.... it has none; this is because an ideal gas is said to be a particle and particles do not have any mass. Ideal gases obtain no volume unlike real gases which obtain small volumes. Also, since ideal gas particles excerpt no attractive forces, their collisions are elastic. Real gases excerpt small attractive forces. The pressure of an ideal gas is much greater than that of a real gas since its particles lack the attractive forces which hold the particles back when they collide. Therefore, they collide with less force. The differences between ideal gases and real gases can be viewed most clearly when the pressure is high, the temperature is low, t .....

.... can range from 1 kilometer to about 50 kilometers across. The black crust on the surface of the nuclei helps the comet to absorb heat, which causes some of the ices under the crust to turn to a gas. Pressure builds up underneath the crust and causes the surface to bubble up in some places. Eventually, the weak spots of the crust break open from the pressure, and the gas shoots outward; this is referred to by astronomers as a jet. Dust that had been mixed in with the gas is also pushed out, and as more jets appear, a small gas and dust shell forms around the nucleus, and this is called the coma. The coma, also called the head, is a dense cloud of wat .....

.... males appear and sexual reproduction occurs typically involving the production of resistant, over-wintering eggs. Such eggs are usually enclosed in a purselike ephippium that rests in the sediment at the bottom of the lake or pond until spring at which time the eggs hatch. 1. Daphnia magna. Take a small culture dish to the instructor to receive a few living D. magna. This is a very large species, as go, and one that is easily cultured in the laboratory. Return to your bench and observe the animals using the dissecting microscope. Note the characteristic jerky swimming motion. The uneven appearance of this motion is a result of there being o .....

.... theories, the most important being O'Keefe (1991); Muller, Kubie, Bostock, Taube and Quirk (1991); and Rolls (1991). The behaviourist theories proposed that a reward or aversive object/event will motivate a rat to move towards or away from the location along a reward gradient, and this has been shown to be the case with rats in a maze situation (O'Keefe, 1983). Indeed, this situation does not require the rat to have a concept of absolute space; it may depend on associations between cues and responses which are provided by the maze structure itself. However, O'Keefe & Nadel (1978) identified spatial behaviours which they argued would req .....

.... of matter, also known as atoms. He then returned to Woolsthorpe and continued to study light, gravity and mathematics. These studies eventually lead him to some of the greatest discoveries in the history of science. In science his main discovery was that when white light passed through a prism, it was broken up into a broad spectrum of colors. When that spectrum was shone back through another prism that spectrum became a white light again. Next he passed a single color of light through a prism, the color was the same when it came out the other end this led him to believe that white light was composed of all the colors. During this time he also .....

.... Hipocrates was the first to describe it. He used bandages to treat it. As time progressed so did the treatment methods. In about 1743 gentle stretching was recommended. During that same century, a mechanical device resembling a turnbuckle was used to help stretch the tendons. By this time was pretty well known around the world, using the typical stretching and splinting methods. In the 1800’s plaster of paris was first introduced, and later that same century, the introduction of aseptic technique and anasthesia diminished, but not eliminated infection. As the 70’s and 80’s rolled around, other more reliable methods were depended upon. .....

.... it may lead to the development of drugs that would stimulate the formation of new brain cells in people with Alzheimer's or other diseases where brain cells degenerate, he commented. Goldman noted that the use of drugs to stimulate proliferation of new brain cells will probably result in a more successful strategy than attempting to grow the cells outside the body and then placing them back into the brains of patients, as some scientists have suggested. Goldman, of Cornell University Medical College in New York, and colleagues surgically extracted brain cells from the hippocampus of eight living male patients, ranging i .....

.... for natural values in the face of such uncertainty and respect the 'precautionary principal'." - Ontario Minister of Natural Resources, 1991 The History of the Forest Forests have long been recognized as having vast power, both through their potential and how it has been viewed by humans, as well as through their effect on humans in sometimes subtle ways. The inherent properties of wood have always made it attractive as a versatile resource but there are other, more subtle ways in which it affects people. The tropical rainforests, responsible for producing most of the earth's breathable air, have been given the lofty title of "lungs of the .....

.... atoms electrically neutral. If this balance is disturbed by gain or loss of electrons, the atoms will become electrically charged and are called ions. Electrons occupy energy states. Each level requires a certain amount of energy. For an electron to move to a higher level, it will require the right amount of energy. Electrons can move between different levels and between different materials but to do that, they require the right amount of energy and an "empty" slot in the band they enter. The metallic conductors have a lot of these slots and this is where the free electrons will head when voltage (energy) is applied. A simpler way to look at this is t .....

.... are considerable, so may be the potential dangers. For example, the introduction of cancer-causing genes into a common infectious organism, such as the influenza virus, could be hazardous. We have come to believe that all human beings are equal; but even more firmly, we are taught to believe each one of us is unique. Is that idea undercut by cloning? That is, if you can deliberately make any number of copies of an individual, is each one special? How special can clones feel, knowing they were replicated like smile buttons. "We aren't just our genes, we're a whole collection of our experiences," says Albert Jonsen. But the idea, he adds, raise .....