This document discusses different types of weathering that break down rocks over time. It defines freeze-thaw heating and cooling, chemical weathering by acid rain, and biological weathering by organisms. Examples are given of each type of weathering and how they affect rocks. Chemical weathering occurs slowly from natural acid rain and more rapidly from human-caused acid rain. Biological weathering happens when organisms like plant roots cause cracks in rocks.

1. Freeze-Thaw Heating & Cooling Explain these terms.

3. 8G Weathering Rock does not last forever. Look at the picture here – how can you tell that the rock has been damaged by the environment? What might have done this damage?

6. What is chemical weathering?

7. Slow and rapid chemical weathering Rainwater is naturally acidic because carbon dioxide in the air reacts with rainwater to form carbonic acid. This type of acid rain is weakly acidic and reacts slowly with minerals in rock. The burning of fossil fuels produces oxides of sulphur and nitrogen which make rainwater more acidic . This type of acid rain reacts quickly with minerals and weather rock more rapidly. Slow chemical weathering Rapid chemical weathering

8. Examples of chemical weathering How has chemical weathering affected these rocks?

9. 8G Break it, move it, shape it! Rocks may last a long time but they do change. Even the toughest rocks can be broken down to smaller particles. We call this process weathering . Small particles may be moved around to new areas. We call this transportation . The two processes together (weathering and transportation) are called erosion .

10. Erosion and weathering… EROSION is when rocks are gradually worn down. WEATHERING is when rocks are broken up into smaller ones. The ultimate result of both of these processes is SOIL.

11. What is biological weathering?

12. Examples of biological weathering How has biological weathering caused these cracks to form?

13. Explain how the rocks are broken down using the diagrams: