Beyond the God Particle by Leon M. Lederman, Christopher T. Hill Read Free Book Online Page B

100 atoms found in nature (slightly more than 100 atoms is today's count; it was significantly fewer at the time of Mendeleev; many elements, such as helium, were discovered later, and many of the heaviest elements are so radioactively unstable that they must be artificially produced in particle accelerators and are not to be found on our old high school chemistry classroom wall charts). The Periodic Table represented a pattern of repetitive chemical behavior in the properties and forms of atoms as one goes to heavier and heavier atoms. By its complexity, however, it suggested that atoms may, themselves, be further reduced and may have internal structure, and that a deeper layer of subatomic matter must exist. 3

    THE “PHYSICS AS AN ONION” METAPHOR
    Mendeleev's table was the beginning of the modern era of the science of matter. To understand this, one must appreciate that nature is, empirically, organized much like an onion. Nature has different layers of phenomena and structures as one descends to smaller and smaller distance scales. And, going downward to shorter distances, we discover, is equivalent to going to higher and higher energy scales (higher “energy per particle”; we'll define this more carefully momentarily). Although all of nature is governed by the same underlying fundamental laws of physics, the structures of complexity that we see in nature seemingly occur at different “strata” of phenomena, like an onion, and each stratum of nature is characterized by the energy needed to probe it.
    What do we mean by “the energy needed to probe it”? We have to get a little bit technical here and introduce you to the common currency in talking about energies of fundamental particles and atoms: the electron volt or “eV.” 4 Most of the science of chemistry, that is, the amount of energy involved in most chemical reactions, lies in the range from about 0.1 to 10 eV per atom. This means that when a given atom enters into a chemical bond with another atom (or an existing molecule) to form a new molecule, roughly 0.1 to 10 eV of energy is released. This is energy that comes from the forces that produce a chemical bond between two atoms, and it is typically released in the form of light, or the energy of motion, called kinetic energy .
    The released energy is usually converted into heat (which is the aggregate random motion of atoms in a material), but it can also be seen as the light emitted from a fire or heard as the boom from a firecracker. You can usually see the released chemical energy with your eyes because a single visible particle of light, the photon , carries about 2 to 3 eV of energy—after all, the light entering our visual system that allows us to see is processed by various chemical reactions in our eyeballs and our brain, and so the perception of light entirely happens at the chemical energy scale.
    If we can probe molecules with a source of energy of about 0.1 to 10 eV, we can often cause a chemical reaction to occur. For example, striking a match in a mixture of methane (CH 4 ) and oxygen (O 2 ) will provoke a rapid chemical reaction—a flame—yielding carbon dioxide (CO 2 ) and water (H 2 O). 5 The match is generating photons and kinetic energy of motion of atoms of about an eV each from its own burning (usually oxygen combiningwith phosphorous). These energetic particles strike the methane and oxygen and nudge them into reacting, which emits more photons. Then more and more energy is released in a chemical chain reaction, and VAVOOM , you might have an explosion.
    The physics, that is, the motion and interactions of electrons and atoms in chemical reactions— the stratum of the chemical reactions —is very much independent of, or decoupled from, what is going on in other stratums of nature. For example, to analyze everyday chemical phenomena, one need not be bothered by such complications as the detailed motion of the protons and neutrons that comprise the inner atomic nucleus and that