Vocab

Absorbers- objects that have the ability to absorb radiant energy. Accelerate- to increase speed or change direction. Acceleration- change in speed over time. Acid- a chemical that contributes hydrogen ions, H+, to a solution Acid Precipitation- rain, snow, or fog that has a pH lower than 5.6 Acid Rain- rain that has a pH lower than 5.6 Acoustics- the science and technology of sound. Addition Reaction- a chemical reaction in which two or more substances combine to form a new compound Additive primary colors- red, green, and blue Air Friction- the opposing force created by objects moving through air. Albedo- the percentage of the sun’s light reflected from a planet’s surface. Alloys- solutions of two or more metals Alpha Decay- radioactive decay that results in an alpha particle (a helium nucleus) being emitted from the nucleus of a radioactive element. Alpha Particles- a partially charged particle emitted from the nucleus of an atom during radioactive decay; also called a helium nucleus. Alternating Current- an electric current that reverses its direction at repeated intervals; the abbreviation for this is AC. Amperes- the unit for measuring electrical current; the abbreviation is amp. Amplitude- the maximum distance from the average in harmonic motion; amplitude is often a distance or an angle. Anhydrous- means “without water”; describes the state of a hydrate that has lost water through evaporation. Aquifer- an underground area of sediment and rocks where groundwater collects. Archimedes’ principle- a principle that states that the force exerted on an object in a liquid is equal to the weight of the fluid displaced by the object. Atmospheres- the unit used to measure atmospheric pressure; the abbreviation is atm. Atom- the smallest particle of an element that can exist alone or in combination with other atoms. Atomic mass- average mass of all the known isotopes of an element. Atomic mass unit- defined as the mass of 1/12 of a carbon-12 atom. Atomic Number- the number of protons that an atom contains. Atomic Theory- a theory that states that all matter is composed of tiny particles called atoms. Average Speed- how fast something moves over a certain distance. Avogardo’s number- the number of atoms in the atomic mass of an element, or the number of molecules in the formula mass of a compound when these masses are expressed in grams. Balance- occurs when the number and type of atoms on the reactant’s and product’s sides of a chemical equation are equal. Base- a chemical that contributes hydrowl ions, OH-, to a solution Battery- a device that uses chemical energy to move electrical charges. Beat- a rapid alteration between loudness and silence. Beta Decay- radioactive decay that results in a beta particle (an electron) being emitted from the nucleus of a radioactive element.

Beta Particles- a negatively charged particle (an electron) being emitted from the nucleus of a radioactive decay. Binary Compound- a covalent compound that consists of only two types of elements. Boyle’s law- pressure and volume are inversely related. British thermal unit (Btu)- the quantity of heat it takes to increase the temperature of one pound of water by 1 degree F. Brittleness- a measure of a material’s tendency to shatter upon impact. Buoyancy- a measure of the upward force a fluid exerts on an object. Buoyant Convection- see natural convection. Calorie- the quantity of heat required to raise the temperature of one gram of water by 1 degree C. Carbohydrate- a nutrient molecule composed of simple or complex sugars; it contains four calories of energy per gram. Carbon Dating- a technique to find out how old something is Cause and Effect- the relationship between an event that brings about a result and what happens due to the result. Celsius Scale- a temperature scale on which zero equals the temperature that water freezes and 100 is the temperature that water boils, where C stands for Celsius. Charles’ law- the volume of a gas increases with increasing temperature if pressure is held constant. Chemical Bond- an attraction between two or more different atoms that binds them together. Chemical Change- a change in a substance that involves the breaking and reforming of chemical bonds to make a new substance or substances. Chemical Energy- a type of energy stored in molecules. Chemical Equation- chemical formulas (Emma’s cool) and symbols that represent a chemical reaction Chemical Formula- a representation of a compound that includes the symbols and numbers of atoms in the compound. Chemical Potential Energy- the energy that is stored in chemical bonds. Chemical Reaction- the breaking of bonds to form new substances Chemical Symbol- an abbreviation that represents the name of an element. Circuit- see electric circuit Circuit Diagram- the diagrammatic representation of an electric circuit. Circular Waves- waves that move in concentric circles. Closed Circuit- a circuit in which the switch is turned to the “on” position, causing there to be no breaks anywhere in the wire. Cochlea- a tiny, fluid-filled bone structure in the inner ear with three tubes and a spiral. Coefficient- a number placed in front of a chemical formula to make the number of atoms on each side of a chemical equation equal. Colloid- a type of mixture in which the particles (atoms or molecules) are between 1.0 and 1000 nanometers in diameter. Combustion Reaction- a reaction in which a substance combines with oxygen, releasing large amounts of energy in the forms of heat and light. Compounds- substances made of two or more elements that cannot be separated by physical means.

