# Cultural Literacy: Physical Science

The New Dictionary of Cultural Literacy

Section: Physical Sciences an Mathematics

## Terms

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Dehydration
The removal of water; in themistry, the loss of two hydrogen atoms for every oxygen atom.
Brownian motion
The erratic motion, visible through a microscope, of small grains suspended in a fluid. The motion results from collisions between the grains and atoms or molecules in the fluid. It was first explained by Albert Einstein
Big Bang Theory
In astronomy, a theory according to which the universe began billions of years ago in a single event, similar to an explosion. There is evidence for it in the observed red shift of distant galaxies, which indicates that they are moving away from the Earth, in the existence of comid microwave background, and from other date. Scientists have recently found that expansion of the universe is actually speeding up..
Celsius
A temperature scale, also called centigrade, according to which water freezes at zero degrees and boils at one hundred degrees.
Dark Matter
Unseen matter that may make up more than ninety percent of the universe. As the name implies, it does not interact with light or other electromagnetic radiation, so it cannot be seen directly, but can be detected by measuring its gravitational effects. It is believed that it was instrumental in forming galaxies in the Big Bang.
Amplitude
In physics, the height of a crest of a wave.
Astronomy
The science that deals with the universe beyond the Earth. It describes the nature, position, and motion of the stars, planets, and other objects in the skies, and their relation to the Earth.
Atomic Number
The number of protons or electrons normally found in an atom of a given chemical element. The higher, the heavier the atom is. In a neutral atom, the number of protons and electrons is the same.
Combustion
Burning; a chemical reaction that involves the rapid combination of a fuel with oxygen.
Absolute Zero
The lowest temperature that can be attained by matter, corresponding to the point at which most motion in atoms stops. It is about -273 degrees on the Celsius scale and about -460 on the Fahrenheit scale.
The molecular attraction that holds the surfaces of two dissimilar substances together.
Convection
The motion of warm material that rises, cools off, and sinks again, producing a continuous circulation of material and transfer of heat. Some examples of process involving it are boiling water, in which heat is transferred from the stove to the air; the circulation of the atmosphere of the Earth, transferring heat from the equator to the North Pole and South Pole; and plate tectonics, in which heat is transferred from the interior of the Earth to its surface.
Black Hole
In Astronomy, an object so massive that nothing, not even light, can escape its gravitation. They were given their name becuase they absorb all the light that falls on them. The existence was first predicted by the general Theory of Relativity. Supermassive ones have been found in the centers of many galaxies. Stellar ones are thought to arise from the death of very massive stars.
Asteroid
A small planet that revolves around the sun. The largest one is only about six hundred miles in diameter.
Cold Fusion
The fusion of hydrogen atoms into helium at room temperature. In 1989 two scientists announced that they had produced it in their laboratory, an achievement that, if true, would have meant a virtually unlimited cheap energy supply for humanity. When other scientists were unable to reproduce their results, the scientific community concluded that the original experiment had been flawed.
Acute Angle
An angle that measures less than ninety degrees but more than zero degrees.
The Celsius temperature scale.
Capillary
A thin tube, such as a blood vessel or a straw, through which fluids flow.
Cohesion
The molecular attraction or joining of the surfaces of two pieces of the same substance.
(Marie) Curie
A French chemist of the late nineteenth and early twentieth centuries, born in Poland. With her husband, Pierre, she discovered the element Radium. She was the first major female scientist of modern times. She was the only person ever to win the Nobel Prize in two different sciences.
Cosmology
The branch of science dealing with the large-scale structure, origins, and development of the universe.
Astronomical Unit
The mean distance between the Earth and the Sun, about 98 million miles or 150 million kilometers.
Atomic Clock
The most accurate clock available. Time is measured by the movement of electrons in cesium atoms. The standard second is now defined by measurements on this.
Dark energy
An as yet unknown and unidentified form of energy that pervades the universe and produces a force that counteracts the gravitational attraction between galaxies. It is thought to be responsible for the accelerating universe.
Algebra
