.... when the sun is directly over the equator and it complies with the first day of spring. It also means that the sun is an equal distance from the north and south poles. At this time both hemispheres have the same amount of sun as the sun makes its way north. Before the vernal equinox the sun hits the northern surface at an angle instead of hitting it directly. By hitting the earth's surface at an angle there is not as much radiation warming the surface. As the earth rotates and the sun moves further north the temperature increases and the weather turns warmer. During the three months of spring the sun continues to move north and warming the earth more efficiently. ....

.... mission, piloted by John W. Young and Robert Crippen aboard the orbiter Columbia, was launched on April 12, 1981. It was a test flight flown without payload in the orbiter's cargo bay. The fifth space shuttle flight was the first operational mission; the astronauts in the Columbia deployed two commercial communications satellites from November 11 to 16, 1982. Later memorable flights included the seventh, whose crew included the first U.S. woman astronaut, Sally K. Ride; the ninth mission, November 28-December 8, 1983, which carried the first of the European Space Agency's Spacelabs; the 11th mission, April 7-13, 1984, during which a satellite was retrieved, repaired, a ....

.... center no longer has an opposing force to act against it. As a result the star collapses. A star that once had eight times as much matter as our sun and was 1,000,000 miles across, becomes a sphere only ten to fifteen miles across. As the star collapses, very small particles (called neutrinos) escape into space. After the star becomes a very small sphere, it explodes like a giant nuclear bomb and becomes a billion times as bright as our own sun. All kinds of matter and radiation are blasted into space. This matter and radiation travels through space at nearly the speed of light (186,000 miles per second) Now, if one of these supernovae were to occur within about ....

.... of aluminum and show it'd lightness. In 1854, Henri Sainte-Claire Deville obtained the metal by reducing aluminum chloride, with sodium. Deville displayed pure aluminum at the Paris exposition of 1855. Aluminum the most abundant metallic constituent in the crust of the Earth. It is never found as a non-metal. It occurs most commonly as aluminum silicate or as a silicate of aluminum mixed with other metals such as sodium, potassium, iron, calcium, and magnesium. Charles M. Hall and Paul L. T. Heroult, independently and almost simultaneously found out that alumna, or aluminum oxide, would dissolve in fused cryolite (Na3AlF6) and then could be decomposed electronically in ....

.... effects of each pesticide. The Agency imposes any regulatory controls that are needed to effectively manage each pesticide's risks. EPA then reregisters pesticides that can be used without posing unreasonable risks to human health or the environment. When a pesticide is eligible for reregistration, EPA announces this and explains why in a Reregistration Eligibility Decision (RED) document. This fact sheet summarizes the information in the RED document for reregistration case 3083, limonene. Use Profile Limonene is a naturally occurring chemical which is used in many food products, soaps and perfumes for its lemon-like flavor and odor. Limonene also ....

.... Tropp, 1995). Desertification is the land degradation of productive drylands in arid, semiarid, and dry subhumid areas as a result of various factors, including climatic variations and human activities (World Atlas of Desertification, 1997) These drylands have been central in the evolution of mankind. These are the lands that sustained our transition from a hunting/gathering to pastoralism and agriculture (Kaya and Yokobiri, 1997). Drylands still provide much of our grain and livestock. These areas cover more than 40 percent of the world’s land surface. As these areas decrease in size, so does the reliability of the land to support the human population. In some area ....

.... These sharks are easy to recongnize due to the fact that they posses an ellongated blade like snout that is lined with sharp teeth along the edges, thus, the name saw sharks. SQUALIFORMES: The order possesses three family which consist of about 82 species. These sharks are characterized by their slender, cylinder-shaped bodies, long snouts with shortened mouths. HEXANCHIFORMES: The Hexanchiformes or cow sharks, comprise of two families. Recognized by their six or seven pairs of gill slits, there sharks can often be found in deep water. The frilled shark (CHLAMYDISELACHUS ANGUINEUS) who's appearance is quite unmistakable due to it's "eel" like appearance, is perha ....

.... while swimming. The body is plump, the back arched, the neck thick, the hind feet webbed, and all the digits clawed. The fur is usually reddish-brown above and lighter or grayish below. The eyes are small and the nostrils closable. The skull is massive, with marked ridges for fixing the muscles that work the jaws. The two front teeth on either jaw are like those of other rodents, wearing away more rapidly behind so as to leave a sharp, enameled chisel edge. With these can cut down large trees. It usually selects trees 5 to 20 cm (2 to 8 in) in diameter, but it can fell trees with diameters as large as 76 cm (30 in). Beavers have a pair of anal scent glands, called casto ....