Compression Stroke- in a four-stroke engine, the stroke in which the fuel and air are compressed and ignited by a spark plug. Conceptual Model- a written description or diagram based on ideas and observations that are used to describe how a process or object works. Condensation- the process by which a substance in its gaseous state loses energy and enters its liquid state Cone Cells- photoreceptor cells in the retina of the eye that respond to color. Conservation of Atoms- principle that states the number of each type of atom on the reactant’s side must be equal to the number of each type of atom on the product’s side of a chemical reaction. Consonance- a combination of sounds that is harmonious or agreeable. Constructive Interference- occurs when waves add up to make a larger amplitude. Continuous- connected to itself. Controlled Experiment- when one variable is changed and all the others are controlled or stay the same throughout the experiment. Controlled Variables-variables in an experiment that are kept the same throughout the experiment. Convection-occurs when hot air rises upward due to a decrease in density, and then expands, giving off heat. Converge- to bend light so that the rays come together. Converging Lens- a type of lens that bends light so that the parallel rays coming in bend toward the focal point. Coulomb- the unit for electrical charge. Covalent Bond- a type of chemical bond that is formed when two atoms share electrons. Covalent Compound- a compound that consists of atoms that are covalently bonded. Crest- the high point on a wave. Critical Angle- the angle at which light is totally reflected back into a material. Current- the quantity that refers to the rate of flow of electric charges; current is measured in amps. Cyan- a greenish, light-blue that is created when red is absorbed and blue and green are reflected. Cycle- a unit of motion that repeats over and over. Deceleration- occurs when change in speed, or acceleration, is in the negative direction. Decomposition reaction- a chemical reaction in which a single compound is broken down to produce two or more smaller compounds. Density- a property that describes the relationship between mass and volume. Dependent Variable- the variable in an experiment that changes in response to choices made by the experimenter. Destructive Interference- occurs when waves add up to make a smaller amplitude. Dew Point- the temperature at which air becomes saturated with water. Diatomic Molecules- a molecule that has only two atoms of the same element. Diffraction- the process by which waves can bend around corners or pass through openings. Direct Current- electrical current flowing in one direction only; abbreviation is DC Dissolution Reaction- a reaction that occurs when an ionic compound dissolves in water to make an ionic solution.

Dissolved- the state in which solute particles are evenly distributed through a solvent. Dissolving Rate- the length of time it takes for a certain amount of solute to dissolve in a solvent Dissonance- a combination of discordant or unsettling sounds. Distance- the length of space between two points. Diverge- bending light so that the rays spread apart. Diverging Lens- a type of lens that bends light away from the focal point. Double-Displacement Reaction- a reaction in which ions from two compounds in a solution exchange places to produce two new compounds. Efficiency- the ratio of a machine’s output work to input work. Elasticity- a measure of a solid’s ability to stretch and then return to its original shape and size. Electric Circuits- the structures that provide paths through which electricity travels. Electric Motor- a device that uses electricity and magnets to turn electrical energy into rotating mechanical energy. Electrical Conductivity- the ability of a material to conduct (or carry) electricity. Electrical Conductor- a material that easily carries electrical current. Electrical Energy- another term for electricity. Electrical Force- the force that charged materials or objects exert on each other. Electrical Insulator- a material that poorly conducts current. Electrical Symbols- simple symbols used in circuit diagrams. Electrically Charged- an object that has an excess amount of either positive or negative charges. Electrically Neutral- an object that has equal amounts of positive and negative charges. Electrolytes- chemicals that form ions and conduct current when dissolved in water. Electromagnet- a strong, short lasting magnet that can be made by inserting iron into a wire coil that is conducting an electric current. Electromagnetic Force- the force that exists between electric charges; often described as electrical force or magnetic force depending on how charges interact. Electromagnetic Induction- the creation of electric current when a magnet is moved inside a loop of wire; generators are devices that work using electromagnetic induction. Electromagnet Spectrum- the whole range of light Electron- a subatomic particle in an atom that is negatively charged and that occupies the energy levels in an atom. Electronegativity- the attraction an atom has for the shared pair of electrons in a chemical bond. Electroscope- an instrument that is used to detect charged objects. Elements- substances that contain only one kind of matter. Emissions- the airborne gases and particles expelled through an operating automobile’s tailpipe. Emitters- objects that have the ability to emit radiation efficiently. Endothermic Reaction- a reaction in which more energy is required to break the bonds in reactants than is released from the formation of new bonds in the products. Energy- a fundamental building block of the universe