A branch of mathematics marked chiefly by the use of symbol to represent numbers, as in the Pythagorean Theorem.
Apogee
In astronomy, the point during the orbit of a satellite, such as the moon, at which it is farthest from the body being orbited. For planets in the solar system orbiting the sun, their farthest point from the sun is referred to as aphelion.
Coriolis effect
An apprent force ultimately due to the rotation of the Earth. It is the effect that makes the air in storms rotate counterclockwise in the northern hemisphere and clockwise in the southern hemisphere.
Carbon 14
A radioactive isotope of carbon. It contains six protons, six electrons, and eight neutrons. It is produced when neutrons bombard atoms of nitrogen. It is used in a common form of radioactive dating to determine the age of ancient objects.
High-energy electrons, carrying a negative charge, that are sent out by some radioactive nuclei. It can pass through clothing and wooden walls.
Baconian method
A method of experimentation, created by the namesake in the seventeenth century, that derives its conclusions from observed facts rather than from previous conclusions or theories.
Calculus
The branch of mathematics, usually studied after algebra, that provides a natural method for describing gradual change.
Density
The relative heaviness of objects, measured in units of mass or weight per units of volume.
Covalent Bond
A chemical bond in which two atoms share some of their valence electrons, thereby creating a force that holds the atoms together.
Center of Gravity
The point in any solid where a single applied force could support it; the point where the mass of the object is equally balanced. When a man on a ladder leans sideways, so far that this is no longer over his feet, he begins to fall.
Accelerating Universe
A phrase used to refer to the discovery that the Hubble expansion is not slowing down, as one would expect if only gravity were acting on the galaxies, but is actually speeding up as time goes by.
The assimilation of a gas, liquid, or dissolved substance by the surface of a solid.
Base
Any of a number of bitter-tasting, caustic materials. It is the opposite of an acid and has a pH of 7 to 14. A given amount added to an acid neutralizes the acid; water and a salt are produced.
Colloid
A substance made up of particles that are larger than most molecules; these particles do not actually dissolve in substances but stay suspended in them. Fog, paints, and foam rubber are examples.
Antimatter
In physics, matter made of antiparticles.
Buffer
In Chemistry, the components of a solution that can neutralize either an acid or a base and thus maintain a constant pH. They are often used in medications designed to decrease acidity in the stomach.
(Niels) Bohr
A Danish physicist of the twentieth century. He was one of the founders of quantum mechanics and the originator of his namesake atom.
Catalyst
In chemistry, a substance that causes a chemical reaction to occur but is not itself involved in the reaction.
Big Dipper
A constellation in the northern sky. The two stars on the far end of the bowl point towards the North Star. It is part of the constellation Ursa Major (the Great Bear).
Calorie
The amount of heat required to raise the temperature of a kilogram of water by one degree Celsius. It is a measurement of the heat needed to raise the temperature of a gram of water, rather than a kilogram.
Constellation
An easily recognized group of stars that appear to be located close together in the sky and that form a picture if line connecting them are imagined. They are usually named after an animal, a character from mythology, or a common object.
Particles sent out by some radioactive nuclei, each particle consisting of two protons and two neutrons bound together. They carry positive charges.
Axis
In Geometry, a straight line about which an object may rotate or that divides an object into symmetrical halves.
Blackbody
An object that can absorb and send off radiation with complete efficiency--that is, it reflects none of the radiation that falls on it. The higher the object's temperature, the higher the frequency of the radiation it gives off.
Cyclotron
The first kind of particle accelerator built.
Aerodynamics
The branch of science devoted to the study of the flow of gases around solid objects. It is especially important in the design of cars and airplanes, which move through the air.
British thermal unit
A unit for measuring heat. One raises the temperature of one pound of water one degree Fahrenheit.
Boiling Point
The temperature at which a given material changes from a liquid to a gas. It is the same temperature as the condensation point.
Astrophysics
The branch of astronomy devoted to the study of the physical characteristics and composition of objects in the sky. Typical patterns are how much light the stars give off and the size, mass, and temperature of planets and stars.
CFC
