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PHYSICAL SCIENCE VOCABULARY

acceleration- The rate of change in atomic nucleus; has a charge of 2+, an velocity (a change in direction or a atomic mass of 4, and is the largest, change in speed). slowest, and least penetrating form of acid- A substance that produces . ions in solution; these amalgam- An alloy containing the solutions have a pH less than 7. element mercury; an example is dental (AC) - Electric fillings. current that reverses its direction in a ammeter- A that regular pattern; the 60-Hz AC in our measures electrical current passing homes changes direction 120 times each through in ; connected in a second. series with the circuit. acid rain - Rain with a pH less than 5.6; amorphous- Something that has no produced by substances in the air specific shape; for example, a liquid or reacting with rainwater. gas. acoustics -The study of sound. -The unit of measuring current, actinide- Any of the 14 radioactive the rate of flow of electrons in a circuit. elements having atomic numbers 90- amplification- The process of increasing 103; used in nuclear power generation the strength of an electric signal. and nuclear weapons. amplitude- In a wave, the distance from active solar heating - Collecting the the rest position of the medium to either sun's with solar panels, heating the crest or trough. water with that energy, and storing the amplitude modulated - (AM) waves - heated water to use the energy later. Radio waves whose amplitude is varied aerosol -A liquid sprayed from a with voice, music, video, or data for pressurized container; for example, a can transmission over long distances. of insect spray. angle of incidence - In waves, the angle air resistance - Frictional air formed by the incident wave and the exerts on a moving object; acts opposite normal. in direction to the object's motion. angle of reflection - In waves, the angle alchemist -A medieval version of the formed by the reflected wave and the modern chemist; a practitioner who normal (perpendicular). blended primitive chemistry with magic, anhydrous- A chemical compound that seeking to turn ordinary metals into normally has water attached gold. to its ions but from which water has been alcohol -Type of compound formed removed. when -OH groups replace one or more antacid -An "anti-acid," or a chemical hydrogen in a hydrocarbon. that changes an acid substance to a allotropes -Different structural forms of neutral substance. the same element; for example, some antifreeze -A solute added to a solvent carbon molecules form soft graphite, to lower the temperature at which the whereas others form hard diamonds. solvent will freeze. alloy -A mixture consisting of a metal aqueous -Describes a solution made and one or more elements. with water. alpha particle - A particle of nuclear radiation emitted from a decaying PHYSICAL SCIENCE VOCABULARY

Archimedes' principle - This Greek particle - A negatively charged mathematician stated that the buoyant electron or positively charged positron force on an object in a fluid is equal to emitted from a decaying atomic nucleus. the weight of the fluid displaced by the binary compound - A chemical object. compound composed of two elements; aromatic compounds - Chemical for example, sodium chloride. compounds that contain the benzene ring biogas Mixture of gases, mostly structure; most have distinctive odors. , produced when biomass is artificial satellite - Human-made device allowed to rot in the absence of air. that orbits Earth; used for biomass -Organic material from such , weather-monitoring, sources as wood, corn, and wastes from military, and scientific purposes. animals and crops. atomic number - The number of bionics The science of designing protons in an 's nucleus. artificial replacements for parts of the average speed - A rate of motion human body that are not working determined by dividing the total distance properly. traveled by the total travel time. boiling point - The average atomic mass - The average temperature at which vapor mass of the mixture of an element's bubbles form in a liquid and isotopes. rise to the surface, balance -A device used in laboratories increasing evaporation. to measure mass; it works by balancing a Boyle's law - British mass to be determined with a standard scientist Robert Boyle mass that is known. stated that volume of a gas decreases balanced chemical equation - A when the pressure increases, provided chemical equation that has the same the temperature stays the same. number of atoms of each element on bubble chamber - Device filled with both sides of the equation. superheated liquid; used to detect and balanced - Forces that are equal monitor the path of charged nuclear in size and opposite in direction. particles, which leave a trail of bubbles bar graph - A type of graph used to as they pass though the chamber. show information collected buoyant force - Ability of a fluid to by counting; uses vertical or exert an upward force on an object horizontal bars of different immersed in the fluid. lengths to help people butane -A flammable gas; part of compare quantities. natural gas. base -A substance that byte -A basic unit of computer memory produces hydroxide ions (OH-) in the represents a character (number, solution; these solutions have a pH symbol, or alphabet letter); consists of 8 over 7. bits. Bernoulli's principle - The Swiss calorimeter- An instrument used to scientist Daniel Bernoulli stated that as measure changes in thermal energy. the velocity of a fluid increases, the carbohydrate An organic compound pressure exerted by the fluid decreases. having twice as many hydrogen atoms as oxygen atoms. PHYSICAL SCIENCE VOCABULARY