Energy Level- a region around the nucleus of an atom where electrons are most likely to be found; only a certain number of electrons can be found in each energy level of an atom. Energy Transformation- the conversion from one kind of energy to another kind of energy; for example, an energy transformation occurs when potential energy is converted to kinetic energy. Engineering- the applications of science to solve technical problems. English System- a system of measuring that uses, for example, distance units in inches, yards, and miles. Equilibrium- 1. in physics, occurs when the forces on an object are balanced, 2. in chemistry, the state in which the solute in a solution is dissolving and coming out of solution at the same rate. Evaporation- the process by which a substance in its liquid state gains energy and enters its gaseous state; one phase of the water cycle. Excess Reactant- a reactant that is not completely used up. Exhaust Stroke- in a four stroke engine, the stroke in which a valve opens and releases exhaust gases. Exothermic Reaction- occurs when less energy is required to break the bonds in reactants than is released when bonds are formed to make new products. Experiment- any situation that is set up to observe and measure something happening. Experimental Technique- the exact procedure that is followed each time an experiment is repeated. Experimental Variable- a variable in an experiment that is changed by the experimenter; the experimental variable is plotted as an independent variable on the x-axis of a graph. External Combustion Engine- a machine in which the action of heating takes place outside it, as in a steam engine. Fahrenheit Scale- a temperature scale on which water freezes at 32˚F and water boils at 212˚F. Fat- a nutrient molecule that is composed of carbon and hydrogen atoms, and that contains 9 grams of energy per gram. First Law of Thermodynamics- states that energy in a closed system is conserved. Fission- a nuclear reaction that involves the splitting of the nucleus of an atom. Fluorescent- a type of electrical light bulb. Focal Length- the distance from the center of a lens to the focal point. Focal Point- the point at which light rays meet after having entered a converging lens parallel to the principal axis. Focus- the place where all the light rays that have come from an object meet to form an image after having passed through a converging lens. Force- a push, a pull, or any action that has the ability to change motion. Forced Convection- occurs when mechanical means is used to force fluid or gas to move. Formula Mass- determined by adding up the atomic mass units of all the atoms in the compound; a way to compare the masses of molecules of different compounds. Fossil Fuels- hydrocarbon substances including oil, coal, and natural gas that are extracted from the Earth; fossil fuels are used as the primary source of energy in the US.

Free Fall- the acceleration of a falling object under the influence of the Earth’s gravitational force. Frequency- 1. in harmonics, the number of cycles an oscillator makes per second; 2. in waves, the number of wavelengths that pass a given point in one second. Friction- the force that results from relative motion between objects. Fulcrum- a fixed point on a lever. Fundamental- the name of the first harmonic. Fusion- a nuclear reaction that involves fusing nuclei from two atoms to make a different atom. Gamma Ray- a photon emitted spontaneously by a radioactive substance. Gear- a wheel with teeth; two or more gears can be connected together to change the speed and/or direction of rotating motion. Generator- a combination of mechanical and electrical systems that converts kinetic energy into electrical energy. Global Warming- an increase in the Earth’s Temperature due to increased carbon dioxide in the atmosphere. Graphical Model- a model that shows the relationship between two variables on a graph so that the relationship is easily seen and understood. Gravity- the attractive force that exists between any two objects that have mass. Groundwater- water that collects underground in an aquifer; this water supplies wells and springs. Group of Elements- elements that exhibit similar chemical properties; arranged in columns on the periodic table. Half-life- the length of time it takes for half an amount of radioactive substance to undergo radioactive decay. Hardness- measures a solid’s resistance to scratching. Harmonic Motion- motion that repeats itself. Harmonics- 1. frequencies that are multiples of fundamental notes; 2. multiples of natural frequency. Heat- a flow of thermal energy from one object to another object due to a temperature difference. Heat Transfer- the transfer of energy in the form of heat from a material at a higher temperature to a material at a lower temperature. Heat-Temperature Rule- a rule stating that the more heat you add to an object the greater the increase in temperature. Hertz- a unit of one cycle per second used to measure frequency; the abbreviation is Hz Heterogeneous Mixture- a mixture in which every sample of it might have a different composition. Homogeneous Mixture- a mixture in which every sample of it has the same composition Horsepower- a unit of power Humidity- a measurement of how much water vapor is in the air. Hydrate- a compound that has water molecules chemically bonded to its ions. Hydrated- a compound that has water molecules chemically bonded to its ions. Hydrochloric Acid- a highly acidic substance your stomach normally produces to help you break down food.

