Please fill out and return this sheet after viewing Program #7.   If you are unsure of an answer, give your best intelligent guess.

1.  What is weathering?

The disintigration of rock by surface processes.

2.  What are the two types of weathering?

Mechanical and chemical weathering

3.  What is pressure release?  What is frost wedging?

Pressure release is fracturing that results from the erosion of enormous amounts of overlying rock.  The buried rock expands and fractures.  Frost wedging is the growth of rock fractures by the repeated freezing and thawing of water in the fractures.  Freezing causes expansion of the ice over the water, and the crack opens a little wider.

4.  How is a rock's composition affected by mechanical weathering?

A rock's composition is not changed by mechanical weathering.  Only the size of the fragments decreases.

5.  How does mechanical weathering aid chemical weathering?

Mechanical weathering breaks rocks down into smaller fragments, and increases the surface area of the over all material.  By increasing the surface area, chemical processes may act more easily upon the rock surface.

6.  What are some products of chemical weathering?

Some products are clay minerals, and iron oxide (hematite)

7.  What type of climate favors weathering?

Warm, moist climates favor weathering.

8.  Why aren't deserts a great weathering environment ?

Because they are dry, and weathering is not as effective without water.

9.  How does Bowen's Reaction Series give information about which minerals weather more easily?

Minerals at the top of Bowen's Reaction Series (example, olivine) weather more easily than do minerals at the bottom of Bowen's reaction series (example, quartz).

10.  How has humanity sped up the process of weathering?

Pollutants like SO2 increase the acidity of rain (acid rain) which aids in the effectiveness of weathering.

11.  What is the main culprit in the formation of acid rain?

sulfer dioxide

12.  What role does weathering play in the development of soil?

Weathering breaks the rock down so that it is available to plants and organic debris for the productin of soil.

13.  Why is the mineral apatite so important to soils?

It is the source of the nutrient, phosphate that is important to plants and animals.

14.  Which soil horizon is richest in humus?  Which soil horizon looks most like bedrock?

A horizon; C horizon

15.  What minerals do feldspars and some other silicate minerals change to as a result of chemical weathering?

clay minerals

16.  Which rock weathers quickest?  granite or basalt?

basalt, because it's minerals are more unstable to surface weathering processes than granite.

17. How long can it take for soil to form?

one to fifteen thousand years, depending on the climate and conditions

18.  What are some techniques of soil conservation?

wind breaks, crop rotations, tilling/plowing techniques, watering techniques