Science & Philosophy: Formate to Gastropoda
Structural Formula - Complete Structural Formulas, Line Formulas, Three Dimensional Formulas - Condensed structural formulas
There are several different ways to represent compounds in structural formulas, depending on how much detail needs to be shown about the molecule under consideration. Illustration by Hans & Cassidy. Courtesy of Gale Group. We will look at complete structural formulas, condensed formulas, line formulas, and three-dimensional formulas. After you become familiar with the rules for w…
Fossa
Fossas are cat-like Madagascan carnivores in the family Viverridae, which also includes civets, linsangs, genets, and mongooses. Fossas are quite different from other viverrids and are the sole members of the subfamily Cryptoproctinae. They are the largest Madagascan carnivores, measuring 24-30 in (60-75 cm) long. With a number of cat-like features-including a rounded head, long whiskers, large fr…
Fossil and Fossilization - The Fossil Clock, From Biosphere To Lithosphere, From Field To Laboratory, Interpreting The Fossil Record
Fossils are a significant window into Earth's history and organic evolution. The term fossil literally means something that has been 'dug up,' but its modern meaning has been restricted to evidence of past life. Such evidence may take the form of body fossils (both plant and animal), trace fossils or ichnofossils (physical features formed in rock due to animal-sediment interac…
Fossil Fuels
Fossil fuels are buried deposits of petroleum, coal, peat, natural gas, and other carbon-rich organic compounds derived from the dead bodies of plants and animals that lived many millions of years ago. Over long periods of time, pressure and heat generated by overlying sediments concentrate and modified these materials into valuable energy sources for human purposes. Fossil fuels currently provide…
Foundationalism - Two-tier Structure Of Justification, An Objection, Outstanding Challenges, Bibliography
When reasons are beliefs, we have inferential justification: one belief is justified on the basis of another belief. How is the latter, supporting belief itself justified? Is another supporting belief always needed? According to foundationalism, another supporting belief is not always needed. …
Fractal
A fractal is a geometric figure, often characterized as being self-similar; that is, irregular, fractured, fragmented, or loosely connected in appearance. Benoit Mandelbrot coined the term fractal to describe such figures, deriving the word from the Latin "fractus" meaning broken, fragmented, or irregular. He also pointed out amazing similarities in appearance between some fractal se…
Common Fraction - Operations with fractions
Fraction is the name for part of something as distinct from the whole of it. The word itself means a small amount as, for example, when we ask someone to "move over a fraction." We mean them to move over part of the way, not all the way. Fractional parts such as half, quarter, eighth, and so on form a part of daily language usage. When, for example, we refer to "half an hour,&…
Fraunhofer Lines
Fraunhofer lines are dark absorption lines in the solar spectrum that can be seen when sunlight is passed through a prism to separate it into the colors of the rainbow. They occur because cooler gas, which is higher in the Sun's atmosphere, absorbs some colors of the light emitted by hotter gas lower in the Sun's atmosphere. Sir Isaac Newton (1642-1727) discovered that if white light…
Freeway - Rise Of The Freeway, Features Of The Freeway, Safety Features - Construction of a freeway
Freeways, also called superhighways, are roads specifically designed to allow for the free flow of traffic. Freeways typically feature two or more traffic lanes in each direction, medians to divide the opposing directions, full access control, a system of ramps to prevent merging and diverging traffic from interrupting the traffic flow, and grading to separate intersecting traffic on other roads. …
Frequency
Any process that is repetitive or periodic has an associated frequency. The frequency is the number of repetitions, or cycles, during a given time interval. The inverse of the frequency is called the period of the process. Pendulums, as in a grandfather clock, also have a frequency of a certain number of swings per minute. A complete oscillation for a pendulum requires the pendulum bob to start an…
Freshwater
Freshwater is chemically defined as containing a concentration of less than two parts per thousand (<0.2%) of dissolved salts. Although water is abundant on the surface of Earth, freshwater is a very limited resource. Freshwater, in all forms, makes up less than 2.8% of the world water supply. Freshwater on Earth exists in several forms. These include lakes, which represent 0.009% of the gl…
Friction
Friction is the force that resists motion when the surface of one object slides over the surface of another. Frictional forces are always parallel to the surfaces in contact, and they oppose any motion or attempted motion. No movement will occur unless a force equal to or greater than the frictional force is applied to the body or bodies that can move. While friction is often regarded as a nuisanc…
Frigate Birds
A frigate bird on its nest on Barbuda Island in the West Indies. Photograph by Ormond Gigli. Stock Market. Reproduced by permission. Frigate birds are five species of oceanic birds that make up the family Fregatidae. Frigate birds occur along the coasts of the tropical oceans, but also hundreds of miles out to sea. Frigate birds typically weigh about 3 lb (1.5 kg), but the spread of their l…
Frog's-Bit Family
The frog's-bit or tape-grass family (Hydrocharitaceae) is a relatively small group of herbaceous, aquatic, monocotyledonous plants, occurring in fresh and marine waters. There are about 100 species in the frog's-bit family, distributed among 15 genera. The flowers of members of this family are water pollinated, shedding their pollen into the water, which disperses it to the stigmatic…
