Geo Homework Oxidization and Carbonation

Name: Kristen Jackson
Form: 35
Date: May 30, 2012

Geography Homework

1. Explain the difference in the process between carbonation and oxidation.

When carbon dioxide in the air dissolves in rain, a weak carbonic acid is formed. This weak acid, while harmless to plants and animals, is able to dissolve some kinds of rocks, like feldspar and limestone, in a process called carbonation. Many caves begin forming during the process of carbonation. On the other hand, any mineral that reacts with oxygen in the atmosphere will produce an oxide. Therefore, when an object made of iron is left exposed to the atmosphere it will oxidize and rust will form on the surface. Oxidation produces a reddish-brownish colour.

2. Draw & label a diagram to show how plants and animals break down rocks.

Some marine organisms secrete chemicals that can dissolve rock. Plant root growth penetrates small cracks and crevices in rock and spreads them further apart. Other plants can attack the surface of rock directly, extracting nutrients. Just the action of walking and scurrying about causes rocks to rub against other rocks, slowly breaking them apart. 3. Differentiate between frost action and temperature change.

Frost action is a type of weathering where water actually seeps into cracks in the rock. The water freezes as the temperature drops. As water freezes it expands. This expansion creates a wedge inside the rock, encouraging is to crack and split apart.

On the other hand, rocks will crack if their temperature changes quickly. This may occur at night after a hot day or when rain falls on hot rocks. Eventually the outer layers of the rock crack and may peel off. This process is very common in granite and eventually rounded boulders are formed.