Hydrogen Bond- a weak bond between the partially charged positive end of one water molecule and the partially charged negative end of another water molecule. Hydrologic Cycle- describes how water moves around the Earth by the processes of evaporation, condensation, precipitation, and transpiration. Hypothesis- a prediction that can be tested by experimentation. Image- a picture of an object that is formed using a mirror or lens where light rays from the object meet. Incandescence- the process of making light with heat. Incident Ray- the ray that comes from an object and strikes a surface. Independent Variable- the variable in an experiment that is manipulated by the experimenter and that causes changes in the dependent variable in the experiment. Index of Refraction- a ratio that tells how much the speed of light is reduced when it passes through a material. Inertia- the reluctance of a body to change its state of motion. Infrared Light- electromagnetic radiation, including heat, with wavelengths longer than the visible spectrum. Input- includes everything you do to make a machine work. Input Arm- when you place a lever on a fulcrum, the input arm is the side of the lever where the input force is applied. Input force- the force applied to a machine Insoluble- a term to describe a substance that does not dissolve in water. Instantaneous Speed- the speed of an object at a specific point in its journey. Intake Stroke- in a four-stroke engine, the stroke in which air and fuel enter the cylinder. Internal Combustion Engine- a machine in which the burning process takes place inside the cylinder. Investigation- one or more experiences that are all connected to answering the same basic question. Ion- an atom that has an electrical charge. Ionic Bond- a type of chemical bond between atoms that gained or lost electrons; a bond between ions. Ionic Compound- a compound that is made up of ions. Isotopes- forms of the same element that have different numbers of neutrons and different mass numbers. Joule- a unit measuring work Kilocalories- the amount of heat required to raise the temperature of one kilogram of water 1 degree C. Kilowatt- a measurement equal to 1000 watts or 1000 joules used for one hour. Kinetic Energy- Energy that comes from motion. Kirchhoff’s Current Law- states the current into a branch in a circuit equals the amount of current out of the branch. Kirchhoff’s Voltage Law- states that over an entire circuit, the energy taken out must equal the energy supplied by the battery. Latent Heat- heat that cannot be sensed with a thermometer; the heat released when vapor condenses into a liquid. Latitude- angular distance north and south from the Earth’s equator measured through 90 degrees.

