Science Vocabulary from Glossary
absolute magnitude- the actual brightness of a star
acceleration- (ak sel uhr AY shuhn) the rate at which velocity changes; an object accelerates if its speed changes, if its direction changes, or if both its speed and its directions change
acid- any compound that increases the number of hydrogen ions when dissolved in water and whose solution tastes sour and can change the color of certain compounds; acids turn blue litmus red, react with metals to produce hydrogen gas, and react with limestone or baking soda to produce carbon dioxide gas
activation energy- the minimum amount of energy needed for substances to react
alkali metals- the elements in Group 1 of the periodic table; they are the most reactive metals, and their atoms have one electron in their outer level
alkaline earth metals- the elements in Group 2 of the periodic table; they are reactive metals but less reactive than alkali metals; their atoms have two electrons in their outer level
alloys- solid solutions of metals or nonmetals dissolved in metals
amplitude- the maximum distance a wave vibrates from its rest position
annular (AN yoo luhr) eclipse- a solar eclipse during which the outer ring of the sun can be seen around the moon
aphelion (uh FEE lee uhn) – the point in the orbit of a planet at which the planet is farthest from the sun
apparent magnitude – how bright a light appears to an observer
Archimedes’ (ahr kuh MEE deez) principle- the principle that states that the buoyant force on an object in a fluid is an upward force equal to the weight of the volume of fluid that the object displaces
area- a measure of how much surface an object has
asteroid- a small, rocky body that revolves around the sun
asteroid belt- the region of the solar system most asteroids occupy; roughly between the orbits of Mars and Jupiter
astronomical unit (AU) – the average distance between the Earth and the sun, or approximately 150,000,000 km
atmospheric pressure- the pressure caused by the weight of the atmosphere
atom- the smallest particle into which an element can be divided and still retain all of the properties of that element
atomic mass- the weighted average of the masses of all the naturally occurring isotopes of an element
atomic mass unit (amu) the SI unit used to express the masses of particles in atoms
atomic number- the number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element
average speed- the overall rate at which an object moves; can be calculated by dividing total distance by total time
balanced forces- forces on an object that cause the net force to be zero; balanced forces do not cause a change in motion or acceleration
base- any compound that increases the number of hydroxide ions when dissolved in water and whose solution tastes bitter, feels slippery, and can change the color of certain compounds; bases turn red litmus blue
battery- a device that is made of several cells and that produces an electric current by converting chemical energy into electrical energy
Bernoullli’s (buhr NOO leez) principle- the principle that states that as the speed of a moving fluid increases, its pressure decreases
big bang theory- the theory that states the universe began with a tremendous explosion
biochemicals- organic compounds made by living things
biomass- organic matter, such as plants, wood, and waste, that contains stored energy
black hole- an object with more than three solar masses squeezed into a ball only 10km across whose gravity is so strong that not even light can escape
block and tackle- a fixed pulley and a movable pulley used together; it can have a large mechanical advantage if several pulleys are used
boiling- vaporization that occurs throughout a liquid
boiling point – the temperature at which a liquid boils and becomes a gas
Boyle’s law- the law that states that for a fixed amount of gas at a constant temperature, the volume of gas increases as its pressure decreases
buoyant force- the upward force that fluids exert on all matter; buoyant force opposes gravitational force
carbohydrates- biochemicals composed of one or more simple sugars bonded together that are used as a source of energy and for energy storage
catalyst (KAT uh list)- a substance that speeds up a reaction without being permanently changed
cell- a device that produces an electric current by converting chemical energy into electrical energy
centripetal (sen TRIP uht uhl) acceleration the acceleration that occurs in circular motion; an object traveling in a circle is constantly changing directions, so acceleration occurs continuously
change of state- the conversion of a substance from one physical form to another
characteristic property- a property of a substance that is always the same whether the sample observed is large or small
Charles’s law – the law that states that for a fixed amount of gas at a constant pressure, the volume of gas increases as its temperature increases
chemical bond- a force of attraction that holds two atoms together
chemical bonding- the joining of atoms to form new substances
chemical change- a change that occurs when one or more substances are changed into entirely new substances with different properties; cannot be reversed using physical means
chemical energy- the energy of a compound that changes when its atoms are rearranged to form a new compound; chemical energy is a form of potential energy
chemical equation- a shorthand description of a chemical reaction using chemical formulas and symbols