Frogs - History And Fossil Record, Adult Morphology, Ecology, Life History And Behavior, Classification, Frogs And Humans - Morphology, Larval morphology
Frogs are tail-less amphibians (class Amphibia, order Anura). With some 3,500 living species, frogs are the most numerous and best known of amphibians. They are found on all continents except Antarctica and are common on many oceanic islands. The terms "frog" and "toad" are derived from early usage in England and northern Europe, where two families of the order Anura oc…
Fuel Cells - Types of fuel cells
Fuel cells are a clean and quiet way to convert chemical-energy of fuels directly into electricity. Specifically, they transform hydrogen and oxygen into electric power, emitting water as their only waste product. A fuel cell consists of two electrodes, an anode and a cathode, sandwiched around an electrolyte. (An electrolyte is a substance, usually liquid, capable of conducting electricity by mea…
Fundamentalism - Origins, Political And Cultural Developments, Gush Emunim In Israel, Islamic Revolution In Iran, Bharatiya Janata Party In India
A term used loosely to describe a reaction of (neo)traditional religion against the pressures of modernity, fundamentalism became a widespread topic of interest in the media and the academy during the last quarter of the twentieth century. According to many observers, fundamentalism is a worldwide phenomenon, arising in various societies with differing cultural backgrounds and experiences of moder…
Fungicide
A fungus is a tiny plant-like organism that obtains its nourishment from dead or living organic matter. Some examples of fungi include mushrooms, toadstools, smuts, molds, rusts and mildew. Fungi have long been recognized as a serious threat to plants and crops. They attack food both while it is growing and after it has been harvested and placed in storage. One of the great agricultural disasters …
Futurology - Objectives And Characteristics, Bibliography
Futurology is the study of the future to obtain knowledge of it on the basis of present trends. Beginning in the 1960s, it is a relatively new field of study. The word futurology was first used in 1943 by Ossip Flechteim, a political scientist, to describe a new scientific field of human knowledge based on a critical, systematic, and normative analysis of questions related to future. However, fut…
Gaia Hypothesis - Evidence in support of a Gaian Earth
Gaia, Earth, was believed by the ancient Greeks to be a living, fertile ancestor of many of their important gods. The Romans, who adopted many Greek gods and ideas as their own, also believed in this organismic entity, who they renamed Terra. The Gaian notion has been personified in more recent interpretations as "Mother Earth." The Gaia hypothesis is a recent and highly controversia…
Gamete
A gamete is a specialized reproductive cell. The cells usually have one half as many chromosomes in their nuclei as the majority of body cells, which are known as somatic cells. All sexually-reproducing plants, animals, and microbes produce gametes sometime during their life span. During the second and third quarters of the nineteenth century the scientists J. L. Prevost, J. B. Dumas, T. Schwann, …
Gametogenesis
Gametogenesis is the production of haploid sex cells (in humans, ovum and spermatozoa) that each carry one-half the genetic compliment of the parents from the germ cell line of each parent. The production of ovum is termed oogenesis and the production of spermatozoa is called spermatogenesis. Both oogenesis and spermatogenesis provide a mechanism through which genetic information may be passed to …
Gamma-Ray Astronomy
Gamma rays are a highly energetic form of electromagnetic radiation. The wavelength of a gamma ray is very short—less than the radius of an atom—the energy they carry can be millions of electron volts. Gamma rays originate in the nucleus of an atom, and are created when cosmic rays collide with atoms in molecules of gas. In the collision, the nucleus of the atom is destroyed, and gam…
Gamma Ray Burst
Gamma ray bursts are brief, seconds-long, blasts of radiation of mysterious origin that, in nature, seem to come from the depths of interstellar space. Bursts of gamma radiation also have been measured coming from severe thunderstorms and are a component of nuclear bomb detonation. The accidental discovery of cosmic gamma ray bursts was confirmed in 1973. Ten years earlier, the United States Air F…
Garden - Death, Time And Temporality, Order And Plenty, The Lost Home, Garden As Paradise And Enclosure. - Gardens in the History of Ideas
The term garden, which is of Germanic origin, means "yard" or "enclosure" and denotes ways of organizing earth, water, plants and, sometimes, people, animals, and art (sculpture, architecture, theater, music, and poetry), the formal qualitities of which are determined as much by pleasure, artistry, or aesthetics as by convenience or necessity. This definition excludes a…
Garpike
Garpike (gar) are bony fish classified in the family Lepisosteidae. These fish are differentiated from garfish which belong to the family Belonidae. Garpike were once Longnose gar (Lepisosteus osseus). Photograph by Robert J. Huffman. Field Mark Publications. Reproduced by permission. abundant and widely distributed, but are now rare. Some species of garpike are found in Mexico, Central Am…
Properties of Gases
The fundamental physical properties of a gas are related to its temperature, pressure and volume. These properties can be described and predicted by a set of equations, known as the gas laws. While these laws were originally based on mathematical interpretations for an ideal or perfect gas, modern atomic and kinetic theory of gases has led to a modified expression that more accuratel…