Glossary Terms

technically known as zero kelvins, equals −273.15 degrees Celsius, or −459.67 Fahrenheit, and marks the spot on the thermometer where a system reaches its lowest possible energy, or thermal motion

transfer of the energy of a wave to matter as the wave passes through it

rate at which an object changes its velocity

closeness of a measured value to a standard or known value

substance that will dissolve in water to yield hydronium ions, H3O+

reaction in which a hydrogen ion, H+, is transferred from one chemical species to another

flow of electric charge that periodically reverses direction

instrument for measuring electric current in amperes

distance between the resting position and the maximum displacement of the wave

angle formed between the normal and the incident ray at the point of incidence

angle between reflected ray and the normal at the point of incidence to a reflecting surface

negative ion formed by the loss of electrons

smallest particle of an element that has the properties of that element and can enter into a chemical combination

number of protons in an atom minus the number of electrons

mass of an atom of a chemical element expressed in atomic mass units; it is approximately equivalent to the number of protons and neutrons in the atom (the mass number) or to the average number allowing for the relative abundances of different isotopes

12th of the mass of one carbon-12 atom; 1 amu = 1.6605 ×10−24 g

number of protons in the nucleus of an atom

procedure in which the electron configuration of the elements is determined by “building” them in order of atomic numbers, adding one proton to the nucleus and one electron to the proper subshell at a time

rate at which velocity changes

displacement divided by the time of travel

equation in which equal numbers of atoms for each element involved in the reaction are represented on the reactant (left) and product (right) sides

substance that will dissolve in water to yield hydroxide ions, OH−

one of a set of simple units in a system of measurement that is based on a natural phenomenon or established standard and from which other units may be derived

ionic compounds composed of just two elements, a metal which forms the cations and a nonmetal which forms the anions

positive ion formed by the loss of electrons

temperature scale, also called centigrade, according to which water freezes at zero degrees and boils at one hundred degrees

attraction between atoms or ions that holds them together in a molecule or a crystal

process in which one or more substances are altered into one or more new and different substances with different physical and chemical properties

energy that is produced by breaking or forming chemical bonds between atoms and molecules

symbolic representations of chemical reactions in which the reactants and the products are expressed in terms of their respective chemical formulae

common patterns of reactivity between elements

abbreviation used to indicate an element or an atom of an element

closed loop through which charges can continuously move

pure substances that are comprised of two or more elements

heat transfer through contact between atoms

measure of the ease at which an electric charge or heat can pass through a material

standards to which comparisons are made in an experiment

heat transfer through the movement of gases or liquids

lens that focuses the light rays to a specific point called the focal point

change from one set of units to another, by multiplying or dividing

lens shaped so that all light rays that enter it parallel to its axis cross one another at a single point on the opposite side of the lens

another term for the electrostatic force

mathematical equation calculating the electrostatic force vector between two charged particles

chemical bonds that involve the sharing of electrons to form electron pairs between atoms

point on the medium (wave) that exhibits the maximum amount of positive or upward displacement from the rest position

slowing down or decrease in the magnitude of the velocity of an object; also known as negative acceleration

mass of a unit volume of a material substance

variable that changes as a result of the independent variable manipulation

unit that results from a mathematical combination of SI base units

process that uses conversion factors to convert from one set of units to another

flow of electric charge in only one direction

change in position of an object

magnitude or size of displacement between two positions

lens that causes a beam of parallel rays to diverge after refraction, as from a virtual image; a lens that has a negative focal length

when two pairs of electrons are shared between a pair of atoms

study of forces that cause objects and systems to move

a physical property of an object that causes it to be attracted toward or repelled from another charged object; each charged object generates and is influenced by a force called an electromagnetic force

rate at which charge flows

region around a charged particle or object within which a force would be exerted on other charged particles or objects

energy (both kinetic and potential) in the charged particles of an atom that can be used to apply force and/or do work

object that is temporarily magnetic when an electrical current is passed through it

one of the four fundamental forces of nature; the electromagnetic force consists of static electricity, moving electricity and magnetism

range of wavelengths or frequencies over which electromagnetic radiation extends

form of radiation that travels through the universe; they are created because of vibrations between an electric field and a magnetic field

use of electrical currents to induce magnetism

arrangement of electrons in the orbitals of an atom

measure of the tendency of an atom to attract electrons

negatively charged subatomic particles; together with protons and neutrons they compose all atoms

amount and direction of attraction or repulsion between two charged bodies

pure substances that cannot be broken down into simpler substances by chemical changes

a formula for a compound that indicates the types of atoms present and the simplest whole-number ratio of the number of atoms or ions in the compound

reaction or change that absorbs heat

capacity of a physical system to perform work

change that releases heat

a scientific procedure undertaken to make a discovery, test a hypothesis, or demonstrate a known fact

scale for measuring temperature, in which water freezes at 32 degrees and boils at 212 degrees

