Online Edition - December 2008
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To refresh our memory in Physics, specifically in the discovery of atoms, it was Democritus in Greece who first mentioned that all materials consist of extremely small indivisible particles (400 B.C). In his time, Democritus’ opinions were rejected by the well known philosopher Aristotle who believed in the four natural elements: earth, air, fire and water. Democritus’ theory of atoms was not entirely accepted for the next two thousand years or so. During the 17th century, British scientist Robert Boyle took mathematics into chemistry and revived the atomic theory. According to Boyle, solids had stronger chemical bonds compared to liquids. He also reasoned that the atoms in solids must be close to each other; this is not true for liquids or air. For instance, air, has space between its atoms. Therefore, we are able to compress air and use it for different applications in our daily. One of the many applications is when trains use compressed air to slow down and stop. Otherwise it would have been impossible to stop a moving train on the rail system. In 1896, scientists found that the atom, which was assumed to be indivisible into any small quantities since the ancient years until the late 1800’s, was actually formed by subatomic particles that were later named as electrons, protons, and neutrons. The field of this study is known as Particle Physics. To better understand the role of Particle Physics we need first to recall some of the fundamentals of Physics. To begin, atoms are made up from three particles: protons have positive charge, electrons, carry negative charge, and neutrons that carry no electrical charge. Protons and neutrons in an atom bond together to form the nucleus of the atom also called the center of the atom. Electrons orbit the nucleus. Since protons repel each other, in each element neutrons must be present in the nucleus at least equal to the number of protons to keep the protons and the nucleus together. In the days following the Second World War, particle physicists invented many scientific instruments in order to find the subatomic particles and investigate their behaviors. An extremely functional device was the “Bubble Chamber”, which was used in the development of particle physics and was invented by Donald Glazer. “Bubble Chamber” helped scientists to observe the reaction between particles. It contained a super-heated liquid that created tiny bubbles along the track of the particles. As the particles moved inside the liquid, they knocked electrons and formed ions. If the liquid was approaching the boiling point, earliest bubbles were formed around these ions. In these experiments, scientists photographed and analyzed the behavior change of the ionized particles. This procedure helped physicists to study nuclear physics and inspect the character of the substance also referred as “matter.” Scientists are investigating matter in subatomic level. In summary, science throughout the centuries has found answers to many previously unknown questions. Today, scientists in particle physics are researching to find out what is “dark matter.” The studies and experiments are made in research centers also called as Large Hadron Colliders. They are several particle accelerator research centers in the world some of them are located in the US as known Brookhaven National Lab, Lawrence Berkeley National Lab and Fermi National Accelerator Laboratory. Most us of already heard about CERN-Large Hadron Collider, which is located in Geneva, Switzerland. Physicists work in these tremendous laboratories to collide particles with one another so they can observe the situation at the instant of the collision and answer to two primary questions of physics: why particles have different masses? Why does anti-matter exist in nature? Whether the researches are taking place in the laboratories of CERN or Brookhaven physicists are keener than ever to find the answer to these questions. |
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