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Search results 11 - 20 of 278 matching essays
- 11: Cfcs Cause Deterioration of the Ozone Layer
- ... last region is the thermosphere. The thermosphere's outermost edge is roughly 600 miles above the surface of the earth. Beyond it, the airless vacuum of space begins. Oxygen is made up of two oxygen atoms that are bonded together. In the periodic table it is represented by O2. Like oxygen, ozone is a gas that is made up of oxygen atoms. However, a molecule of ozone is made up of three atoms of oxygen bonded together, therefore, O3, represents ozone. The ozone makes up only .01% of the atmosphere. Furthermore, 90% of the ozone is found in the stratosphere. It is concentrated in a layer between ...
- 12: Solar Cells
- ... charge. Every atom has the same number of electrons as there are protons, so, on the whole, it is electrically neutral. The electrons have discrete kinetic energy levels, which increase with the orbital radius. When atoms bond together to form a solid, the electron energy levels merge into bands. In electrical conductors, these bands are continuous but in insulators and semiconductors there is an "energy gap", in which no electron orbits can exist, between the inner valence band and outer conduction band [Book 1]. Valence electrons help to bind together the atoms in a solid by orbiting 2 adjacent nucleii, while conduction electrons, being less closely bound to the nucleii, are free to move in response to an applied voltage or electric field. The fewer conduction electrons ... semiconductors decreases as the temperature is raised or the material illuminated. The excitation of valence electrons to the conduction band is best accomplished when the semiconductor is in the crystalline state, i.e. when the atoms are arranged in a precise geometrical formation or "lattice". At room temperature and low illumination, pure or so-called "intrinsic" semiconductors have a high resistivity. But the resistivity can be greatly reduced by "doping", ...
- 13: Solar Cells
- ... charge. Every atom has the same number of electrons as there are protons, so, on the whole, it is electrically neutral. The electrons have discrete kinetic energy levels, which increase with the orbital radius. When atoms bond together to form a solid, the electron energy levels merge into bands. In electrical conductors, these bands are continuous but in insulators and semiconductors there is an "energy gap", in which no electron orbits can exist, between the inner valence band and outer conduction band [Book 1]. Valence electrons help to bind together the atoms in a solid by orbiting 2 adjacent nucleii, while conduction electrons, being less closely bound to the nucleii, are free to move in response to an applied voltage or electric field. The fewer conduction electrons ... semiconductors decreases as the temperature is raised or the material illuminated. The excitation of valence electrons to the conduction band is best accomplished when the semiconductor is in the crystalline state, i.e. when the atoms are arranged in a precise geometrical formation or "lattice". At room temperature and low illumination, pure or so-called "intrinsic" semiconductors have a high resistivity. But the resistivity can be greatly reduced by "doping", ...
- 14: Solar Cells
- ... charge. Every atom has the same number of electrons as there are protons, so, on the whole, it is electrically neutral. The electrons have discrete kinetic energy levels, which increase with the orbital radius. When atoms bond together to form a solid, the electron energy levels merge into bands. In electrical conductors, these bands are continuous but in insulators and semiconductors there is an "energy gap", in which no electron orbits can exist, between the inner valence band and outer conduction band [Book 1]. Valence electrons help to bind together the atoms in a solid by orbiting 2 adjacent nucleii, while conduction electrons, being less closely bound to the nucleii, are free to move in response to an applied voltage or electric field. The fewer conduction electrons ... semiconductors decreases as the temperature is raised or the material illuminated. The excitation of valence electrons to the conduction band is best accomplished when the semiconductor is in the crystalline state, i.e. when the atoms are arranged in a precise geometrical formation or "lattice". At room temperature and low illumination, pure or so-called "intrinsic" semiconductors have a high resistivity. But the resistivity can be greatly reduced by "doping", ...
- 15: Atomic Theory
- Atomic Theory Atomic Theory is the study of atoms. Atoms are the smallest forms of matter that can still be considered/recognized as elements. Atoms are what make up everything on our earth, from molecules to monkeys. Atoms are joined together to make molecules, which are in turn joined together to make everything else. To give you an idea ...
- 16: Lasers
- ... light energy, produce another photon. This production of the second photon doubles the amount of light energy present, which is called amplification. The only way for stimulated emission to occur is if most of the atoms are in their exited state, which means the atoms have a higher amount of energy than normal. More atoms must exist in the excited state than in the ground state (opposite of exited state) for amplification to occur. When more atoms are in their excited state than in he ground state it is ...
- 17: Daltons Atomic Theory
- ... the sizes of the particles making up different gases must be different. Dalton's exceptional gift for recognizing and interpreting patterns in experimental data lead him from a problem in meteorology to the idea of atoms as fundamental constituents of matter. He realized the vital theoretical connection between atomic weights and weight relations in chemical reactions. He was the first to associate the ancient idea of atoms with stoichiometry. The existence of atoms was first suggested more that 2000 years before Dalton's birth. (Newton's speculations about atoms in the Principia were carefully copied by hand into Dalton's notebooks.) Atoms of an element cannot be ...
- 18: Nuclear Energy
- ... the more we can control the world in which we live. Nuclear energy is contained in the center, or nucleus of an atom. This energy is also known as atomic energy because its obtained from atoms, unfortunately this is not a good choice of words (because many other energies are obtained from atoms). An atomic bomb explosion shows just how powerful muclear energy really is. Such as the underwater explosion of an atomic bomb at Bikini during 1946. This powerful type of energy comes from many things such as atoms and subatomic particles; an atom is a tiny bit of matter that has very little weight. They are much too light to be weighed directly, but scientists have developed methods of determining these tiny ...
- 19: Superconductivity
- ... well. They are called conductors. Others conduct electricity partially and they are called semi-conductors. The concept of electric transmission is very simple to understand. The wire that conducts the electric current is made of atoms which have equal numbers of protons and electrons making 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 ...
- 20: Rustproofing
- ... in dry conditions. Obviously vehicles experience varied conditions and so neither of these types of products are suited for vehicle rust prevention. Under normal conditions the metal of a vehicle contains a mass of Iron Atoms, Impurities and Free Electrons. The impurities are slightly positively charged and therefore there is a potential difference (voltage) between the impurity atoms and the iron atoms. This means that the Iron Atoms become the Cathodes (-) and the Impurity Atoms the Anodes (+). The potential difference usually averages at about 1.1 Volts Because the Impurity Atoms are at a higher potential ( ...
Search results 11 - 20 of 278 matching essays
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