materials, such as iron, cobalt, nickel, and gadolinium, that exhibit strong magnetic effects

vector quantity that measures the speed and direction of a moving body after it has reached its maximum acceleration

total energy of a system remains constant, though energy may transform into another form

distance from a lens or mirror to the focal point (F)

point at which all radiation coming from a single direction and passing through a lens or striking a mirror converges, also called focus

push or pull upon an object resulting from the object's interaction with another object

region in which a test particle will experience a force

number of waves that pass a fixed point in unit time

force that resists motion when the surface of one object comes in contact with the surface of another

equals the magnitude of the charge of an electron (e) with e = 1.602 ×10−19 C

potential energy associated with gravitational force

universal force of attraction acting between all matter

energy from the movement of atoms or molecules. It may be considered as energy relating to temperature. Also known as thermal energy

movement of thermal energy that increases the energy of one body and decreases the energy of the other body

mixture with a composition that varies from point to point

a mixture that exhibits a uniform composition and appears visually the same throughout; also called a solution

a testable statement about the relationship between two or more variables or a proposed explanation for some observed phenomenon

variable that stands alone and isn't changed by the other variables you are trying to measure but manipulated by the researcher

value calculated from the ratio of the speed of light in a vacuum to that in a second medium of greater density

a set of base units, derived units, and a set of decimal-based multipliers that are used as prefixes

atom in which the number of subatomic particles is not equal

electrostatic forces of attraction between oppositely charged cations and anions

compound that contains ions and is held together by ionic bonds

compounds with the same chemical formula but different molecular structures

each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element

The SI derived unit used to measure energy or work. One joule is equal to the energy used to accelerate a body with a mass of one kilogram using one newton of force over a distance of one meter

base unit of thermodynamic temperature measurement in the International System of Units (SI). It is represented by the symbol K

base unit of mass in the International System of Units (SI)

study of motion without considering its causes

energy of motion

statements, based on repeated experiments or observations, that describe or predict a range of natural phenomena

total charge is constant in any process

total energy of a system remains constant, though energy may transform into another form

in a closed or isolated system, matter cannot be created or destroyed. It can change forms but is conserved

angle of reflection equals the angle of incidence; θr = θi

light ray always deviates more toward the normal in the optically denser medium

the measurement of the extent of something along its greatest dimension; a measurement of the physical quantity of distance

drawings that describe the bonding in molecules and polyatomic ions

elemental symbol surrounded by one dot for each of its valence electrons

derived unit for the measure of volume for a substance using the metric system

energy that results from a magnetic field

region around a magnetic material or a moving electric charge within which the force of magnetism acts

pictorial representations of the strength and the direction of magnetic fields

isolated magnetic poles; a south pole without a north pole, or vice versa (no magnetic monopole has ever been observed)

phenomenon associated with magnetic fields, which arise from the motion of electric charges

to be turned into a magnet; to be induced to be magnetic

quantity or distance

a dimensionless quantity representing the amount of matter in a particle or object

the difference between the value of an atom's mass in atomic mass units and the atoms actual mass

total number of protons and neutrons in an atom

scientific instrument that analyzes and helps identify the substances in a sample of material

anything that takes up space and can be weighed

the process of obtaining the magnitude of a quantity relative to an agreed standard

sum of the kinetic and potential energy of a body

bonds that result from the electrostatic attraction between metal cations and delocalized electrons

elements that conduct heat and electricity moderately well, and possess some properties of metals and some properties of nonmetals; shaded purple on the periodic table

elements that are shiny, malleable, and good conductors of heat and electricity; shaded yellow on the periodic table

the base unit of length in the International System of Units (SI)

the decimal measuring system based on the meter, liter, and gram as units of length, capacity, and weight or mass

substance composed of two or more types of matter that can be present in varying amounts and can be separated by physical changes

compounds that result when atoms share rather than transfer electrons; also called covalent compounds

representation of a molecule that uses chemical symbols to indicate the types of atoms and subscripts to show the number of each atom of each type in the molecule

sum of atomic masses for all atoms composing the molecule

two or more atoms joined by strong forces called chemical bonds

vector sum of all the forces acting on a system from the outside of the system

particles found in the nucleus of an atom; almost identical in mass to a protons, but carry no electric charge

force needed to accelerate a 1 kg system at the rate 1 m/s squared

a body at rest remains at rest, or, if in motion, remains in motion at a constant velocity unless acted on by a net external force

acceleration of a system is directly proportional to and in the same direction as the net external force acting on the system, and inversely proportional to its mass

whenever one body exerts a force on a second body, the first body experiences a force that is equal in magnitude and opposite in direction to the force that it exerts

elements that appear dull and are poor conductors of heat and electricity; shaded green on the periodic table

end or the side of a magnet that is attracted toward Earth’s geographic north pole

form of energy released from the nucleus, the core of atoms, made up of protons and neutrons

center of an atom composed of protons and neutrons, surrounded by orbiting electrons

