Weathering and Erosion Chapter 14 Answers to Questions 1-6, & 8 page 348

Three Agents of Mechanical Weathering Three agents of mechanical weathering are wind, water, and temperature

How Does Ice Wedging Weather Rocks? Water seeps into cracks and then freezes and expands, which widens and deepens cracks with each freeze and thaw cycle.

2 Activities of Plants or Animals that Help Weather Rocks or Soil Plants: their roots grow and expand, physically wedging rocks apart. Animals: dig & burrow, which exposes new rock to the weathering process.

Mechanical vs. Chemical Weathering Mechanical: Rock is split or broken into smaller material without changing its composition. (Physical process) Chemical: Break down of rocks when the rock minerals are changed to different substances. (Chemical reactions take place)

3 Chemical Processes that Weather Rocks Hydrolysis - chemical reaction with water and other substances (feldspar, hornblende, augite) these combine to form clay. Oxidation - chemical reaction with oxygen and other substances. (Iron bearing substances) , (red soil in Carolina & Virginia) Carbonation - Carbon dioxide dissolves in H2O to form carbonic acid. Speeds up the process of hydrolysis. Converts compounds into a carbonate.

Compare Hydrolysis, Carbonation, and Oxidation Oxidation, hydrolysis and carbonation are all chemical processes that weather rocks. Water plays a role in both hydrolysis and carbonation and it can speed up oxidation. Oxidation involves elements combining with oxygen. Hydrolysis changes the composition of minerals that react with water. Carbonation occurs when minerals react with carbonic acid.

2 Agents of Weathering that Would be Rare in the Desert Running water and vegetation Rainfall is low in the desert areas, so fewer streams & rivers exist to erode valley areas. Low precipitation also limits plant growth, so fewer plants means fewer roots to break up the soil & less shelter for animals, which in greater numbers also expose soil to weathering.

Frost Wedging

Chemical Weathering