2. What Is Weathering? Weathering is the process that breaks down rocks into smaller and smaller pieces Weathering wears down mountains and breaks down statues

3. What Is Weathering? There are two types of weathering: mechanical and chemical weathering

4. What Is Mechanical Weathering? It breaks apart rocks without changing them chemically There are 5 types

5. What Is Mechanical Weathering? Rocks formed under pressure expand and contract when pressure is released

6. What Is Mechanical Weathering? Ice Wedging occurs when water seeps into cracks in rock & freezes…the rock expands and finally breaks This type of weathering causes potholes in the road

7. What Is Mechanical Weathering? Abrasion is the collision of rocks with one another & agents such as gravity, water & wind

8. What Is Mechanical Weathering? Organic Activity known as root pry As roots of plants can work their way into cracks of rock and break them apart

9. What is Mechanical Weathering? Temperature changes from hot to cold may aid in weathering Rocks expand in hot weather and contract in cold

10. What Is Chemical Weathering? It breaks apart the rock when substances chemically react with the minerals in the rock, changing it into a different substance. There are 4 types of chemical weathering

11. What Is Chemical Weathering? Hydrolysis –minerals change into new compounds when exposed to water

12. Oxidation –Oxygen combines with minerals What Is Chemical Weathering?

13. Carbonation –change in minerals when they react with carbonic acid…CO2 + water –Dissolves limestone forming caves

14. What Is Chemical Weathering? Decaying Plants –Produce acids that break down rocks –Especially mosses and lichens

15. What Affects the Rate of Weathering? Rock Composition: igneous and metamorphic rock weather more slowly Amount of Exposure: the longer a rock is exposed the faster it will weather

16. What Affects the Rate of Weathering? Climate: variable weather conditions accelerate weathering processes Topography: on steep slopes, rocks are weathered more quickly