(Abbr.) Chemical compounds originally developed for use in refrigeration systems, now used widely in industry. When released into the air, they break down and release chlorine, which causes damage to the Earth's ozone layer and is responsible for creating the ozone hole.
Alkali
A bitter, caustic mineral often found in large beds in the desert. They are bases; two common examples are lye and ammonia. Plants have difficulty growing in soil that is rich in the mineral.
Acid
A sour-tasting material that dissolves metals and other materials. Technically, a material that produces positive ions in solution. It is the opposite of a base and has a pH of 0 to 7.
Diffraction
The breaking up of an incoming wave by some sort of geometrical structure--for example, a series of slits--followed by reconstruction of the wave by interference.
(Nicolaus) Copernicus
A Polish cleric and scholar of the sixteenth century. In 1543 he produced the first workable model of the sun and planets that had the sun at the center.
Andromeda
In astronomy, the galaxy nearest to the Milky Way, usually seen as a large collection of stars arranged in a central core with spiral arms. It was given its name because the stars of the constellation with the same name appear to enclose it.
Buoyancy
The force that causes objects to float. According to the principle of Archimedes, when a solid is placed in a fluid, it is subject to an upward force equal in magnitude to the weight of the fluid it has displaced.
Asteroid Belt
A region of the solar system between the orbits of the planets Mars and Jupiter.
Acceleration
A change in the velocity of an object. The most familiar kind is a change in the speed of an object.
Centrifugal Force
A force that tends to move objects away from the center in a system undergoing circular motion. It keeps the water in a whirling bucket from spilling or throws a rider in a car against the door when the car goes around a sharp curve.
Cardinal Numbers
Numbers that indicate the quantity of things in a group or set, but not the order or arrangement of those things. One, two, and one thousand are examples.
Antiparticle
In physics, a rare form of subatomic matter that is a mirror image of normal matter. Corresponding to an electron, it is a positron, which has the same mass as an electron but a positive charge. Antiprotons have the same mass as protons but have a negative charge. When matter and antimatter come together, the two particles annihilate each other, converting their mass into energy or into other types of particles.
Algorithm
A set of instructions for solving a problem, especially on a computer. One for finding the total of a grocery bill would direct you to add up the costs of individual items.
Critical Mass
In physics, the amount of material that must be present before a chain reaction can sustain itself. It is used to refer generally to the minimum amount of something needed to produce a given effect.
Carbon
A chemical element; its symbol is C. The nucleus has six protons and six or more neutrons; six electrons are in orbit around the nucleus. They form the basis for all living tissue.
Alchemy
A science that sought to transform one chemical element into another through a combination of magic and primitive chemistry. It is considered to be the ancestor of modern chemistry.
Cobalt 60
A radioactive isotope produced when neutrons bombard atoms of the element. It is a common substance used in radiation therapy for cancer.
Axiom
In mathematics, a statement that is unproved but accepted as a basis for other statements, usually because it seems so obvious.
Comet
An object that enters the inner solar system, typically in a very elongated orbit around the sun. Material is boiled off from it by the heat of the sun, so that a characteristic tail is formed. The path of one can be in the form of an ellipse or a hyperbola. If it follows a hyperbolic path, it enters the solar system once and then leaves forever. If its path is an ellipse, it stays in orbit around the sun.
Atom
A unit of matter; the smallest unit of a chemical element. Each one consists of a nucleus, which has a positive charge, and a set of electrons that move around the nucleus.
Conduction
Transfer of energy through a medium without any apparent change in the medium.
Centimeter
A unit of length in the metric system; one-hundredth of a meter, or about two-fifths of an inch.
Diffusion
The spreading of atoms of molecules of one substance through those of another, especially into liquids or gases.
Archimedes
An ancient Greek scientist, mathematician, and inventor. He is best known for his investigations of buoyancy.
Alloy
A material made of two or more metals, or of a metal and another material. Brass is one of copper and zinc; steel is one of iron and carbon. They often have unexpected characteristics. In the examples given above, brass is stronger than either copper or zinc, and steel is stronger than either iron or carbon.
Decibel
A unit of measurement of the volume of sounds.

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