carbon 14 dating - Age-determining which elements are in a compound and method for carbon-containing objects up their ratios. to 50,000 years old. chemical property - A characteristic of catalyst-A substance that speeds a a substance that indicates whether it can without itself being undergo a specific chemical change. permanently changed. chemical reaction - A change in which cathode ray tube (CRT) - Sealed glass one or more substances are converted to vacuum tube that uses electrons and different substances. fluorescent material to produce images chemical symbol - A shorthand way to on a screen. write the name of an element; for central processing unit - The main example: C for carbon, Ag for silver. circuit board inside a chemically stable - Describes an atom computer that performs the whose outer energy level is completely calculating and holds the filled with electrons. main memory. chemically unstable - Describes an centripetal acceleration - atom whose outer-most energy level is Acceleration toward the not filled with electrons so it seeks center of a circle by an object moving electrons from other atoms and thus along a circular path. forms compounds. centripetal force - The force that causes chloro Prefix that indicates presence of an object moving along a circular path to , as in tetrachloroethylene or move toward the center of the path. chlorofluorocarbon. ceramic A material made from dried CFC A group of compounds whose clay or claylike mixtures. decomposition releases chlorine atoms cermet A tough, heat-resistant material that destroy ozone molecules in the that has the properties of both a ceramic upper atmosphere. and an alloy; ceramic-metal. circuit A closed path through which chain reaction - A continuing series of electrons flow. fission reactions in which from - A device that protects fissioning nuclei cause other nuclei to an electrical circuit; if too much current split, releasing more neutrons, which flows, the device opens the circuit, split more nuclei, and so on. stopping the current. Charles's law - The volume of a gas cloud chamber - Device filled with increases when temperature increases, water- or ethanol-saturated air; used to provided the pressure stays the same. detect charged nuclear particles, which chemical bond - The force that holds leave a trail as they pass through. together the atoms in a compound; it coagulation Process that destroys occurs because atoms of most elements colloid structure; can be used to reduce a become more stable by losing, gaining, colloidal form of air pollution. and sharing electrons. coal A rock formed of ancient decayed chemical change - The plants; burned as a fossil . change of substances to coefficient In a chemical equation, the different substances. number that represents the number of chemical formula - A units of each substance taking part in a precise statement that tells chemical reaction. PHYSICAL SCIENCE VOCABULARY

coherent light - A beam of light in constant speed - Speed that does not which all the electromagnetic waves change. travel with the crests and troughs contraction Movement of molecules aligned; thus, the beam does not spread toward one another, so that they occupy out. a smaller space. colloid A heterogeneous mixture Rapid burning. containing tiny particles that never settle composite A mixture of two materials, out; for example, milk and gelatin. one of which is embedded in the other. compression In compressional waves, compound Substance made of the the dense area of the wave. combined atoms of two or more compressional wave - A type of wave elements. where matter vibrates in the same compound - A combination of direction the wave travels. two or more simple . computer A device you can program to constant In an experiment, a factor that do calculations, make logical decisions, does not change. and manipulate data. control In an experiment, a standard for computer virus - Type of program comparison that is often needed to draw designed to infect a computer, erase a meaningful conclusion. data, scramble other programs, or fill up convection The transfer of energy by the so much memory that the system is bulk movement of matter in which harmed. particles move from place to place in concave - Lenses that are thinner fluid, carrying the energy with them. in the middle and thicker at the edges convex lenses - Lenses that are thicker and thus curve inward; form virtual, in the middle than at the edges; can upright, smaller images of an object. produce both real and virtual images. concave - A mirror whose convex mirror - A mirror with a surface surface curves inward; produces real that curves outward; produces upright, images. smaller, virtual images of an object. concentrated solution - A solution in corrosive Hazardous compound that which the amount of solute is near the attacks and alters metals, human tissue, maximum the solvent can hold at that or other materials; for example, oven temperature. cleaners and battery acid. concentration Generally, the proportion coulomb The charge carried by 6.24 of a solute dissolved in a solvent. billion billion electrons. condensation The change of a substance covalent bond - A type of chemical from a gas to a liquid, which usually bond formed by atoms when they share takes place when a gas is cooled to or electrons. below its boiling point. crest The highest point of a wave. condense To go from the gas state to the critical temperature - In liquid state, due to a loss of heat. superconductors, the very low conduction The transfer of energy temperature at which a material ceases to through matter in which energy moves have any electrical resistance. from particle to particle. crystals In most solids, the arrangements conductor A material that allows of particles in repeating geometric electrons to move easily through it. patterns. PHYSICAL SCIENCE VOCABULARY

