Welcome to Science 11/21/11 Open your book to page 255 and get your notes out for Ch. 10. Today’s Schedule 1. Review Sections 1 & 2 2. Question of the Day 3. Note/Discussion Ch. 10 Section 3 4. Work on Weathering and Soil Formation Packets

Question of the Day What is the world’s most important natural resource? soil

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

Where does soil come from? Bedrock- one of the main ingredients of soil. Solid layer of rock beneath the soil.

What is soil made of? Soil is a mixture or rock particles, minerals, decayed organic material, water, and air.

What is soil made of? Humus- dark colored substance that forms as plant and animal remains decay.

HUMUS + + = Weathering Which is really good soil !!!!!!!!!

When you have really good soil it is fertile. Fertility- a measure of how well the soil supports plant growth

Soil Texture Loam- soil that is made up of equal parts of clay sand, and silt.

How is soil made? Soil forms as rock is broken down by weathering and mixes with other materials on the surface. Soil is constantly being formed wherever bedrock is exposed.

How is soil made? Soil Horizon- A layer of soil that differs in color and texture from the layer above or below it.

How is soil made? Topsoil- The A horizon. Crumbly, dark brown soil that is a mixture of humus, clay, and other minerals.

How is soil made? Subsoil- The B horizon. Clay and other particles washed down from the A horizon.

How is soil made? C Horizon- forms as bedrock weathers and rock breaks up into soil particles.

Soil Types Scientists classify the different types of soil into major groups based on climate, plants, and soil consumption.

Where does humus come from? Living Organisms in Soil Litter- loose layer of leaves, twigs, and other dead plant matter

Where does humus come from? Decomposers- organisms that break down the remains of dead organisms into smaller pieces