Law of Conservation of Mass- states that the total mass of products of a reation is equal to the total mass of reactants. Law of Conservation of Momentum- states that as long as interacting objects are not influenced by outside forces (like friction), their momentum before the interation will equal their momentum after the interaction. Law of Universal Gravitation- the force of attraction between two objects is directly related to the masses of the objects and indirectly related to the distance between them. Length- a unit of measurement for distance. Lens- a shaped of a transparent material, like glass, that is used to bend light rays. Lever- a stiff structure that rotates around a fixed point called the fulcrum. Limiting Reactant- the reactant that is used up first in a chemical reaction. Longitudinal Wave- a wave whose oscillations are in the same direction as the wave moves. Machine- a type of mechanical system. Magenta- a pink-purple color that is created when green is absorbed and red and blue are reflected. Magnetic Field- an area of magnetic force that surrounds magnetic objects. Magnetic Force- a force exerted on a particle or object traveling in a magnetic field. Magnetic North Pole- the end of a magnetic object that points toward the geographic north pole of the Earth. Magnetic South Pole- the end of a magnetic object that points away from the geographic north pole of the Earth. Malleability- a solid’s ability to be pounded into thin sheets. Mass- a measure of the inertia of an object; the amount of matter an object has. Mass Number- the total number of protons and neutrons in the nucleus of an atom. Matter- Anything that has mass and takes up space. Measurement- the act or process of measuring in multiples of a specific unit. Mechanical Advantage- the ratio of output force to input force. Mechanical System- a series of interrelated, moving parts that work together to accomplish a specific task. Metabolic Rate- the rate of energy consumption at all times within the body. Metric System- a system of measuring that uses distance units of millimeters, centimeters, meters, and kilometers. Mixture- substance that contains more than one kind of matter. Mole- one set of 6.02 x 10 to the 23 power, atoms or molecules. Molecular Formula- includes the symbols for and number of atoms of each element in a compound. Molecule- the smallest particle of a compound that retains the properties of the compound. Momentum- the mass of an object multiplied by its speed or velocity. Monoatomic Ions- ions that contain only one type of atom. Musical Scale- Frequencies of sound that fit into a special pattern. Nanometer- a unit of measurement that is equal to one billionth of a meter. Natural Convection- a process that is influenced by gravitational forces and by which hot, less dense air displaces cooler denser air.

Natural Frequency- describes how an object vibrates; for example, a guitar string strummed repeatedly has its own natural force. Natural World- the aspects of the world not created or constructed by people. Negative Charge- one of two types of electric charge. Net Force- the amount of force that overcomes an opposing force to cause motion. Neutral- 1. a solution that has a pH of 7 2. when one proton is paired with one electron. Neutron- an uncharged particle found in the nucleus of an atom. Newton- a unit of force; Abbreviation is N. Newton’s first law of motion- states any object at rest will remain at rest unless acted on by an unbalanced force. Newton’s second law of motion- states that the acceleration of an object is directly proportional to the force acting on it and inversely proportional to its mass. Newton’s third law of motion- states that whenever one object exerts a force on another, the second object exerts an equal and opposite force on the first. Nonpolar- a term used to describe a molecule or covalent bond that does not have partial charges; oils and fats are nonpolar molecules. Normal- a line that is perpendicular to the surface of an object. Nuclear Energy- the form of energy that comes from splitting the nucleus of an atom, or fusing two nuclei of an atom. Nuclear Reaction- a reaction that involves splitting the nucleus of an atom or fusing two nuclei. Nucleons- the protons and neutrons in the nucleus of an atom. Nucleus- the center core of an atom that contains protons and neutrons. Octet- an atom’s eight valence electron Octet Rule- states that atoms form bonds with other atoms by sharing or transferring them to complete their octet and become stable. Ohm- the unit of measurement for electrical resistance Ohm’s Law- describes the mathematical relationship present in most circuits. Open Circuit- a circuit in which there is a break in the wire so that current cannot flow. Optics- the study how light behaves Oscillator- a system that shows harmonic motion. Output- what the machine does. Output Arm- of the lever on a fulcrum, the output arm is the side where output force is applied. Output Force- the force a machine applies to accomplish a task. Oxidation Number- indicates how many electrons are lost or gained (or shared) when bonding occurs. Parallel- lying or moving in the same direction, but always the same distance apart. Parallel Circuit- a circuit in which the current can take more than one path. Pascal (Pa)- the SI unit of pressure. One Pascal is equal to one Newton of force acting on one square meter of surface. Percent Yield- the actual yield of product in a chemical reaction divided by the predicted yield, and multiplied by one hundred to get a percentage. Period- the time for one cycle. Periodic Motion- cycles of motion that repeat over and over again; the same as harmonic motion.