current The flow of electrons through a A type of that allows wire or any conductor; measured in to flow in only one amperes with an ammeter. direction. deceleration The rate of change in - Electrical current that velocity (speed and/or direction) when flows in only one direction through a velocity is decreasing; also called wire. negative acceleration. disinfectant A chemical that kills decibel The unit of measure for sound bacteria, such as alcohol. intensity, abbreviated dB. dissociation – The breaking apart of an decomposition reaction - A chemical ionic compound into positive and reaction in which a substance breaks negative ions when dissolved in water. down into two or more simpler doping Adding an impurity to a substances. semiconductor to increase its electrical dehydrating agent - A substance that conductivity. can remove water from materials. Doppler effect - An increase or decrease density The mass per unit volume of a in wave frequency, caused by motion of material; describes how tightly packed a the source and/or motion of the observer; substance's molecules are. applies to all waves. dependent variable - In an experiment, dot diagram - A diagram to represent the factor whose value changes because electrons in the outer energy level of an of a change in the independent variable. atom; uses the element symbols and derived - Unit of measurement obtained dots. by combining SI units. double displacement reaction - A detergent An organic salt similar to chemical reaction in which two ionic soap, except that detergents do not form compounds in solution react, forming a soap scum in hard water. precipitate, gas, or water. diatomic - A molecule dry cell - A power source that acts as an composed of two atoms of the same electron and generates electric element. current by a chemical reaction; uses diesel - An internal combustion thick, pasty electrolyte. engine that compresses a fuel-air ductile – ability of metals to be pulled mixture so much that it ignites from the into wires heat of compression without a spark. effort arm - The part of a on diffraction The bending of waves which an effort force is applied. around a barrier. effort force - The force applied to a diffraction grating - A piece of glass or machine when a machine is used to do with many parallel slits that acts . like a prism, causing white light that electric field - An area surrounding an passes through it to separate into its electron that exerts a force on anything component colors. nearby with an ; strongest dilute solution - A solution in which the nearest the electron and weakens with amount of solute is much less than the distance. maximum the solvent can hold at that - A device that contains a temperature. rotating electromagnet that changes electrical energy to mechanical energy. PHYSICAL SCIENCE VOCABULARY

electrical power - The rate at which evaporation The gradual change of a electrical energy is converted to another substance from a liquid to a gas at form of energy; electrical power is temperatures below the boiling point. expressed in watts or kilowatts. exothermic reaction - A chemical electrolyte A substance that separates or reaction in which energy is released. forms ions in a water solution, making Outward movement of molecules away the solution an electrical conductor. from one another so that they occupy a electromagnet Strong temporary larger space. made by inserting an core expansion combustion engine - An into a wire coil and passing an electric engine in which the fuel is burned current through the coil. outside the engine. electromagnetic induction - Process by experiment An organized procedure for which electrical current is induced in a testing a hypothesis; typically has a wire when it is moved through a control and dependent and independent . variables. electromagnetic radiation - Transverse farsighted Describes a person who sees waves that transfer energy by radiation; faraway things clearly, but has trouble vary in length from very long radio focusing on nearby objects. waves to extremely short gamma waves. fiberglass Hairlike strands of glass that electron arrangement - In an atom, make a good when arranged in how the electrons are distributed in the puffy layers. atom's various energy levels. filter In working with light, a device that electron cloud - Region where electrons allows one or more colors to be most probably are found surrounding the transmitted while others are absorbed or nucleus of an atom. blocked. electrons Negatively charged particles flammable A chemical characteristic of that move around the nucleus of an a substance that allows it to oxidize atom. rapidly. electroscope A device containing two fluid Any material that flows, such as suspended metal leaves in a jar that liquids and gases. move apart when charged; used to detect fluorescence Occurs when a material the presence of electric charges. absorbs ultraviolet radiation that element Substance in which all the stimulates it to radiate visible light. atoms in a sample are alike. fluorescent light - Light produced when endothermic reaction - A chemical ultraviolet radiation inside a fluorescent reaction in which energy is absorbed. light bulb causes its fluorescent coating energy The ability to cause change. to glow. energy farming - The growing of plants - The distance from the for use as fuel. center of a or mirror to its focal energy transfer - The movement of point. energy from one object to another; for focal point - A point on the optical axis example, thermal energy flowing as heat of a concave mirror or convex lens from a heated stove to a skillet. where the light rays come together. ester An organic compound formed by force A push or pull one body exerts on reacting an organic acid with an alcohol. another. PHYSICAL SCIENCE VOCABULARY