chemical formula- a shorthand notation for a compound of a diatomic element using chemical symbols and numbers
chemical property- a property of matter that describes a substance based on its ability to change into a new substance with different properties
chemical reaction- the process by which one or more substances undergo change to produce one or more different substances
chromosphere (KROH muh sfir) a thin region of the sun’s atmosphere between the corona and the photosphere, too thin to see unless there is a total solar eclipse
circuit- a complete, closed path through which electric charges flow
closed system- a well defined group of objects that transfer energy between one another; energy is always conserved within a closed system
coefficient (KOH uh FISH uhnt)- a number placed in front of a chemical symbol or formula; used to balance a chemical equation
colloid( KAWL oyd) – a mixture in which the particles are dispersed throughout but are not heavy enough to settle out
comet- a small body of ice and rock that gives off gas and dust in the form of a tail as it passes close to the sun
compound- a pure substance composes of two or more elements that are chemically combined
compound machines- machines that are made of two or more simple machines
concentration- a measure of the amount of solute dissolved in a solvent
condensation- the change of state from a gas to a liquid
condensation point- the temperature at which a gas becomes a liquid
conduction- a method of charging an object that occurs when electrons are transferred from one object to another by direct contact
conductor – a material in which charges can move easily
convective zone- a region of the sun where hot and cooler gases circulate in convection currents, bringing the sun’s energy to the surface
core- the center of the sun where the sun’s energy is produced; the central, spherical part of the Earth below the mantle
corona- the sun’s outer atmosphere, which can extend outward a distance equal to 10 -12 times the diameter of the sun
cosmic background radiation- radiation left over from the big bang that fills all of space
cosmology- the study of the origin and future of the universe
covalent (koh VAY luhnt) bond- the force of attraction between the nuclei of atoms and the electrons shared by the atoms
covalent compounds- compounds that are composed of elements that are covalently bonded; these compounds are composed of independent molecules, tend to have low melting and boiling points, do not usually dissolve in water, and form solutions that do not conduct an electric current when they do dissolve
crust- the thin, outermost layer of the Earth, or the uppermost part of the lithosphere
crystal lattice(LAT is) a repeating three-dimensional pattern of ions
current- a continuous flow of charge caused by the motion of electrons; specifically, the rate at which charge passes a given point; expressed in amperes
data- any pieces of information acquired through experimentation
decomposition reaction- a reaction in which a single compound breaks down to form two or more simpler substances
density – the amount of matter in a given space; mass per unit volume
diffraction- the bending of waves around a barrier or through an opening
dimension- a measurement in one direction
double –replacement reaction- a reaction in which ions in two compounds switch places; one of the products is often gas or a precipitate
drag- the force that opposes or restricts motion through a fluid; drag opposes thrust
ductility (duhk TIL uh tee) -the ability of a substance to be drawn or pulled in a wire
eclipse- an event in which the shadow of one celestial body falls on another
electric discharge- the loss of static electricity as charges move off an object
electric force- the force between charged objects
electric generator- a device that changes kinetic energy into electrical energy
electric power- the rate at which electrical energy is used to do work; expressed in watts
electrical energy- the energy of moving electrons
electron clouds- the regions inside an atom where electrons are likely to be found
electrons- the negatively charged particle s found in all atoms; electrons are involved in the formation of chemical bonds
element- a pure substance that cannot be separated or broken down into simpler substances by physical or chemical means
ellipse- a closed curve in which the sum of the distances from the edge of the curve to two points inside the ellipse is always the same
elliptical galaxy- a spherical or elongated galaxy with a bright center and very little dust and gas
endothermic- the term used to describe a change in which energy is absorbed; the change can be a physical change or a chemical change
energy- the ability to do work
energy conversion- a change from one form of energy into anther; any form of energy can be converted into any other form of energy
energy efficiency (e FISH uhn see) – a comparison of the amount of energy before a conversion and the amount of useful energy after a conversion
energy resource- a natural resource that can be converted by humans into other forms of energy in order to do useful work
evaporation (ee vap uh RAY shuhn) vaporization that occurs at the surface of a liquid below its boiling point
exothermic- the term used to describe a change in which energy is released or removed; the change can be physical change or chemical change
fixed pulley- a pulley that is attached to something that does not move; fixed pulleys change the direction of the force but do not increase the force
