| A | B |
|---|
| Variable | The factor bgeing tested in an experiment |
| Control | An experiment run without a vaarialbe in order to show that any data from the expeerimental setup was due only to the variable that was being tested |
| Hypothesis | Proposed solution to a scientific problem |
| Law | Summarizing statement ovserved experimental facts that has been tested many times and is generally accepted as true |
| Conclusion | A solution to a scientific problem |
| Theory | A logical, time-tested explanation for events that occur in the natural world |
| Mass | The amount of matter in an object |
| Weight | Measure of the force of attraction between objects due to gravity |
| Density | Mass per unit volume |
| Temperature | Measure of the motion of molecules |
| Matter | Anything that has mass and volume |
| Gravity | Force of attraction that depends on the mass of two objects and the distance between them; responsible for accelerating an object toward the Earth |
| Volume | Amount of space an object takes up |
| Inertia | Tendency of objects to remain in motion or to stay at rest unless acted upon by an outside force |
| Chemical change | Process by which a substance becomes a new and different substance |
| Physical change | Process by which a substance changes phase |
| Plasma | Phase in which matter is extremely high in energy and cannot be contained by ordinary matter; very rare on Earth; found in stars |
| Condensation | Change of a gas to a liquid |
| Evaporation | Vaporization that takes place at the surface of a liquid |
| Vaporization | Change of a liquid to a gas |
| Sublimation | Change from the solid phase directly into the gas phase |
| Amorphous | Solids that lose their shapes under certain conditions |
| Crystal | Solid in which the particles are arranged in a regular repeating pattern |
| Element | Simplest type of pure substance |
| Compound | Substance made up of molecules that contain more than one kind of atom; two or more elements chemically combined. |
| Mixture | Matter that consists of two or more substance mixed; but not chemically combined |
| Heterogeneous | Substance that does not appear to be the same throughout |
| Homogeneous | Substance that appears to be the same throughout |
| Soluble | Can be dissolved in another material such as water |
| Insoluble | Cannot be dissolved in another material |
| Colliod | Homogeneous micture in which the particles are mixed together but not dissolved |
| Solvent | Substance that does the dissolving in the solution |
| Solution | Homogeneous mixture of a few substances in a single physical state |
| Solute | Substance that is dissolved in a solution |
| Alloy | A solution of two metals or a metal and a nonmetal that has the properties of a metal |
| Atom | The smallest part of an element that has all the properties of an element |
| Molecule | Combination of atoms formed by a covalent bond |
| Nucleus | The center of an atom |
| Proton | A positively chared particle in the nucleus of an atom |
| Neutron | A neutral particle in the nucleus of an atom |
| Electron | A negatively charged particle found in an area outside the nucleus of an atom |
| Isotopes | Atom that has the same number of protons(atomic number) as another atom but a different number of neutrons |
| Energy | The ability to do work |
| Atomic Number | Number of protons in the nucleus of an atom |
| Atomic Mass | Weighted average of the mass numbers of an element's naturally occurring isotopes |
| Ductile | Able to be drawn into a thin wire |
| Malleable | Able to be hammered out into a thin sheet |
| Valence | Electron in the outermost energy level of an atom |
| Alkali Metals | Member of element Family 1 that has one valence electron |
| Inert | Member of Family 18 of the periodic table; elements have atoms with 8 valence electrons and unreactive |
| Ion | An atom that has become charged due to the loss or gain of electrons |
| Metalloid | Element that has properties of both metals and nonmetals |
| Covalent bond | Bone that involves the sharing of electrons |
| Ionic bonds | BOnd that involves the transfer of electrons |
| Electron affinity | Tendency of an atom to attract electrons |
| Diatomic | Element whose atoms can form covalent bonds with another atom of the same element |
| Polyatomic ion | Group of covalently bonded atoms that acts like a single atom when combining with other atoms |
| Reactant | Substance that enters into a chemical reaction |
| Product | Substance producedby a chemical reaction |
| Synthesis | Chemical reaction in which two or more simple substances combine to form a new, more complex substance |
| Single Replacement | Chemical reaction in which an uncombined element replaces an elment that is part of a compound |
| Double Replacement | Chemical reaction in which different atoms in tow different compounds replace each other |
| Endothermic | Chemical reaction in which energy is absorbed |
| Exothermic | Chemical reaction in which energy is released |
| Activatioin energy | Energy required for a chemical reaction to occur |
| Acid | Compound with a pH above 7 that tastes our, turns blue litmus paper red; produces hydorgen ions |
| Base | Compound with a pH above 7 that tastes bitter, is slippery to the touch, turns red litmus paper blue |
| pH | Measuer of the Hydronium ion concentration, scale 1-14 |
| Hydronium ions | A positively charged hydrogen ion |
| Hydroxide | A negatively chared oxygen and hydrogen molecule |
| Radioactivity | Release of energy and matter that results form changes in the nucleus of an atom |
| Fusion | Joining of two atomic nuclei of smaller mass to form a single nucleus of larger mass |
| Half-life | Amount of time it takes for half of the atoms in a given sample of an element to decay |
| Decay | Sequence of steps by which a radioactive nucleus decays into a nonradioactive nucleus |
| Velocity | Description of speed in a given direction |
| Speed | Rate at which an object moves; distance / time |
| Acceleration | Rate of change in velocity |
| Deceleration | The decrease in the velocity of an atom |
| Momentum | Mass of an object time its velocity |
| Force | Push or pull that gives energy to an object, sometimes causing a change in the motion of the object |
