... to fall down again. If you threw the rock hard enough, though, you could make it escape the planet's gravity entirely. It would keep on rising forever. The speed with which you need to throw the rock in order that it just barely escapes the planet's gravity is called the "escape velocity." As you would expect, the escape velocity depends on the mass of the planet: if the planet is extremely massive, then its gravity is very strong, and the escape velocity is high. A lighter planet would have a smaller escape velocity. The escape velocity also depends on how far you are from the planet's center: the closer you are, the higher the escape velocity . The Earth's escap ...

... contact with acid rain is affected. Among one of the serious side effects of acid pollution on humans is respiratory problems. The SO2 and NO2 emmisions give rise to respitory problems such as asthma, dry coughs, headaches, eye, nose and throat irritations. An indirect effect of acid rain on humans is that the toxic metals dissolved in the water are absorbed in fruits, vegetables and in the tissues of animals. Even though these toxic metals do not directly affect the animals, they have serious effects on humans when they are being eaten. How did it happen? One of the main causes of acid rain is sulphur dioxide. Natural sources that let out this gas are volcanoe ...

... This communication would not be possible if not for the guanine nucleatides that allow the binding of the enzymes to occur. Not only does epinephrine trigger the chemical reactions by bonding to the guanine nucleotides, but they also trigger the production GDP by reducing GTP to its subserviant level. Not all effectors are triggered by simply hormones. Cells in the retinal area of the eye are triggered by photons that strike rhodopsin. When the rhodospin it activates the G protein, transductin, to travel to the effector enzyme, and thus regulates the levels of soduim ions (Na+). The eye cells become hyperpolarized, thus producing a negative charge, signaling vis ...

... cactus. Other forms of use include teas, smoking, intravenous injection, and in powder form using capsules. It is sold as a street drug and it is for readily available in the south western states and in areas where it is used in ceremony. Mescaline carries a wide margin for dosage error and has little or no withdraw effects, although the dangers do increase with higher dosages. A light dose (100-200mg) can give the user feelings of giddiness or anxiety, and a moderate dose of Mescaline (200-300mg) begins to impair the senses. Strong doses (300-500mg) will induce hallucinations and effect the user's perceptions of color, time, and space. Heavy does of Mescal ...

... as 1.1 million years ago and was on earth at the sametime as homo habilis and homo erectus. Most of the australopithecus fossils that have been discovered have been found in eastern africa and have been dated between 4.5 million and 1.1 million years old. There has also been evidence that the australopithecus "man" lived in australia where fossils have also been found. The first discovery of an australopithecus fossil was made in 1924. The body of the australopithecus is smaller than humans, but biffer than chimpanzees. Also, The brain size of australopithecus is bigger than humans at about 475 cubic centimeters. This is also biffer than the chipanzees, but the ...

... 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 into a crude molten metal. Uses- The gi ...

... to hide from the people following him. After arriving, Jack went to the control room to find that the people running the plant were making a big mistake. He saw the people raising the power back up to 100%. He tried to explain that there could be another accident if they raised the power all the way because of a problem with the pumps. The people didn't believe Jack and were starting to raise the power up again. When Jack saw what they were doing he grabbed the security officer's gun and forced everyone out of the control room. After he locked the door he lowered the power down to 75% so the pumps wouldn't break. Jack agreed to have a one on one interview with ...

... and streams in the western United States are usually not acidic. Because of differences in emissions and wind patterns, levels of acid deposition are generally lower in the western United States than in the eastern United States. This chart shows that not all fish, shellfish, or their food insects can tolerate the same amount of acid: Generally, the young of most species are more sensitive than adults. Frogs may tolerate relatively high levels of acidity, but if they eat insects like the mayfly, they may be affected because part of their food supply may disappear. As lakes and streams become more acidic, the numbers and types of fish and other aquatic plants a ...

... When a baby is born prematurely there are a number of tests that the baby has to go through. First the doctors and nurses have to assess the baby’s heart, lungs, color and temperature. If the baby is having trouble with any of these things then it is taken into what is called the neonatal intensive care unit. In some of the smaller hospitals they aren’t equipped with the technology that is needed to keep the baby alive and the baby has to be transported to a bigger hospital, usually to a hospital in a metropolitan city in order to get the proper care. After the baby has been assessed for problems then it is watched closely for the next 48 hours. This is the mos ...

... expanded and cooled. Several million years later, it condensed into galaxies. The universe has continued to expand, and the galaxies have continued moving away from each other ever since. Today the universe is still expanding, as astronomers have observed. The Steady State model says that the universe does not evolve or change in time. There was no beginning in the past, nor will there be change in the future. This model assumes the perfect cosmological principle. This principle says that the universe is the same everywhere on the large scale, at all times.2 It maintains the same average density of matter forever. There are observational evidences f ...