fluid- any material that can flow and that takes the shape of its container
force- a push of a pull; all forces have both size and direction
fossil fuels- nonrenewable energy resources that form in the Earth’s crust over millions of years from the buried remains of once-living organisms
free fall- the condition an object is in when gravity is the only force acting on it
freezing- the change of state from a liquid to a solid
freezing point- the temperature at which a liquid changes into a solid
frequency- the number of waves produced in a given amount of time
friction- a force that opposes motion between two surfaces that are touching
fulcrum- the fixed point about which a lever pivots
galaxy- a large grouping of stars in space
gas- the state in which matter changes in both shape and volume
gas giants- the large, gaseous planets of the outer solar system
geothermal energy- energy resulting from the heating of the Earth’s crust
globular cluster- a group of older stars that looks like a ball of stars
gravitational potential energy- energy due to an object’s position above the Earth’s surface
gravity- a force of attraction between objects that is due to their masses
greenhouse effect- the natural heating process of a planet, such as the Earth, by which gases in the atmosphere trap thermal energy
group- a column of elements on the periodic table
H-R diagram- Hertzsprung-Russell diagram; a graph that shows the relationship between a star’s surface temperature and its absolute magnitude
halogens- the elements in Group 17 of the periodic table; they are very reactive nonmetals, and their atoms have seven electrons in their outer level
heterogeneous( het uhr oh JEE nee uhs) mixture- a combination of substances in which different components are easily observed
homogeneous(Hoh moh JEE nee uhs) mixture- a combination of substances in which the appearance and properties are the same throughout
hydraulic device (hie DRAW lik) – a device that uses liquids to transmit pressure from one point to another
hydrocarbons- organic compounds that are composed of only carbon and hydrogen
hydroelectricity- electrical energy produced from falling water
hypothesis- a possible explanation or answer to a question
ideal machine – a 100 percent efficient machine
inclined plane- a simple machine that is a straight, slanted surface; a ramp
induction- a method of charging an object that occurs when charges in a uncharged object are rearranged without direct contact with a charged object
inertia- the tendency of all objects to resist any change in motion
inhibitor- a substance that slows down or stops a chemical reaction
input force- the force applied to a machine
insulator- a material in which charges cannot easily move
interference- the result of two or more waves overlapping
ionic ( ie AHN ik) bond- the force of attraction between oppositely charged ions
ionic compounds- compounds that contain ionic bonds; composed of ions arranged in a crystal lattice, they tend to have high melting and boiling points, are solid at room temperature, and dissolve in water to form solutions that conduct an electric current
ions- charged particles that form during chemical changes when one or more valence electrons transfer from one atom to another
irregular galaxy- a galaxy that does not fit into any other category; one with an irregular shape
isotopes- atoms that have the same number of protons but have different numbers of neutrons
joule- the unit used to express work and energy; equivalent to the newton- meter (N m)
kinetic (ki NET ik) energy- energy of motion; kinetic energy depends on speed and mass
Kuiper (KIE puhr) belt- the region of the solar system outside the orbit of Neptune that is occupied by small, icy cometlike bodies
law- a summary of many experimental results and observations; a law tells you how things work
law of conservation of energy- the law that states that energy is neither created nor destroyed
law of conservation of mass- the law that states that mass is neither created nor destroyed in ordinary chemical and physical changes
law of electric charges- the law that states that like charges repel and opposite charges attract
law of universal gravitation- the law that states that all objects in the universe attract each other through gravitational force; the size of the force depends on the masses of the objects and distance between them
lever- a simple machine consisting of a bar that pivots at a fixed point, called fulcrum; there are three classes of levers, based on where the input force, output force, and fulcrum are placed in relation to the load: first class levers, second class levers, and third class levers
lift- an upward force on an object (such as a wing) caused by differences in pressure above and below the object; lift opposes the downward pull of gravity
light energy- the energy produced by the vibrations of electrically charged particles
light-minute- a unit of length equal to the distance light travels in space in one minute, or 18,000,000 km
light year- a unit of length equal to the distance that light travels in space in one year
lipids- biochemicals that do not dissolve in water; their functions include storing energy and making up cell membranes; lipids include waxes, fats, and oils
liquid- the state in which matter takes the shape of its container but has definite volume
load- a device that uses electrical energy to do work
longitudinal wave- a wave in which the particles of the medium vibrate back and forth along the path that the wave travels