fractional distillation - A process based gasoline, but whose production may be on boiling points used in oil refineries to damaging to the environment; a biomass separate the chemical compounds in fuel. crude oil into gasoline, kerosene, and gear A wheel with teeth around its edge other products. designed to mesh with teeth on another fractionating towers - Towers at oil gear so as to transfer force and motion. refineries used for fractional distillation gelatin A substance obtained by boiling of petroleum. animal bones; used in glues and goods. free fall - How an object moves in space generator A device that uses when it is influenced only by gravity. electromagnetic induction to induce freon A refrigerant gas used in electrical current by rotating loops of refrigerators and air conditioners. wire through a magnetic field. frequency The number of wave crests geothermal energy - Thermal energy that pass a point during one second; source located far below Earth's crust. expressed in hertz. glass A ceramic mixture with no regular frequency modulated - Radio waves crystal structure. whose frequency is varied with voice, graduated cylinder - A cylinder marked music, video, or data for transmission with volume scale, used in laboratories over long distances. for measuring liquid volumes. The force that opposes motion graph A visual display of information or between two surfaces that are touching data organized to help people interpret, each other. understand, or quickly find information. fuel rod - A metal rod filled with graphite A mineral made of carbon uranium pellets, used as the fuel in a atoms arranged in layers that easily slide . past one another, forming a dry fulcrum The fixed point around which a lubricant. lever pivots. gravity Force exerted by every object in fuse A device that protects an electrical the universe on every other object. The circuit. amount of force depends on the masses galvanometer An instrument used to of the objects and the distance between detect electric currents. them. gamma rays - High frequency grounded Electrically connected to electromagnetic waves that travel at the Earth, either directly or through a wire or speed of light, have no mass or charge, other metal object. and are the most penetrating form of group In the periodic table, each of the radiation. 18 vertical columns of elements; each gamma rays - High frequency group is made up of elements with electromagnetic waves that travel at the similar properties. speed of light, have no mass or charge hacker A person who uses a computer and are the most penetrating form of to break into other computer systems radiation. without permission. gaseous solution - A homogeneous gas half life - The amount of time required that is composed of two or more gases. for one-half of the nuclides in a sample gasohol A mixture of ethanol and of radioactive isotope to decay. gasoline that is a useful substitute for PHYSICAL SCIENCE VOCABULARY

halogens Highly active elements in - A periodic table Group 17; they have seven consisting of a sloping surface used to electrons in their outer shells and readily raise objects. combine with Group 1 elements. incoherent light - Light rays that are heat Thermal energy that flows from a nearly parallel, but spread out because warmer material to a cooler material. their electromagnetic waves do not heat engine - A device that converts travel in the same direction. thermal energy that is produced by ideal machine - A machine in which burning fuel into mechanical energy. work input equals work output; such a heat mover - A device that moves perfect machine would be frictionless thermal energy from one location and and 100 percent efficient releases it in another location having a independent variable - In an different temperature. experiment, the factor adjusted to a heat of fusion - The amount of energy different value by the experimenter to needed to change a material from the see what effect it will have on the solid state to the liquid state. dependent variable. heat of vaporization - The amount of indicator An organic compound that energy needed to change a material from changes color in an acidic solution or a a liquid to a gas. basic solution. herbicide A chemical poison that kills induction Electrically charging an undesirable plants. object or creating an electrical current in hertz The unit of measure for frequency. it, without physically touching it. heterogeneous mixture - A mixture in inertia The tendency of an object to which different parts can be easily resist any change in its motion. If distinguished. motionless, it tends to remain at rest; if homogeneous mixture – A mixture in moving, it tends to keep moving at the which different materials are blended same speed and in the same direction. evenly so that the mixture is the same infrared radiation - Electromagnetic throughout; also called a solution. waves that have a wavelength slightly hydrate A compound that has water longer than visible light; indicates the molecules chemically attached to its ions presence of heat. and written into its formula. infrasonic waves - Waves at frequencies hydraulic Describes a system operated below the limit of human hearing. by the energy of moving water. inhibitor A substance that slows or hydrocarbon A compound containing prohibits a chemical reaction. only carbon and hydrogen atoms. instantaneous speed - The rate of hydronium ion - The ion that makes a motion at a given instant in time. solution acidic. insulator A material that does not allow hypothesis A testable prediction used to heat or electrons to move through it see how something works or to solve a easily. problem. - A thin slice of incandescent light - Light produced by silicon, often less than 1 cm on a side, a thin tungsten wire, or filament, that is which can contain thousands of resistors, heated in an incandescent bulb until it , and transistors; used in computer glows. and electronic equipment. PHYSICAL SCIENCE VOCABULARY

