) reacts with limestone and dissolves or removes the limestone slowly.

5. The rain water flows down the joints and into the bedding planes, and over time the joints widen to create grykes.

6. This happens because the rock is PERVIOUS

7. Pervious rock allows water to flow through the joints and bedding planes, but not sink through the rock itself.

8. The equation for chemical weathering is: Limes tone + Carbonic Acid (rain water) = Calcium Bicarbonate (soluble lim estone) Or CaCO ³ + H ² CO ³ = Ca(HCO ³ ) ²

9. Freeze-thaw Weathering

10. Water collects in the cracks and joints in the rock . This is how freeze-thaw weathering works:

11. The temperature cools and the water freezes, expanding by 9% in the cracks., and the increased pressure leads to cracks widening.

12. Repeated freeze-thaw action increases the size of the crack until a block of the rock breaks off. These loose bits of rock are called scree.

13. Freeze-thaw weathering can lead to the forming of tors such as "Bowermans' Nose".