lubricant (LOO bir kuhnt)- a substance applied to surfaces to reduce the friction between them
lunar eclipse- an event in which the shadow of the Earth falls on the moon’s surface
machine- a device that helps make work easier by changing the size or direction(or both) of a force
main sequence- a diagonal pattern of stars on the H-R diagram
malleability(Mal ee uh BIL uh tee) the ability of a substance to be pounded into thin sheets
mantle- the layer of the Earth between the crust and the core
mass- the amount of matter that something is made of; its value does not change with the object’s location in the universe
mass number- the sum of the protons and neutrons in an atom
matter- anything that has volume and mass
mechanical advantage- a number that tells how many times a machine multiplies force; can be calculated by dividing the output force by the input force
mechanical efficiency (e FISH uhn see) – a comparison expressed as a percentage of a machine’s work output with the work input; can be calculated by dividing work output by work input and then multiplying by 100
mechanical energy- the total energy of motion and position of an object
medium- a substance through which a wave can travel
melting- the change of state from a solid to a liquid
melting point- the temperature at which a substance changes from a solid to a liquid
meniscus (muh NIS kuhs) the curve at a liquid’s surface by which you measure the volume of the liquid
metallic bond- the attraction between a positively charged metal ion and the electrons in a metal
metalloids- elements that have properties of both metals and nonmetals; sometimes referred to as semiconductors
metals- elements that are shiny and are good conductors of thermal energy and electric current; most metals are malleable and ductile
meteor- a streak of light caused when a meteoroid or comet dust burns up in the Earth’s atmosphere before it reaches the ground
meteoroid- a very small, rocky body that revolves around the sun
meter- the basic unit of length in the SI system
mixture- a combination of two or more substances that are not chemically combined
model- a representation of an object or system
molecule( MAHL I Kyool)- a neutral group of atoms held together by covalent bonds
momentum- the property of a moving object that depends on the objects mass and velocity
moon- a natural satellite of a planet
motion- an object’s change in position over time when compared with a reference point
movable pulley- a pulley attached to the object being moved; movable pulleys increase force
nebula( NEB yuh luh)- a large cloud of dust and gas in interstellar space; the location of star formation
negative acceleration- acceleration in which velocity decreases; also called deceleration
net force- the force that results from combining all the forces exerted on an object
neutron star- a star in which all the particles have become neutrons; pressed- in remains of a supernova
neutrons- the particles of the nucleus that have no charge
newton(N) – the SI unit of force
noble gases- the unreactive elements in Group 18 of the periodic table; their atoms have eight electrons in their outer level (except for helium, which has two electrons)
nonmetals – elements that are dull (not shiny) and that are poor conductors of thermal energy and electric current
nonrenewable resource- a natural resource that cannot be replaced or that can be replaced only over thousands or millions of years
nuclear( NOO klee uhr) energy- the form of energy associated with changes in the nucleus of an atom; an alternative energy resource
nuclear fission – the process in which a large nucleus splits into two smaller nuclei
nuclear fusion- the process by which two or more nuclei with small masses join together, or fuse, to form a larger, more massive nucleus, along with the production of energy
nucleic acids- biochemicals that store information and help to build proteins and other nucleic acids; made up of subunits called nucleotides
nucleus (NOO klee uhs)- the tiny, extremely dense, positively charged region in the center of an atom; made up of protons and neutrons
observation- any use of the senses to gather information
Oort (ohrt)cloud- a spherical region of space that surrounds the solar system in which distant comets revolve around the sun
open cluster- a group of stars that forms when large amounts of gas and dust come together
orbit- the elliptical path a body takes as it travels around another body in space; the motion itself
organic compounds- covalent compounds composed of carbon-based molecules
output force- the force applied by a machine
parallax- an apparent shift in the position of an object when viewed from different positions
parallel circuit- a circuit in which different loads are on separate branches
pascal- the SI unit of pressure; equal to the force of one newton exerted over an area of one square meter
Pascal’s principle- the principle that states that a change in pressure at any point of an enclosed fluid is transmitted equally to all parts of that fluid
perihelion( PER I HEE lee uhn)- the point in the orbit of a planet at which the planet is closest to the sun
period – a horizontal row of elements on the periodic table
period of revolution- the time it takes for one body to make one complete orbit, or revolution, around another body in space
period of rotation- the time it takes for a body to rotate once as it spins about its axis
periodic- having a regular, repeating pattern