intensity In sound waves, the amount of Law of conservation of mass - A law energy in each wave. stating that matter is neither created nor interference The ability of two or more destroyed during a chemical change. waves to combine to form a new wave. Law of conservation of momentum - A internal combustion engine - An law stating that the total momentum of a engine in which fuel is burned inside the group of objects is conserved unless a engine in chambers. net force acts on the objects. ion A positively or negatively charge lever A simple machine consisting of a atom. bar that is free to pivot around a fixed ionic bond - A type of chemical bond point. formed by the attraction between line graph - A type of graph used to opposite charges of the ions in an ionic show trends or continuous change by compound. drawing a line that connects data points. ionization The breaking apart of certain lipids Fats, oils, and related organic polar substances to form ions when compounds. dissolved in water. liquid solution - A liquid solvent that isomers Compounds that have identical has dissolved in it a gas, liquid, or solid. chemical formulas but different liter The unit of liquid volume that molecular structures and shapes. occupies the same volume as a cubic isotopes Atoms of the same element that decimeter and is slightly larger than a have different numbers of neutrons. quart. joule The basic unit of energy and work. loudness The human perception of kelvin The SI unit of temperature. sound intensity. kilogram The SI unit of mass. lubricant A substance used to reduce kilowatt hour - The unit of electrical friction between two surfaces that move energy. together; for example, oil, kinetic energy - Energy in the form of grease, or graphite. motion, as in a moving car or truck. machine A device that kinetic theory of matter - The idea that makes work easier by all matter is made up of constantly changing the size of the moving, tiny particles. force applied to it and/or the direction of lanthanide Any of the 14 metallic the force. elements having atomic numbers 58-71; magnetic bottle - A powerful magnetic used in , ceramics, and field that creates a container to hold the television picture tubes. hydrogen plasma needed for a nuclear laser A device that emits a beam of fusion reaction. that travel in the same direction magnetic domains - Groups of atoms and phase, producing a beam of coherent with aligned magnetic poles. light. magnetic field - The region around a Law of conservation of energy - A law magnet where magnetic forces act. stating that energy can change form but magnetic poles - The two ends of a cannot be created or destroyed under piece of magnetic material where the ordinary conditions. magnetic forces are strongest, labeled north pole and south pole. PHYSICAL SCIENCE VOCABULARY

A property of some A optical materials in which there is a force of instrument that uses two repulsion or attraction between certain convex lenses with like and unlike poles. relatively short focal magnifier A device that lengths to magnify small, makes things appear larger so close-up objects. that more detail can be seen; microwaves Radio waves with the for example, a microscope. highest frequency and energy; used in malleable Ability of metals to be and microwave ovens. hammered or rolled into thin sheets. mixture A material made of elements or mass A measurement of the amount of compounds stirred together but not matter in an object. combined chemically. mass number - Sum of the number of model A symbolic representation of an protons and neutrons in an atom's idea, system, or structure to make nucleus. something understandable. - The number of modulation Process of adding voice, times a machine multiples the effort music, video, computer information, or force applied to it. other data to radio waves by using mechanical energy - The total amount electrical currents to vary either of kinetic energy and potential energy in amplitude or frequency. a system. momentum A property of any moving medium A material through which a object; the product of an object's mass wave travels. and velocity. melt The changing of a substance from a monomers Organic molecules that are solid state to a liquid state when heated strung together to form . above the substance's freezing/melting music Sound created using specific point. pitches, sound quality, and regular melting point - The temperature at patterns. which a solid changes to a liquid. nearsighted Describes a person who metallic bonding - The type of chemical sees nearby things clearly, but has bond in which positively charged ions trouble focusing on distant objects. are surrounded by freely moving net force - The sum of the forces on an electrons. object when unbalanced forces are metalloids Elements having properties applied to it. of both metals and nonmetals. neutralization A chemical reaction metals Elements usually having these between an acid and a base. common properties: shiny, good neutralize To change an acidic solution conductors of heat and , are or a basic solution so that it is neutral. solids at room temperature. Atomic particle with no charge meter The SI base unit of length. that is part of an atom's nucleus. microprocessor The computer's "brain." Newton's first law of motion - It receives input and tells the computer Describes the relationship between how to respond. velocity and forces. An object moving at a constant velocity keeps moving at that velocity unless a net force acts on it. PHYSICAL SCIENCE VOCABULARY

