Natural processes, including freezing and thawing and the growth of roots, cause rocks to break down into smaller pieces.
The California Science Framework (page 64) distinguishes between chemical weathering and physical weathering. In both cases, the term weathering is used in its technical sense in geology meaning the breaking of rocks to smaller pieces. Rainwater and groundwater are generally somewhat acidic due … Continue reading the story "Natural processes, including freezing and thawing"
Post Archives tagged ‘rocks’
The properties of rocks and minerals reflect the processes that formed them
Waves, wind, water, and ice shape and reshape Earth's land surface.
Rocks on the Earth’s surface are continually broken down by chemical and physical processes. Rainwater is slightly acidic because it contains dissolved carbon dioxide from the air. This weak acidity can chemically cause rocks to break apart and dissolve. Physical processes such as grinding by glaciers, pounding by waves, the freezing/thawing … Continue reading the story "The properties of rocks and minerals reflect the processes that formed them"
Students know how to differentiate among igneous, sedimentary, and metamorphic rocks by referring to their properties and methods of formation (the rock cycle).
Since rocks are made of minerals, the California Science Framework recommends teaching about minerals (Standard 4b) before rocks (Standard 4a). The order of content in the standards does not imply any sequence in teaching the standards.
The terms igneous, metamorphic, and sedimentary indicate the processes that formed the particular rocks. Since any given rock can be made from a wide … Continue reading the story "Students know how to differentiate among igneous, sedimentary, and metamorphic rocks by referring to their properties and methods of formation (the rock cycle)."