periodic law- a law that states that the chemical and physical properties of elements area periodic functions of their atomic numbers
perpetual (puhr PECH oo uhl) motion machine- a machine that runs forever without any additional energy input; a machine whose energy output would equal its energy input; perpetual motion machines are impossible to create
pH- a measure of hydronium ion concentration in a solution; a pH of 7 is neutral; a pH than 7 is acidic; a pH greater than 7 is basic
phases- the different appearances of the moon due to varying amounts of sunlight on the side of the moon that faces the Earth; results from the changing relative positions of the moon, Earth , and sun
photocell- the part of a solar panel that converts light into electrical energy
photosphere- the layer of the sun at which point the gases get thick enough to see; the surface of the sun
physical change- a change that affects one or more physical properties of a substance; most physical changes are easy to undo
physical property- a property of matter that can be observed or measured without changing the identity of the matter
physical science- the study of matter and energy
planetesimal (Plan i TES I muhl)- the tiny building blocks of the planets that formed as dust particles stuck together and grew in size
plasma- the state of matter that does not have a definite shape or volume and whose particles have broken apart; plasma is composed of electrons and positively charge ions
positive acceleration- acceleration in which velocity increases
positive difference- energy per unit charge; specifically, the difference in energy per unit charge as a charge moves between two points in an electric circuit(same as voltage); expressed in volts
potential energy- energy of position of shape
power- the rate at which work is done
pressure- the amount of force exerted on a given area; the SI unit for pressure is the pascal
products- the substances formed from a chemical reaction
prograde rotaion – the counterclockwise spin of a planet or moon as seen from above the planet’s north pole
projectile (proh JEK tuhl) motion- the curved path an object follows when thrown or propelled near the surface of Earth
proteins – biochemicals that are composed of amino acids; their functions include regulating chemical activities, transporting and storing materials, and providing structural support
protons- the positively charged particles of the nucleus; the number of protons in a nucleus is the atomic number, which determines the identity of an element
pulley- a simple machine consisting of a grooved wheel that holds a rope or a cable; there are two kinds of pulleys – fixed and movable
pulsar- a spinning neutron star that emits rapid pulses of light
pure substance- a substance in which there is only one type of particle; includes elements and compounds
quasar- a “ quasi-stellar” object; a starlike source of light and radio waves that is extremely far away; one of the most powerful sources of energy in the universe
radiative zone- a very dense region of the sun in which the atoms are so closely packed that light takes a long time to travel through
reactants (ree AKT uhnt) -the starting materials in a chemical reaction
red giant- a star that expands and cools once it runs out of hydrogen fuel
reference point- an object that appears to stay in place in relation to an object being observed for motion
reflection- the bouncing back of a wave after it strikes a barrier or object
refraction- the bending of a wave as it passes at an angle from one medium to another
renewable resource- a natural resource that can be used and replaced over a relatively short time
resistance- the opposition to the flow of electric charge; expressed in ohms
resonance- what occurs when an object vibrating at or near the resonant frequency of a second object causes the second object to vibrate
resultant velocity- the combination of two or more velocities
retrograde orbit- the clockwise revolution of a satellite around a planet as seen from above the north pole of the planet
retrograde rotation- the clockwise spin of a planet or moon as seen from above the planet’s or moon’s north pole
revolution- the elliptical motion of a body as it orbits another body in space
rotation- the spinning motion of a body on its axis
salt- an ionic compound formed from the positive ion of a base and the negative ion of an acid
satellite- a natural or artificial body that revolves around a planet
saturated hydrocarbon- a hydrocarbon in which each carbon atom in the molecule shares a pair of electrons with each of four other atoms
saturated solution- a solution that contains all the solute it can hold at a given temperature
scientific method- a series of steps that scientists use to answer questions and solve problems
screw- a simple machine that is an inclined plane wrapped in a spiral
series circuit- a circuit in which all parts are connected in a single loop
simple machines- the six machines from which all other machines are constructed: a lever, an inclined plane, a wedge, a screw, a wheel and axle, and a pulley
single-replacement reaction- a reaction in which an element takes the place of an element in a compound; this can occur only when a more-reactive element takes the place of a less-reactive one
solar eclipse- an event in which the shadow of the moon falls on the Earth’s surface
solar nebula- the nebula that formed into the solar system
solar system- the system composed of the sun( a star) and the planets and other bodies that travel around the sun