Newton's second law of motion - medicine, and so on; storing it is a Describes the acceleration of an object in political and environmental problem. the direction of the net force applied to nucleic acid - An organic that it. controls the activities and reproduction Newton's third law of motion - of cells. Describes action-reaction pairs; for nucleus The positively charged center of every action force, there is an equal and an atom that contains protons and opposite reaction force. neutrons. NIMBY Not in my backyard; a point of nuclide The nucleus of a specific isotope view that supports an issue such as having a certain specific atomic number nuclear generation of electricity as long and atomic mass. as it does not take place close to home. observation Using your senses to gather noise Sound that has no regular pattern information. or definite pitch. ocean thermal energy conversion - nonelectrolyte A substance, such as Process that uses heat to convert pure water, that does not conduct differences in ocean temperatures into electricity. mechanical energy to drive turbines. nonmetals Elements that usually are ohm The unit for measuring resistance. gases or brittle solids at room Ohm's law - States that potential temperature; most do not conduct heat or difference equals current multiplied by electricity well. resistance. nonpolar molecule - A molecule that opaque materials - Materials you can't does not have oppositely charged ends. see through because they absorb or nonrenewable resources - Resources reflect all light. such as coal, oil, and natural gas, which Optical axis - A line perpendicular to cannot be replaced after they are used the center of a mirror or lens. up. optical fiber - Transparent glass fiber normal In the study of light, an that can transmit light from one place to imaginary line drawn perpendicular to a another. reflecting surface or perpendicular to a organic compounds - Chemical medium that light is entering. compounds that contain the element - Process in which an carbon. atom's nucleus is split into two nuclei organic solvent - A type of liquid often with smaller masses. found in building materials; contains nuclear fusion - Process in which two potentially harmful chemicals. atomic nuclei with low masses are fused oxidation number - A positive or into a single nucleus of larger mass; also negative number that indicates how known as a thermonuclear reaction. many electrons an atom has lost, gained, nuclear reactor - A device that or shared when bonding with other generates electricity from a controlled atoms. nuclear fission chain reaction. parallel circuit - An electrical circuit nuclear waste - where the current flows through more Radioactive by-products than one path. If one path is interrupted, from nuclear power current will still flow through the other generation, nuclear paths. PHYSICAL SCIENCE VOCABULARY

pascal The SI unit of pressure. pitch The highness or lowness of a sound, Pascal's principle - French scientist Blaise which is determined by the frequency of the Pascal stated that pressure applied to fluid is sound waves. transmitted unchanged through the fluid. plane mirror - A mirror with a flat surface passive solar heating - Direct use of the that produces a virtual image. sun's energy to heat something, without plankton Tiny plants and animals that live using fans or mechanical devices to transfer in water and are food for small fish; they are heat from one area to another. easily killed by acid rain. period A horizontal row in the periodic plasma A gaslike mixture of charged table. particles that exists at extremely high periodic table - A table of the elements temperatures. arranged according to repeated changes in plastic polymer-based material that can be properties. easily molded. PET Scans that are used in medicine to polar molecule - A molecule with opposite reveal brain function and certain brain charges on each end. disorders such as tumors. polarized light - Light in which the petroleum Crude oil, formed by decayed transverse waves vibrate only along one remains of plants and animals; a fossil fuel plane. that is burned and used to make lubricants polarizing filter - A filter made of chains of and . molecules in parallel rows that will transmit pH A measure of hydronium ion only light waves vibrating in the same concentration in solution. direction as the molecular chains. phenolphthalein A chemical used as a color polluted water - Water that contains high indicator in titration; colorless in an acidic levels of unwanted substances that may be solution, but turns pink in a basic solution. harmful to living things. A tiny particlelike bundle of polyatomic ion - A group of covalently radiation. bonded atoms in which the whole group is photovoltaic cell - A device used to convert positively or negatively charged. solar energy directly into electrical energy; polymer A huge molecule made up of many also called a solar cell. smaller organic molecules, called physical change - A change in the size, monomers, that have formed new bonds and shape, color, or state of matter. are linked together. Physical property - Any characteristic of a positron A positively charged particle material that can be observed without similar to an electron. changing the identity of the material itself. potential difference - The difference in physical science - The study of matter and electric potential energy between two energy; topics for study include chemistry different points; measured in volts. and . potential energy - Stored energy. pickling A process that removes impurities power The measure of the amount of work from the surfaces of steel and other metals done in a specific amount of time. by dipping them in hydrochloric acid. precipitate An insoluble compound formed pigment Colored material that absorbs some during a double-displacement reaction. colors and reflects others; the colors of pressure The amount of force exerted per pigments are determined by the colors they unit of area. reflect. PHYSICAL SCIENCE VOCABULARY