: the collecting and recording of data, which enables scientists to construct and then test hypotheses and theories

tendency of main-group atoms to form enough bonds to obtain eight valence electrons is known as the octet rule

an empirical relation stating that the current I is proportional to the potential difference V, ∝ V; it is often written as I = V/R, where R is the resistance

substance allowing no light to pass through

process that occurs when an atom, molecule, or ion loses one or more electrons in a chemical reaction

time it takes for two successive crests (one wavelength) to pass a specified point.  The time it takes the wave to complete one full oscillation

table of the chemical elements arranged in order of atomic number, usually in rows, so that elements with similar atomic structure (and hence similar chemical properties) appear in vertical columns

change in the state or properties of matter without any accompanying change in the chemical identities of the substances contained in the matter

characteristic of matter that is not associated with a change in its chemical composition

bond between different atoms in which electrons are not shared equally

location of an object at any given time

energy that is stored in an object due to its position relative to some zero position

unit of weight in the British engineering system equal to 4.448 newtons that is commonly used in the United States

the repeated multiplication of a factor and the number which is raised to that base factor is the exponent

reaction in which dissolved substances react to form one or more solid products

closeness of two or more measurements to each other

a letter or series of letters attached to the beginning of a word, word base, or suffix to produce a derivative word with a new meaning

qualities and characteristics of individual substances that describe and identify them

positively charged particles that, together with the electrically neutral particles called neutrons, make up the nucleus of an atom

covalent bonds in which electrons are shared equally between atoms within the compound

substance for which all specimens have exactly the same makeup and properties

energy emitted by electromagnetic waves that travel through space without any medium

heat transfer through electromagnetic waves

a beam of light or radiation

image in which light rays from one point on the object actually cross at the location of the image and can be projected onto a screen, a piece of film, or the retina of an eye

reactions that involves the transfer of electrons between chemical species; also known as oxidation-reduction reactions

process in which a chemical species decreases its oxidation number, usually by gaining electrons

change in direction of a wave front at an interface between two different media so that the wave front returns into the medium from which it originated

change in direction of a wave passing from one medium to another caused by its change in speed

electric property that impedes current

object that has simple resistance

a collection of principles and procedures for the systematic pursuit of knowledge involving the recognition and formulation of a problem, the collection of data through observation and experiment, and the formulation and testing of hypotheses

a way of writing very large or very small numbers

SI Unit for time; 1/86,400 of the time that it takes the Earth to rotate once on its axis

repetitive movement back and forth through an equilibrium, or central, position, so that the maximum displacement on one side of this position is equal to the maximum displacement on the other side

mechanical device that allows you to do the same amount of work with reduced effort by increasing the distance traveled to decrease the force; the six basic simple machines are the wheel and axle, inclined plane (or ramp), pulley, lever, wedge and the screw

when a pair of atoms shares one pair of electrons

a mixture that exhibits a uniform composition and appears visually the same throughout; also called a homogeneous mixture

form of kinetic energy caused by the physical vibration of air particles or molecules

pattern of disturbance caused by the movement of energy traveling through a medium (such as air, water or any other liquid or solid matter) as it propagates away from the source of the sound

end or the side of a magnet that is attracted toward Earth’s geographic south pole

rate of change of position of an object in any direction

distinct forms in which matter can exist

a buildup of electric charge on the surface of an object

formula for a compound that gives the types and numbers of atoms in the molecule and shows how the atoms are connected in the molecule

a measure of the average kinetic energy of the particles in an object

carefully thought-out explanations for observations of the natural world that have been constructed using the scientific method, and which brings together a myriad of facts and hypotheses

energy from the movement of atoms or molecules. It may be considered as energy relating to temperature; also referred to as heat

lens whose thickness allows rays to refract but does not allow properties such as dispersion and aberrations

interval over which change occurs

passage of electromagnetic radiation through a medium

substance allowing light to pass through without appreciable scattering of light

when three electron pairs are shared by a pair of atoms

point on the medium (wave) that exhibits the maximum amount of negative or downward displacement from the rest position

a range of possible values within which the true value of the measurement lies

a particular physical quantity, defined and adopted by convention, with which other quantities of the same kind are compared to express their value

outer electrons of an atom that have the highest energy and are more easily lost or shared than the core electrons

quantity that has both magnitude and direction

directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time

image that is on the same side of the lens as the object and cannot be projected on a screen

electrical potential energy per unit charge; electric pressure created by a power source, such as a battery

instrument for measuring electric potential in volts

quantity of three-dimensional space occupied by a liquid, solid, or gas

measure of the rate of energy transfer over a unit of time, with one watt equal to one joule (J) per second: W = J/s

disturbance in which energy is transferred from one location to another

distance traversed by a periodic, or cyclic, motion per unit time (in any direction)

length of a wave from one peak to the next; measured from peak to trough

the force acting on an object due to gravity

force causing the movement—or displacement—of an object