Periodic Table of Elements- a table that visually organizes the similarities between all known elements. Permanent Magnet- a magnetic object that retains its magnetic properties without external influence. Perpendicular- forming a 90 degree angle with a given edge or surface. pH- the exact concentrations of H+ ions and OH- ions in a solution. pH indicator- a solution or object that changes color to identify the pH of a solution. PH scale- a scale that runs from 0(strongly acidic) to 14 (strongly basic, or alkaline) Phase- refers to where an oscillator is in its cycle. Photoluminescence- occurs when light energy makes something else give off light. Photoreceptors- rod and cone cells in the retina of the eye that receive light and release a chemical signal that travels down the optic nerve to the brain. Photosynthesis- a chemical reaction performed by plants in which energy from the sun is converted to chemical energy. Physical Change- change in the physical properties of a substance. Physical Models- models that are made of materials and that can be touched and measured. Pitch- Property of a sound determined by the frequency of the waves producing it. Pixel- a dot on your computer screen whose color can change depending on the three numbers your computer assigns to it. Plane Waves- waves that move in straight lines. Polar- something that has two poles; a term used to describe molecule or covalent bond that has partial charges; water is a polar molecule. Polarization- a way of describing the direction (such as vertical or horizontal) that waves of light travel. Polarizer- a partially transparent material that lets through only one polarization of light. Polyatomic Ions- ions that contain more than one type of atom. Polymer- a large molecule that is composed of repeating smaller molecules called subunits or monomers. Polymerization- the production of a very large molecule by a series of synthesis reactions. Position- a point in space of an object compared to where it started. Positive Charge- one of two types of electrical charge. Potential Energy- stored energy that comes from position. Potentiometer- a variable resistor. Pounds- the rate at which work is done. Power- the rate at which work is done. Power Stroke- in a four-stroke engine, the stroke in which the ignited fuel expands and pushes the piston back. Precipitate- substance formed when one of the compounds in a double-displacement reaction is insoluble, or does not dissolve in water. Precipitation- water vapor in the atmosphere falling back to Earth in the form of rain, hail, sleet, or snow Pressure- a measure of the force felt by the walls of a container. Pressure- the force acting on a unit area of surface. Procedure- a collection of all the techniques you use to do an experiment.

Products- substances that are produced in a chemical reaction from reactants. Protein- a nitrogen-conatining molecule found in foods that is used to build structural parts of cells and to facilitate cellular reactions. Proton- a subatomic particle identical with the nucleus of the hydrogen atom. Prototype- a working model of a design that can be tested to see if it works. Radiant Energy- another term for electromagnetic energy. Radiation- 1. the process of emitting radiant energy; 2. a term to describe the particles and energy that are emitted from radioactive substances. Radiation- a type of heat transfer that occurs by electromagnetic waves. Radioactive- a term to describe an atomic state when the nucleus is emitting radiation in the form of particles and energy until it becomes more stable. Radioactive isotope- an unstable isotope of an element that spontaneously undergoes radioactive decay. Ray Diagram- a diagram which illustrataes how several light rays behave as they go through an optical system. React- describes how atoms interact when forming a chemical bond with another atom. Reactants- a substance that enters into and is altered in the course of a chemical reaction. Real Image- an image formed by rays of light coming together on a surface like a screen or the retina of the eye. Recoil- backward acceleration from the reaction force. Reflected ray- the ray that bounces off an object. Reflection- the bounce of a wave off a surface. Reflectors- objects that reflect light. Refraction- occurs when light passes from one transparent material into another and bends. Relative Humidity- the amount of water vapor in the air. Relative Mass- a quantity that allows for comparison between amounts of matter that are very small. Research Question- a question that is solved through investigation. Resistance- the measure of an object’s ability to conduct circuits. Resistors- components that are used to control current in many circuits. Resonance- an occurrence whereby the natural frequency of a system is exactly in tune with a force applied to the system. Reverberation- multiple echoes of sound. Rod Cells- photoreceptor cells in the retina of the eye that respond to differences in brightness. Rolling Friction- resistance created when one object rolls over another one. Saturated- the state of a mixture in which the maximum amount of solute has dissolved in a solution. Scientific Evidence- any observation that can be repeated with the same results. Scientific Method- a process that is used to gather evidence that leads to understanding. Scientific Model- a method of representing the relationship between variables. Sea Breeze- air current created when hot air rises over land due to convection and is replaced by cooler air. Second- a commonly used unit of time Semiconductor- material between conductor and insulator in its ability to carry current.