principle A basic rule or law describing rectifier Any device that converts how something always works in the natural alternating current into direct current. world. reflecting telescope - An optical instrument products In a chemical reaction, the that uses a concave mirror, a plane mirror, substances produced by the reaction. and a convex lens to magnify distant objects. projectile Any object shot or thrown reflection Occurs when a wave strikes an through the air. object and bounces off. propane A flammable gas and a part of refracting telescope - An optical instrument natural gas. that uses two convex lenses to magnify protein Organic polymer formed from distant objects. amino acids. refraction The bending of waves, caused by proton Atomic particle with a positive changing their speed. charge that is part of an atom's nucleus. resistance The opposition to the flow of A simple machine consisting of a electrons through a conductor; measured in grooved wheel with a rope or a chain ohms. running along the groove. resistance arm - The part of a lever that quality In sound, the difference among exerts the resistance force. sounds of the same pitch and loudness. resistance force - The force exerted by a quarks Very small particles of matter that machine to overcome resistance to gravity or make up protons and neutrons; presently six friction. different types are known. resonance The tendency of an object to radiation The transfer of energy in the form vibrate at the same frequency as another of waves. It is a type of energy transfer that vibrating source. does not require matter. reverberation The echoing effect produced radiator A device with a large surface area by multiple reflections of sound. that transfers heat to surrounding air by RNA A nucleic acid that controls production conduction. of proteins that make new cells. radio waves - Electromagnetic waves that ROM In a computer, it is permanent have long wavelengths and are used in memory stored inside the computer, even communications. when the power is turned off. radioactive element - An unstable element salt A compound formed during a whose nucleus brakes down and gives off neutralization reaction when negative ions particles, radiation, and energy. from an acid combine with positive ions radioactivity The emission of high-energy from a base. radiation or particles from the nucleus of a saponification The process of making soap. radioactive atom. saturated hydrocarbon - A hydrocarbon RAM In a computer, temporary memory that contains only single-bonded carbon that is lost when the computer is turned off. atoms; an example is propane. rarefaction In compressional waves, the saturated solution - A solution that has less dense area of the wave. dissolved all the solute it can normally hold reactants The starting substances in a at a specific temperature. chemical reaction. scientific law - A rule that describes, but - An image produced where light does not explain, a pattern in nature and rays converge, as with a concave mirror or predicts what will happen under specific convex lens. conditions. PHYSICAL SCIENCE VOCABULARY

A simple machine consisting of a solution A homogeneous mixture containing special type of inclined plane wrapped in a particles so tiny that they cannot be seen spiral around a cylindrical post. even with a microscope. second The SI unit for time. solvent The substance that dissolves a semiconductor An element that conducts solute. electricity under certain conditions. specific heat - The amount of energy series circuit - An electrical circuit where needed to raise the temperature of 1 kg of the current has only one path. If the path is material 1 K; it is measured in joules per interrupted in any point, it stops current flow kilogram per kelvin. in the entire circuit. speed The rate of motion, or the rate at SI Standard, easy to use, worldwide system which a body changes position. of measurement based on powers of ten. The standard In measurement, an exact quantity standards are used by all scientists, and are a that everyone agrees to use as a basis of modern version of the metric system. comparison. simple machine - A device that state of matter - Any of the four conditions accomplishes work with only one in which matter can exist: solid, liquid, gas, movement. The lever, pulley, wheel and or plasma. axle, inclined plane, screw, and are static electricity - The net buildup of all examples. electric charges on an object. single displacement reaction - A chemical step down - An electrical reaction in which one element replaces transformer that decreases the voltage of a another element in a compound. power line. soap An organic salt made by reacting fats step up transformer - An electrical or oils with a strong base such as sodium transformer that increases the voltage of a hydroxide. power line. solar collector - A strong acid - An acid that ionizes almost device that absorbs completely in solution; for example, radiant energy from hydrochloric acid and sulfuric acid. the sun that can be strong base - A base that dissociates converted to completely in solution; for example, sodium thermal energy and hydroxide. used to heat sublimation The process in which a solid buildings. changes directly to a vapor without forming solar energy - Energy from the sun. It is a liquid. free and can be converted into thermal substance Matter that is an element or a energy to heat homes and other buildings. compound. solubility The amount of a substance that substituted hydrocarbon - A hydrocarbon will dissolve in a solvent; generally in which one or more hydrogen atoms have expressed as the maximum number of grams been replaced by atoms of other elements. of solute that will dissolve in 100 g of a supercollider A device to make protons solvent at a specific temperature. collide at high speed so they break apart into solute The substance being dissolved in a quarks. solvent.

