Flashcards: Science Final Vocab
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Created by:
dannykrause2121 on June 6, 2011
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Terms | Definitions |
|---|---|
 Precision | Describes how closely measurements are to each other and how carefully the measurements were made |
| Accuracy | Compares a measurement to the real or accepted value |
| Volume | Amount of space occupied by an object. |
| Mass | amount of matter in an object |
| Density | mass per unit volume of a material |
| Dependent Variable | Variable whose value changes as a result of changes in other variables |
| Scientific Law | standard used to compare the results of the experiment |
| Variable | A factor that can cause a change in the results of an experiment |
| Technology | the application of science to help people |
| Constant | a factor in an experiment that does not change |
| Model | represents an idea, event, or object to help people observe or test it |
| Independent Variable | the variable you change to see how it affects another variable |
| Bias | occurs when a scientist's expectations change how the results are viewed |
| Scientific Method | organized set of investigation procedures that can include stating a problem, forming a hypothesis, researching and gathering information, testing a hypothesis, analyzing data, and drawing conclusions |
| Theory | explanation of things or events that is based on knowledge gained from many observations and investigations |
| Volume | amount of space occupied by an object |
| Hypothesis | educated guess using what you know and what you observe |
| Experiment | organized procedure for testing a hypothesis; tests the effect of one thing on another under controlled conditions |
| Constant | in an experiment, a variable that does not change when other variables change |
| Graph | visual display of information or data that can provide a quick way to communicate a lot of information and allow scientists to observe patterns |
| Ratio | a comparison of two numbers by division |
| Air Resistance | force that opposes the motion of objects that move through the air |
| Balanced Forces | forces on a object that combine to give a zero net force and do not change the motion of the object |
| Friction | A force that opposes the sliding motion between objects that are in contact |
| Net Force | sum of the forces that are acting on an object |
| Force | strength or energy as an attribute of physical action or movement |
| Static Friction | between 2 solid objects that are not moving relative to each other. |
| Unbalanced Forces | always cause a change in motion they are not equal and opposite. |
| Vector | a quantity having direction as well as magnitude. As determining the position in space relative to another. |
| Centripetal Force | a force that acts on an object that is moving in a circular path and is directed toward the center around which the object is moving. |
| First law of motion | every object remains in a state of rest or motion unless acted upon by an external, unbalanced force |
| Second law of motion | a body of mass (m) subject to a force (F) undergoes an acceleration (a) that has the same direction as the force and a magnitude that is directly proportional to the force and inversely proportional to the mass. F=ma |
| Third law of motion | every action has an equal, opposite reaction. |
| Law of Conservation of Momentum | states that if a group of objects exerts forces only on each other, then the total momentum of the objects doesn't change. You can't loose momentum, it has to go somewhere. Ex-If a snowball gets bigger rolling down a hill then it gains more momentum, if a thing gets smaller so it has less mass then it has to spin faster so it has the same total momentum. |
| Centripetal Acceleration | the rate of the change in velocity when an object is moving in an arc |
| Inertia | the resistance of any physical object to a change in its state of motion or at rest. Classical- is the tendency of an object to resist a change in motion. |
| Speed | distance an object travels per unit of time. s=d/t |
| Weight | gravitational force exerted on an object |
| Velocity | the speed and direction of a moving object |
| Momentum | property of a moving object that equals its mass times its velocity. m•v |
| Sliding Friction | frictional force that opposed the motion of two surfaces sliding past each other |
| Instantaneous Speed | speed of an object at a given point in time; is constant for an object moving with constant speed, and changes with time for an object that is slowing down or speeding up |
| Gravity | attractive force between two objects that depends on the masses of the objects and the distance between them |
| Displacement | distance and direction of an object's change in position from the starting point |
| Average Speed | total distance an object travels divided by the total time it takes to travel that distance |
| Acceleration | rate of change of velocity; can be calculated by dividing the change in velocity by the time it takes the change to occur |
