This document summarizes key concepts about weathering and soil formation: 1. It describes different types of weathering including mechanical, chemical, abrasion, root-pry, exfoliation and defines byproducts like sulfuric acid and humus. 2. It outlines the major horizons that make up soil profiles including the O, A, B, and C horizons and defines characteristics like pore spaces. 3. It lists the main ingredients that compose soil as weathered rock and organic material and the four sizes of particles as gravel, sand, silt, and clay. 4. Finally, it identifies four conditions needed for soil horizons to develop: time, climate, types of