.... In the 20th century, most scientists used oxygen as the standard gas to compare other gases' weights. It is relativly easy to measure the weights of liquids and sloids, the same procedure for gas is followed, more or less. In the early 1960s, though, the international union of chemistry and physics agreed that there would be a new standard, carbon isotope (carbon-12). British physicist Ernest Rutherford found and proved that an atom's mass is concentrated in its its nucleus, which is the center of the atom. He also gave the idea that parts of an atom, called its electrons, orb .....

.... 419 chemicals, this plant has the ability to intoxicate its users, primarily because of the psychoactive mind altering ingredients called Delta - 9 - Tetrahydrocannabinol, or THC. It is the THC content found at various concentration in different parts of the plant, which determines the potency. The THC content is controlled by plant strain, climate, soil conditions, and harvesting, in 1975, the average confiscated sample of marijuana contained 0.4 percent of THC, in 1979 the content was about 4 percent and in the 80's about 7 percent, "today the THC content goes up to a .....

.... But where lies the “point of no return” at which any matter or energy is doomed to disappear from the visible universe? The black hole's surface is known as the event horizon. Behind this horizon, the inward pull of gravity is overwhelming and no information about the black hole's interior can escape to the outer universe. Applying the Einstein Field Equations to collapsing stars, Kurt Schwarzschild discovered the critical radius for a given mass at which matter would collapse into an infinitely dense state known as a singularity. At the center of the black hole lies t .....

.... of gravity through the soil. If soils are dry, water is absorbed by the soil until it is thoroughly wetted. Then excess infiltration begins to move slowly downward to the water table. Once it reaches the water table, it is called ground water. Ground water continues to move downward and laterally through the subsurface. Eventually it discharges through hillside springs or seeps into streams, lakes, and the ocean where it is again evaporated to perpetuate the cycle. GROUND WATER AND SUBSURFACE WATER Most rock or soil near the earth's surface is composed of solids and voids. Th .....

.... 300,00 of its inhabitants died from some sickness. Some people now believe that this great plague was really Ebola. The first recorded outbreak of the Zaire string of the Ebola virus was in Zaire, in 1976. The doctors didn't know how to treat it and that meant that they didn't know how to contain it either. As infected people met in public places the virus spread. In Western Sudan, the same year, the Sudan string of the Ebola virus emerged with similar results. Both casts together had about a total of 550 infections and around 340 deaths (about 60% death rate). Th .....

.... Three separate teams of American scientists operated the first semiconductor laser in 1962. Then in 1966, the American physicist Peter Sorokin built the first dye laser. To begin with, I will explain the definition of a laser: It is a device that produces a very narrow powerful beam of light. A laser light is a narrow beam of light, in which all the waves are traveling exactly at the same length and moving together as one. A laser light is made up of only one wavelength and it is a single pure color, while a normal light has many different wavelengths or colors. The most co .....

.... realized that they could not even make it to Winnipeg. Their only chance was an abandoned to a abandoned Air Force airstrip. Unfortunately, the airstrip had been converted to a race track, complete with race cars, fences, and spectators. The 767 crash landed, and, fortunately, no one was killed. Their were many contributing factors that made this plane run out of fuel. First of all, the computerized fuel gauge was not working, and a maintenance worker said , incorrectly, that the plane was still certified to fly. To measure the amount of fuel remaining, they use a dr .....

.... What happens then in the case of a natural magnet the unpaired electrons line up or the magnet in a specific mannor. That is all the atoms with unpaired electrons moving in a direction which causes a certain charge are lined up on one side and all the atoms with the opposite charge move to the other side. The atoms then start to cancel each other out as they approach the center of the magnet. This all happens at the currie point where these atoms are free to move and then when cooled and the metel becomes solid the atoms can no longer move (barely) causing a "permanent" ma .....