| Pressure | Force that particles if a fluid exert over a certain area due to weight and motion |
| Buoyancy | Upward force in a fluid that exists because the pressure of a fluid varies with depth |
| Work | Force acting over a distance to move an object |
| Power | Rate at which work is done or energy is used |
| Resistance force | Opposition to the flow of electric charge |
| Mechanical advantage | Number of times a machine multiplies the effort force |
| Efficiency | Comparison of work input to work output |
| Fulcrum | Fixed pivot point of a lever |
| Simple machine | An instrument that makes work easier |
| Compound machine | One or more simple machines joined together |
| Energy | Ability to do work |
| Mechanical energy | Energy associated with motion |
| Nuclear energy | Energy released when a nucleus splits or combines |
| Chemical energy | Energy that bonds atoms or ions together |
| Heat energy | Energy involved in the internal motion of particles of matter |
| Electromagnetic energy | Energy associated with moving charges |
| Potential energy | Energy of shape or position, stored energy |
| Kinetic energy | Energy of motion |
| Gravitational potential energy | Potential energy that is dependent on height above the Earth’s surface |
| Heat | Form of energy caused by the internal motion of molecules of matter |
| Kelvin | Metric temperature scale which O K represents absolute zero . Water freeze at 273 K and boils at 373 K. |
| Convection | Heat transfer in liquids and gases by means of rising and falling. |
| Conduction | Heat transfer through direct contact |
| Radiation | Heat transfer through space |
| Specific Heat | Ability of a substance to absorb heat energy |
| Thermal expansion | Expansion of a substance due to heat |
| Insulatioin | Prevention of heat loss by reducing the transfer of heat by conduction and convection |
| Absolute zero | Temperature at which all molecular motion ceases; lowest possible temperature |
| Calorimeter | Instrument used to measure the heat given off in chemical reactions |
| Conductor | Material which permits electrons to flow freely or transfers heat more easily that other substances |
| Electric field | Region of space around a charged particle in which a force is exerted on other chared particles |
| Induction | Method of charging an object by rearranging its electric charges into groups of positive charge and negative charge |
| Static electricity | Movement of charges from one object to another without further movement |
| Electroscope | Device consisting of a metal rod with tow thin metal leaves at one end that can be used to detect radioactivity or charge |
| Electric discharge | Loss of static electricity a electric charges move off an object |
| Circuit | Complete path through which electricity can flow |
| Resistor | A material the opposes the flow of electric charge |
| Series circuit | Circuit in which all parts are connected one after another; if one part fails to operate properly, the current connot flow |
| Parallel circuit | Circuit in which different parts are on sepaarate branches; if one part does not operate properly, current can still flow through the others. |
| Amperes | The unit for the current |
| Ohms | The unit for resistance in electricity |
| North pole/South pole | An area of the magnetic field where magnetism is concentrated |
| Magnetoshpere | Region of a material in which the magnetic fields of individual atoms are aligned |
| Aurora | Glowing region of air caused by solar particles that break through the Earth's magnetic field |
| Magnetic field | Area over which the magnetic force is exerted |
| Electromagnietic induction | Process by which a current is produced by a changing magnetic field |
| Generators | Device that uses electromagnets to convert mechanical energy to electrical energy |
| Solenoid | Long coil of wire that acts like a magnet when current flow through it |
| Medium | Material through which mechanical wave travels |
| Wave | Traveling disturbance that carries energy from one place to another |
| Transverse wave | Wave in which the motion of the medium is at right angles to the dierction of the wave (up and down wave) |
| Longitudinal wave | Wave in which the motion of the medium is parallel to the direction of the wave (in and out motion) |
| crest | the high point of a wave |
| trough | the low point of a wave |
| wavelength | distance between two consecutive similar points on a wave |
| amplitude | height of a wave |
| refraction | bending of waves due to a change in a wave |
| reflection | Bouncing back of waves due to a change in speed |
| diffraction | bending of waves around the edge of an obsticle |
| interference | interaction of waves that occur at the same place at the same time |
| Frequency | Number of waves that pass a certain point in a given amount of time |
| Hertz | The unit of the frequency of a wave |
| Constructive interference | Type of interference in which the wave’s amplitude increases |
| Destructive interference | Type of interference in which the wave’s amplitude decreases |
| Standing wave | Wave that does not appear to be moving; occurs at the natural frequency of the material |
| Sonar | The use of sound wave to determine distances |
| Telescopes | A device used to magnify objects that are far away |
| Ultrasonic | Sound above the range of human hearing (20,00 hertz) |
| Doppler effect | Change in sound or light that occurs whenever there is motion between the source and its observer |
| Microscope | A device used to magnify small objects |
| Convex | Lens that is thicker in the middle than at the edges |
| Concave | Lens that is thicker at the ends than in the middle |
| Coherent light | Light found in lasers |
| Photoelectric effect | Process by which light can be used to know electrons out of a metal |
| Radar | use of short-wavelength microwaves to locate objects and monitor speed |
| X rays | Electromagnetic wave in the frequency range just above ultraviolet rays |
| Gamma rays | High-frequency electromagnetic wave released during gamma decay; strongest type of nuclear radiation |
| Ultraviolet rays | Electromagnetic wave in the frequency region just above visible light |