PHYSICAL SCIENCE VOCABULARY

superconductor A supercooled material damage or destroy plants and animals that that has no electrical resistance; a current live there. can flow indefinitely through a thermonuclear fusion - Nuclear fusion that superconductor without losing energy. occurs under conditions of supersaturated solution - An unstable enormous heat, as in a star. solution that contains more solute that a tidal energy - Energy produced saturated solution can at that same specific by the rise and fall of ocean temperature. levels; used to generate suspension A heterogeneous mixture electricity. containing a liquid in which larger particles time The interval between two events. eventually settle out. titration Process in which a solution of synthesis reaction - A chemical reaction in known concentration is used to determine which two or more substances combine to the concentration of an acidic or basic form a different substance. solution. synthetic fiber - A thin strand of synthetic total internal reflection - Occurs when all polymer that can be woven into fabrics; the light striking a surface between two examples include nylon and Kevlar fibers. materials is reflected totally back into the The practical use of scientific first material. information to improve the quality of human toxic Hazardous life. substance that can telephoto lens - A lens having a long focal injure living tissue. length and producing an enlarged, close-up tracer A radioisotope image of an object. used in medical temperature A measure of the average diagnosis to allow kinetic energy of the particles that make up a doctors to monitor sample of matter. human body functions, locate tumors, detect terminal velocity - The greatest velocity fluid movement, and so on. reached by a falling object. It is achieved transistor A semiconductor that amplifies when the force of gravity is balanced by air or strengthens an electrical signal or acts as resistance. a tiny off/on . theory The most logical explanation of why transformer A device that things work the way they do. A former can increase or decrease the hypothesis that has been tested with repeated voltage of an alternating experiments and observations and found current. always to work. transition element - An thermal energy - Total energy of a element in Groups 3-12 of material's particles, including both kinetic the periodic table; typically, these are metals energy and potential energy. with one or two electrons in their outer thermal expansion - A characteristic of energy level. almost all material that causes it to expand translucent materials - Materials that can when heated and contract when cooled. be hazily seen through because they allow thermal pollution - Pollution caused when some light to pass through them, but not waste heat raises the temperature of the enough for a clear image. environment. In bodies of water, it can

PHYSICAL SCIENCE VOCABULARY

transmutation- Changing one element to voltmeter -A galvanometer that measures another through radioactive decay. potential differences in volts and is placed in transparent materials - Materials that can parallel across a part of the circuit. be clearly seen through because they allow Volume- The amount of space occupied by light to pass through them. an object. - Any element wave -A rhythmic disturbance that carries having more than 92 protons, the atomic energy through matter or space. number of uranium. wavelength The distance between identical transverse wave - A type of wave where the points on two adjacent waves; for example, medium moves at right angles to the the distance between two crests or two direction the wave is traveling. troughs. trough The lowest point of a wave. weak acid - An acid that partially ionizes in Tyndall effect - The scattering of light by solution; for example, carbonic acid. particles in a mixture; this effect can be seen weak base - A base that partially dissociates in all colloids. in solution; for example, magnesium ultrasonic technology - Technology using hydroxide. high-frequency sound waves for many Wedge- A simple machine consisting of a different purposes such as medical moving inclined plane with one or two diagnoses, sonar, and jewelry cleaning. sloping sides; examples are knives and ultraviolet radiation - Electromagnetic chisels. waves that have a higher frequency than weight -The measure of the force of gravity visible light. of an object. unsaturated hydrocarbons - Hydrocarbons wet cell - A power source that generates that contain at least one double or triple electric current by a chemical reaction using bond between carbon atoms. a liquid electrolyte. unsaturated solution - A solution that is - A simple machine capable of dissolving more solute at a consisting of two different-sized wheels that specific temperature. rotate together, such as a doorknob. velocity -The speed and direction of a wide angle lens - A lens with a short focal moving body, such as a storm or a length that produces a relatively small image basketball thrown across a court. of an object, but includes much of the Venturi effect - Reduction in pressure of a object's surroundings. fluid resulting from the speed increase as work -The transfer of energy through fluids are forced to flow faster through motion. narrow spaces. X rays - Electromagnetic waves having a virtual image - An image formed of wavelength shorter than ultraviolet diverging light rays, as in a plane or convex radiation; often used in medical diagnosis mirror, or seen through a concave lens. and photography because they can penetrate visible radiation - Electromagnetic waves human tissue. in the only part of the electromagnetic spectrum we can see--light. volt The unit for measuring electrical potential energy. voltage A difference in electrical potential, measured in volts with a voltmeter.