1. Mechanical and chemical forces break down rock
When you are walking in your neighborhood how do you think the small rocks are formed?

2. Mechanical and chemical forces break down rock
Weathering, which is the process by which natural forces break down rock.

3. Mechanical and chemical forces break down rock
There are two ways in which weathering can occur.
Physically broken apart and chemically

4. Mechanical and chemical forces break down rock
Mechanical weathering breaks up rock by physical forces.
Those physical forces split apart rock
Mechanical weathering can be caused by ice wedging, pressure release, plant root growth, and abrasion.

5. Mechanical and chemical forces break down rock
Ice wedging causes mechanical weathering. When water freezes in the cracks and pores of rocks, the force of its expansion is strong enough to split apart rock.

6. Mechanical and chemical forces break down rock
Pressure release is the next method. Rock deep within the earth’s surface is under great amounts of pressure. Over time the rock is pushed up to the surface of the earth.

7. Mechanical and chemical forces break down rock
When the rock reaches the surface the pressure is released and the rock expands. As the rock expands cracks from in it causing weathering.

8. Mechanical and chemical forces break down rock
Plant Root growth is method in mechanical weathering. When plants grow in a rock, their roots can widen the crack and force the rock apart. Thus mechanical weathering takes place.

9. Mechanical and chemical forces break down rock
Abrasion is the final method in mechanical weathering. Water alone can wear down rocks, but they also can move rocks downstream causing them to rub together and wear down into rounded shapes.

10. Mechanical and chemical forces break down rock
When elements react with water and air they can cause the breakdown of rocks. This is of course chemical weathering.

11. Mechanical and chemical forces break down rock
When minerals in rocks come into contact with air and water, some dissolve and others react and are changed into different minerals.

12. Mechanical and chemical forces break down rock
Water is the main cause of chemical weathering.
Water and carbon dioxide mix with decaying plants and breaks down rock into smaller pieces.

13. Mechanical and chemical forces break down rock
Oxygen is also a major factor in chemical weathering.
When minerals dissolve in water, oxygen in the air and water combines with iron to produce iron oxides or rust.

14. Mechanical and chemical forces break down rock
Just like the rock cycle weathering can take hundreds, thousands, or millions of years.
The surface of the earth will weather at a faster rate because of the exposure to air and water.

15. Mechanical and chemical forces break down rock
Different rocks break down at different rates such as limestone and granite.
Climate can also affect chemical weathering.
Weathering occurs faster in hot wet regions than cold dry regions. Why?

16. Mechanical and chemical forces break down rock
Although mechanical weathering can occur more in cold regions rather than hot. Why?