High School Earth, Space, and Geophysical Curriculum Essentials May 2009 10. Boulder Valley School District High School Earth, Space, and Geophysical. Science Curriculum Essentials Document. If learning is to endure in a flexible, adaptable way for future use, then teachers must design units.
A curmudgeon with years of practice. Coal ash is the residue from burning coal and contains all of the nonvolatile components of he coal (carbon compounds, sulfur and some metals). The ash is made up of silicates, metals (including toxic metals like mercury and uranium) and some unburnt carbon.
The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure. Coal is composed primarily of carbon along with variable quantities of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Lignite, or brown coal, is the lowest rank of coal and used almost exclusively as fuel for electric power generation. 2  Jet, a compact form of lignite, is sometimes polished and has been used as an ornamental stone since the Upper Palaeolithic.