Chapter 2 Lesson 1 – Weathering

Weathering physical and chemical processes that change objects on Earth’s surface over time, causing them to break down Examples – paint fading, metal turning rusty, wood drying out, rocks turning smooth How long does it take? Long time Breaks, wears, abrade, or chemically change Sediments – rock that has been broken into small pieces through weathering

Mechanical weathering – physical processes naturally breaking down rock Ice (frost) wedging ice expanding inside of rock to force it apart Abrasion grinding away of rock by friction or impact Plants/Animals Surface area how much surface something has

Chemical weathering – change in rock into a new material Examples Water – important because water can dissolve material Acids – breaks down materials faster than water Oxidation – combines oxygen with other elements or molecules (RUSTING)

Rate of weathering The environment – water, temperature, wind The rock – material, size Environment – physical, chemical, and biological factors acting in a community

Chapter 2 Lesson 2 - Soil

What is soil? a mixture of weathered rock, sediment, decayed organic matter, water, and air Organic matter the remains of something that was once alive Pores small holes and spaces in soil provides space for water and air to move Decomposition the process of changing once-living material into dark-colored organic matter Inorganic materials that have never been alive Sand, silt, and clay

What is parent material? starting material of soil (source of soil) – where the soil comes from Topography the shape of land Biota all living things in a region

Soil takes a long time to form – thousands of years Horizons layers of soil formed from the movement of sediments A-horizon - dirt (lots of organic matter) B-horizon - clay C-horizon – parent material Soil properties Color, texture, structure, consistency, infiltration, soil moisture, pH, fertility, temp