Series Circuit- a circuit in which the current only has one path. Short Circuit- a branch in a circuit with zero or very low resistance. Simple Machine- an unpowered mechanical device, such as a lever, which has an input and an output force. Single-Displacement Reaction- a reaction in which one element replaces a similar element in a compound. Sliding Friction- resistance created when two surfaces rub against one another. Solar Power- radiant energy from the sun that is harnessed for use. Solubility- refers to the amount of solute that can be dissolved in a certain volume of solvent under certain conditions. Solubility rules- a set of rules that identifies whether a combination of ions will dissolve or form a precipitate in water. Solubility Value- a number that describes a solute-solvent system; it includes the mass of solute, amount of solvent, and temperature. Solute- the substance in a solution in the smallest amount; the solute is dissolved by the solvent. Solution- a mixture of two or more substances that is homogenous at the molecular level; a solution consists of a solute and a solvent. Solvent- the component of a solution that dissolves the solute and is present in the greatest amount. Sonogram- special kind of graph that shows how loud sound is at different frequencies. Spectral Diagram- a diagram that shows the wavelengths and intensities of light emitted from a light source. Speed- describes movement from one place to another over time; distance divided by time. Stable- 1. a term used to describe an atom that has a balance of charge; 2. a nonradioactive nucleus. Standing wave- a wave trapped in one spot. Static Electricity- a buildup of either positive or negative charge; consists of isolated motionless charges, like those produced by friction. Strong Nuclear Force- the force that holds protons together when they are very close together (only 10 to the –15th power, meters apart) Subatomic Particles- particles that are smaller than an atom Subscript- a number in a chemical formula that show the number of a type of atom. Substance- a mixture that cannot be separated into different kinds of matter using physical means. Subtractive Primary Colors- magenta, yellow, and cyan. Supersaturated- condition of a solution when more solute has dissolved than is normall possible at a given temperature. Supersonic- motion that is faster than sound. Surface runoff- water that flows over land until it reaches lakes, rivers, or other surface water areas. Surface Water- water contained in places such as lakes, ponds, rivers, streams, and reservoirs. Suspensions- a type of mixture in which the particles (atoms or molecules) are larger than 1000 nanometers in diameter.

System- a collection of matter and processes that occur in a certain space and can be studied; systems can be open or closed. Temperature- the measurement used to quantify the sensations of hot and cold Tensile Strength- a measure of how much pulling, or tension, a material can withstand before breaking. Terahertz- a unit of measurement that is equal to 1,000,000,000 cycles per second. Thermal Conductivity- the ability of material to transfer heat. Thermal Conductor- a material that easily conducts heat. Thermal Energy- energy that comes from heat and the vibration of atoms and molecules. Thermal Equilibrium- a state that results when heat flows from a hot object to a cold object until they are at the same temperature. Thermal Insulators- materials that are poor conductors of heat. Thermometer- an instrument for measuring the temperature Thermostat- a device that controls another device based on changes in temperature. Time- a useful measurement of changes in motion or events Total Internal Reflection- occurs when light within a material approaches the surface at greater than the critical angle and reflects back. Transpiration- process in which plants open tiny pores on their leaves to gain carbon dioxide but lose water; one phase in the water cycle. Transverse Wave- a wave whose oscillation is perpendicular to the direction the wave travels. Trial- each time an experiment is tried. Trough- the low point on a wave. Turbine- an engine whose central driveshaft is fitted with curved vanes spun by the pressure of water, steam, or gas. Tyndall effect- a way of visually distinguishing colloids from true solutions. Ultraviolet light- light of a wavelength shorter than those of visible light but longer than those of X-rays. Unsaturated- a solution in which it is possible for more solute to be dissolved. Valence Electrons- the electrons in an atom that are involved in the formation of chemical bonds. Variables- factors that affect the result of an experiment. Velocity- describes movement from one place to another over time and in a certain direction. Versorium- the earliest version of today’s electroscope. Virtual Image- an image formed when rays of light appear to be coming from a place other than where the actual object exists; a virtual image cannot be projected on a screen. Viscosity- a measure of a material’s resistance to flow. Viscous Friction- resistance created by objects moving in water or other fluids. Visible Light- the light you can see in the range between 400 and 700 nanometers. Volt- the measurement unit for voltage. Voltage- the amount of potential energy that each unit of electrical charge has. Water Cycle- see hydrologic cycle. Watt- the metric, or SI, unit of power. Wavefronts- another term used to describe the crests of a wave.

Wavelength- the distance from peak to peak, crest to crest, or trough to trough of a wave. Weight- a force created by gravity White Noise- an equal mixture of all frequencies, like white is a mixture of all colors. Work- the quantity of force times distance; the result of machines performing task. Yellow- a color that is created when blue is absorbed and red and green are reflected.