solid- the state in which matter has a definite shape and volume
solubility (sahl yoo BIL uh tee)- the ability to dissolve in another substance; more specifically the amount of solute needed to make a saturated solution using a given amount of solvent at a certain temperature
solute- the substance that is dissolved to form a solution
solution- a mixture that appears to be a single substance but is composed of particles of two or more substances that are distributed evenly amongst each other
solvent- the substance in which a solute is dissolved to form a solution
sound energy- the energy caused by an object’s vibrations
spectrum- the rainbow of colors produced when white light passes through a prism or spectrograph
speed- the rate at which an object moves; speed depends on the distance traveled and the time taken to travel that distance
spiral galaxy- a galaxy with a nuclear bulge in the center and very distinctive spiral arms
standing wave- a wave that forms a stationary pattern in which portions of the wave do not move and other portions move with a large amplitude
states of matter- the physical forms in which a substance can exist; states include solid, liquid, gas and plasma
static electricity- the buildup of electric charges on an object
sublimation (suhb luh MAY shuhn) the change of state from a solid directly into a gas
subscript- a number written below and to the right of a chemical symbol in a formula
sunspot- an area on the photosphere of the sun that is cooler than surrounding areas, showing up as a dark spot
supernova- the death of a large star by explosion
surface gravity- the percentage of your Earth weight you would experience on another planet; the weight you would experience on another planet
surface tension- the force acting on the particles at the surface of a liquid that causes the liquid to form spherical drops
surface wave- a wave that occurs at or near the boundary of two media and that is a combination of transverse and longitudinal waves
suspension- a mixture in which particles of a material are dispersed throughout a liquid or gas but are large enough that they settle out
synthesis (SIN thuh sis) reaction- a reaction in which two or more substances combine to form a single compound
technology- the application of knowledge, tools, and materials to solve problems and accomplish tasks; technology can also refer to the objects used to accomplish tasks
temperature- a measure of how hot (or cold) something is; specifically, a measure of the average kinetic energy of the particles in an object
terminal velocity- the constant velocity at which a falling object travels when the size of the upward force of air resistance matches the size of the downward force of gravity
terrestrial planets- the small, dense, rocky planets of the inner solar system
theory- a unifying explanation for a broad range of hypotheses and observations that have been supported by testing
thermal energy – total kinetic energy of the particles that make up an object
thermocouple- a device that converts thermal energy into electrical energy
thrust- the forward force produced by an airplane’s engines; thrust opposes drag
transverse wave- a wave in which the particles of the wave’s medium vibrate perpendicular to the direction the wave is traveling
turbulence- an irregular or unpredictable flow of fluids that can cause drag; lift is often reduced by turbulence
unbalanced forces- forces on an object that cause the net force to be other than zero; unbalanced forces produce a change in motion or acceleration
unsaturated hydrocarbon- a hydrocarbon in which not all carbon atoms have four single bonds; at least one double or triple bond is present
valence (VAY luhns) electrons- the electrons in the outermost energy level of an atom; these electrons are involved in forming chemical bonds
vaporization- the change of state from a liquid to a gas; includes boiling and evaporation
velocity( vuh LAHS uh tee)- the speed of an object in a particular direction
viscosity( vis KAHS uh tee)- a liquids resistance to flow
voltage- the difference in energy per unit charge as a charge moves between two points in an electric circuit (same as potential difference); expressed in volts
volume- the amount of space that something occupies or the amount of space the something contains
watt- the unit used to express power; equivalent to joules per second (J/s)
wave- a disturbance that transmits energy through matter or space
wave speed- the speed at which a wave travels
wavelength- the distance between one point on a wave and the corresponding point on an adjacent wave in a series of waves; for example, the distance between two adjacent crests or compressions
wedge- a simple machine that is a double inclined plane that moves; a wedge is often used for cutting
weight- a measure of the gravitational force exerted on an object, usually by the Earth
wheel and axle- a simple machine consisting of two circular objects of different sizes; the wheel is the larger of the two circular objects
white dwarf- a small, hot star near the end of its life; the leftover center of an old star
work- the action that results when a force causes an object to move in the direction of the force
work input- the work done on a machine; the product of the input force and the distance through which it is exerted
work output- the work done by a machine; the product of the output force and the distance through which it is exerted.
Last Update: 04/27/2010 05:48 PM -0500