Particle

A particle is a small quantity of matter with measureable properties, such as volume or density. In this sense, a particle can be a small amount of virtually any type of material. To be clear, however, the size of a particle can vary widely. While some particles are too small to be seen even on the microscopic level, others are large enough to be observable with only the naked eye. Particles on the smaller end of the size scale are among the fundamental building blocks of matter.

The Nature of Particles

The exact definition of the term particle varies according to the scientific field through which the concept is studied. The definition provided above most accurately describes particles as they are viewed in physics. To develop a better understanding of the nature of particles as seen from this perspective, it is first necessary to examine their basic classifications.

Particles are primarily classified according to their size. From smallest to largest, these classifications include subatomic, molecular, colloidal, microscopic, and macroscopic. Subatomic particles are the basic particles of which atoms are composed, such as protons, neutrons, and electrons. Atoms and molecules formed by combinations of atoms are molecular particles. Colloidal particles are small particles of matter that can be observed with powerful electron microscopes. Microscopic particles are larger particles that can be observed with the use of a common optical microscope. Finally, macroscopic particles are those that are large enough to be observed with the human eye alone. This article focuses on particles above the subatomic level.

One reason why particles are primarily classified by size is because the size of a particle has a significant bearing on how it interacts with other particles. Specifically, the smaller a particle is, the more it is affected by certain forces of attraction that draw it toward other particles. This means that at smaller sizes, particles are more likely to join with other particles to form larger structures. Ultimately, this leads to the formation of various chemical compounds and other substances.

Larger particles, if only because of the relative ease with which they can be observed, are generally more recognizable to the average person. Water droplets in the atmosphere, grains of sand, pollen, and volcanic ash are all examples of large macroscopic particles. To some scientists, there is no upper limit to the potential size of a particle. From this perspective, even large celestial bodies like asteroids and planets can be considered particles. For practical purposes, however, most scientists only view objects that measure up to one millimeter in size as particles.

The Qualities of Particles

One thing that most particles have in common is the fact that they gradually decay. Over time, most particles break down and eventually divide. Instead of simply being smaller versions of the original particle, these products of decay are entirely new particles. While this type of decay occurs among most types of particles, it does not occur among all particles. Particles that do not naturally decay over time are known as stable particles.

Particles share other unique qualities as well. When a large number of small particles of the same material aggregate or unite, they form a particle system with a large surface area. The surfaces of such particle systems have special properties that are quite different from the bulk form of the material in question. These unique surface properties help to make the materials useful for different practical applications.

Many materials can also be broken down into particulate form for transportation purposes. Grounding a material down into a powder or slurry often makes it easier and more affordable to transport it from one place to another. This type of grounding can also be used to produce pills, which are small, easy to administer capsules containing a precisely measured amount of minerals and medicines in powdered form.

Finally, when particles of a given material are reduced in size to almost the molecular level, their structural, electronic, and optical properties can begin to change. These changes often result in the emergence of new properties not normally found in the material.

The Benefits and Drawbacks of Particles

Particles are an inexorable part of life. All living things are made of particles like cells and proteins. The environment in which we live naturally produces a wide variety of the particulate matter with which we come in contact every day, such as soil and snow. Simply put, particles are a basic fact of life.

Throughout history, people have also used particles to advance human civilization. Indeed particulate matter has often proved useful in the production of new technologies and the development of cutting-edge medical techniques. Today, the list of industrial applications for various forms of particulate matter is virtually endless. Unfortunately, industry is also the source of many of the worst problems we face today in relation to particulate matter.

As the world has become increasingly industrialized, factories have released a dangerous amount of particulate matter into the environment. These particles, often in the form of smoke, smog, and solid waste, cause air pollution, water pollution, and other problems that threaten the environment and human health.

Bibliography

Considine, Glen D, ed. "Particle." Van Nostrand's Encyclopedia of Chemistry. Hoboken, NJ: Wiley-Interscience, 2005. 1208. Print.

Dine, Michael. "Particle." Building Blocks of Matter: A Supplement to the Macmillan Encyclopedia of Physics. Ed. John S. Rigden. New York: Macmillan Reference USA, 2003. 347–49. Print.

"The Particle Adventure: Particle Decays and Annihilations." Berkeley Lab. Web. 29 Dec. 2014. http://www.particleadventure.org/decay‗intro.html

"What is a Particle?" University of Florida Particle Engineering Research Center. Web. 29 Dec. 2014. http://perc.ufl.edu/particle.asp