About 21% of Earth's atmosphere is composed of oxygen. Oxygen can combine with other substances. The chemical reaction
of oxygen with other substances is called oxidation and it is a source of chemical weathering. The building on the left has
undergone oxidation. Compare the picture on the left with the picture on the right. The building has changed. The rock has
changed much like the building.
Formulate how the rock on the right has changed over time.
Chemical weathering has happened due to acid rain in the area.
Oxygen has chemically reacted with minerals in the rock; oxidation has
occurred.
Water in the atmosphere has caused the rock to rust; it has physically
weathered.
Physical weathering has taken place and the rock is broken down into
smaller pieces.