. . . "Digital video"@en . . . . . . . . . . . . . . . . . "Examines the chemistry of the earth's atmosphere. Explains theories of chemical evolution, ozone depletion, and the greenhouse effect."@en . "\"The earth's atmosphere is examined through theories of chemical evolution; ozone depletion and the greenhouse effect are explained.\"--Container."@en . . "The precious envelope" . "The precious envelope"@en . "Introduces this exploration of the chemistry of our planet's atmosphere: what it is made of, how it was formed, and how it is being threatened today."@en . . . "Chemistry of earth" . "Chemistry of earth"@en . . . . . . . . "Chemistry of the earth"@en . "Chemistry of the earth" . . . "Program 17 examines the chemistry of the earth's atmosphere. Theories of chemical evolution, ozone depletion, and the greenhouse effect are explained. Program 18 explains where minerals come from and why some are common and some are rare."@en . "The chemistry of earth's atmosphere is examined. Theories of chemical evolution, ozone depletion, and the greenhouse effect are explained."@en . "Streaming multimedia"@en . . "Explores the chemistry of Earth's atmosphere, how it may have formed and how human activities affect its future."@en . . . . . . . . . . . "Video recordings for the hearing impaired"@en . . . "Examines the chemistry of the earth's atmosphere; explains theories of chemical evolution, ozone depletion, and the greenhouse effect." . . . . . "\"Explores the chemistry of our planet's atmosphere - how it may have formed and how human activities affect its future. Highlights: atmospheric composition, ozone layer, primitive atmosphere, geologic cycles, and the Greenhouse Effect.\"--Magic Lantern Web site."@en . . . . . . "This program explores the chemistry of our planet's atmosphere -- how it may have formed and how human activities affect its future."@en . . "Video"@en . . . "In the 1st program the chemistry of earth's atmosphere is examined. Theories of chemical evolution, ozone depletion, and the greenhouse effect are explained. The 2nd program explains where minerals come from and why some elements are common and some rare. Also investigates the abundance of elements and their uses in modern society."@en . "In the 1st program the chemistry of earth's atmosphere is examined. Theories of chemical evolution, ozone depletion, and the greenhouse effect are explained. The 2nd program explains where minerals come from and why some elements are common and some rare. Also investigates the abundance of elements and their uses in modern society." . . . . . . "The Precious envelope"@en . . "The Precious envelope" . . . . . . "Greenhouse effect, Atmospheric." . . . . "Annenberg/CPB Project." . . "Atmospheric chemistry." . . "Annenberg/CPB Collection." . . "Ozone Environmental aspects." . . "University of Maryland (College Park, Md.)" . . "University of Maryland, College Park." . . "Alberta. Alberta Learning. Learning Resources Centre." . .