Weathering and Soil Formation

Question 1

The process that breaks down rock and other substances at Earth’s surface.

Answer 1

Weathering

Question 2

The removal of rock particles by wind, water, ice, or gravity.

Answer 2

Erosion

Question 3

What are the two types of weathering?

Answer 3

Mechanical and Chemical

Question 4

What type of weathering causes rocks to be physically broken into smaller pieces.

Answer 4

Mechanical Weathering

Question 5

Name 2 causes of mechanical weathering.

Answer 5

Freezing and Thawing

Release of Pressure

Plant Growth

Actions of Animals

Abrasion

Question 6

What is abrasion?

Answer 6

The term abrasion refers to grinding away of rock by rock particles carried by water, ice, wind, or gravity.

Question 7

The process that breaks down rock through chemical changes.

Answer 7

Chemical Weathering

Question 8

Name two causes of chemical weathering.

Answer 8

Action of Water

Oxygen

Carbon Dioxide

Living Organisms

Acid Rain

Question 9

What is the most important cause of chemical weathering?

This type of chemical weathering causes rocks to dissolve.

Answer 9

Water

Question 10

The oxygen gas in the air is an important cause of chemical weathering in rocks that contain iron. What is the process called when Iron combines with Oxygen?

Answer 10

Oxidation

Oxidation creates rust and rust makes rock soft and crumbly and gives it a red or brown color.

Question 11

What type of rock weathers more easily?

Answer 11

Permeable

Permiable means that the material is full of tiny, connected air spaces that allow water to seep through it.

Question 12

What is the loose, weathered material on Earth’s surface in which plants can grow?

Answer 12

Soil

Question 13

One of the main ingrediants of soil comes from __________.

___________ is the solid layer of rock beneath the soil.

Answer 13

Bedrock

Once bedrock is exposed at the surface, it gradually weathers into smaller and smaller particles that are the basic material of soil.

Question 14

What is the composition of soil?

Answer 14

Soil is more than just particles of weathered bedrock. Soil is composed of a mixture of rock particles, minerals, decayed organic material, water and air.

Question 15

What is the dark-colored substance that forms as plant and animal remains decay?

Answer 15

Humus

Humus helps create spaces in soil for air and water that plants must have. It also contain nutrients for the plants growing in the soil.

Question 16

What does fertility tell us about the soil?

Answer 16

Fertile soil is rich in the nutrients that plants need to grow and be healthy. The fertility of the soil is a measure of how well the soil supports plant growth.

Question 17

Soil that is made up of about equal parts of clay, sand, and silt is called?

Answer 17

Loam

Loam has a crumbly texture that holds both air and water.

Question 18

Gradually, soil develops layers called?

Answer 18

Horizons

A soil horizon is a layer of soil that differs in color and texture from the layers above and below it.

Question 19

The A horizon is made up of what type of soil?

Answer 19

Topsoil

Topsoil is a crumbly, dark brown soil that is a mixture of humus, clay, and other materials.

Question 20

The B horizon is called?

Answer 20

Subsoil

Subsoil usually contains clay and other particles washed down from the A horizon, but little humus.