B Methane Gas

Methane The methane molecule is the simplest example of how a carbon atom can bond to fourother atoms to form a tetrahedral shape. The carbon atom sits at the center, with the four hydrogen atoms at the points of the tetrahedron. Carbon’s ability to form four strong bonds is unique among the elements and allows it to form large molecules.

Greenhouse Effect, the capacity of certain gases in the atmosphere to trap heat emitted from the Earth’s surface, thereby insulating and warming the Earth. Without the thermal blanketing of the natural greenhouse effect, the Earth’s climate would be about 33 Celsius degrees (about 59 Fahrenheit degrees) cooler—too cold for most living organisms to survive. Sidebar SCIENTIFIC DISCOVERIES Scientific Group Issues Climate Change Warning The American Geophysical Union, a leading scientific organization, issued a warning in January 1999 that global warming trends are cause for concern and may be at least partially attributable to human activity. An Encarta Yearbook article reported

The greenhouse effect results from the interaction between sunlight and the layer of greenhouse gases in the Earth's atmosphere that extends up to 100 km (60 mi) above Earth's surface. Sunlight is composed of a range of radiant energies known as the solar spectrum, which includes visible light, infrared light, gamma rays, X rays, and ultraviolet light. When the Sun’s radiation reaches the Earth’s atmosphere, some 25 percent of the energy is reflected back into space by clouds and other atmospheric particles. About 20 percent is absorbed in the atmosphere.

Presentation By: SANDEEP GHAI DAVINDER SINGH MANDEEP SINGH MANJINDER SINGH. CLASS:-9th

Bibliography Class 9th Test Book. MS Encyclopedia (Encarta)