| Orbit | curved path of one object, such as the Moon, around another object, such as the Earth. |
| Sphere | three-dimensional, round object whose surface is the same distance from the center in all directions |
| Ellipse | elongated, closed curve with two foci; shape of Earth's orbit around the Sun. |
| Ecliptic | yearly path of Earth around the Sun; also, the Sun's apparent path through the zodiac |
| Earth | third planet from the Sun; the only planet know to support life and to have water on it's surface as a gas, liquid, and a solid. |
| Equinox | occurs twice yearly (March and September) when the Sun is directly above Earth's equator and the number of daylight hours equals the number of nighttime hours worldwide |
| Extrasolar Planet | planet in orbit around another star |
| Extraterrestrial life | life on other worlds |
| Big Bang Theory | the theory that the universe started with a big bang, or explosion, and has been expanding ever since |
| Constellation | star pattern that appears to form images, is used by astronomers to locate and name stars and ofter is named for a mythological figure |
| Dark Energy | energy that might be causing accelerated expansion of the universe |
| Dark Matter | unseen mass that adds to the gravity of a galaxy, but cannot be detected or seen. |
| Asteroid | rocky solar system objects of widely varying size usually found between the orbits of Mars and Jupiter in an area called the asteroid belt |
| Astronomical Unit | about 150 million km, which equals the average distance from Earth to the Sun; used to measure distances within the solar system |
| Comet | mass of dust, rock particles, frozen water, methane and ammonia that travels through space and develops a bright, distincitve tail of light as it approaches the Sun and is pushed on by the solar wind |
| Galaxy | large group of stars, gas, and dust held together by gravity; most commonly can be elliptical, spiral and irregular |
| Geocentric Model | Earth-centered model of the solar system |
| Heliocentric Model | Sun-centered model of the solar system |
| Light year | distance light travels in one year-about 9.5 trillion km |
| Giant | late stage in a star's life cycle that occurs when its hydrogen fuel is depleted, its core contracts, and its outer layers expand and cool |
| Maria | relatively flat, dark-colored regions on the Moon's surface |
| Main Sequence | section of the H-R diagram that is plotted from the upper left to the lower right and contains 90 percent of all known stars |
| Milky Way | our spiral shaped galaxy, which contains the solar system and about 400 billion stars including the Sun, and measures about 100,000 light-years across |
| Moon Phase | changing appearance of the Moon as viewed from Earth, depending on the relative positions of the Sun, the Moon, Earth, and the observer. |
| Lunar Eclipse | occurs during the full moon, when the moon enters Earth's umbra and Earth casts a curved shadow on the Moon's surface |
| Meteoroid | rocky solar system object formed from pieces of comets and asteroids |
| Planet | any of the celestial bodies (other than comets or satellites) that revolve around the sun in the solar system |
| Regolith | layer of debris on the Moon's surface formed by the accumulation of meteoric material |
| Revolution | movement of the Earth in its orbit around the Sun; used to measure time in years |
| Rotation | Spinning of Earth on its axis; used to measure time in days |
| Solar Eclipse | occurs during new moon, when the Moon passes directly between the Sun and Earth, casting a shadow on part of Earth |
| Solstice | occurs twice yearly (June and December) when the Sun reaches its greatest distance north or south of the equator. |
| Tide | rise and fall in Earth's sea level, caused by a giant wave formed by the gravitational pull of the Sun and Moon |
| Time Zone | 15º wide area on Earth's surface in which the time is the same |
| Solar Mass | the quantity equal to the mass of the Sun |
| White Dwarf | giant star that has lost its outer layers, leaving behind a hot, dense core that continues to contract under gravity |
| Radio Telescope | telescope that collects and magnifies radio waves |
| Reflection Telescope | optical instrument that uses a concave mirror to collect light and a lens to magnify an image |
| Refracting Telescope | optical instrument that uses double convex lenses to collect light and magnify an image |
| Chemical Formula | chemical shorthand that uses symbols to tell what elements are in a compound and their ratios |
| Ion | charged particles that has either more or fewer electrons than protons |
| Periodic Table | organized list of all known elements, that are arranged by increasing atomic number and by changes in chemical and physical properties |
| Electron Dot Diagram | uses the symbol for an element and dots representing the number of electrons in the elements outer energy level |
| Amplitude | maximum distance a wave causes the particles in a medium to move from the rest position |
| Compressional Wave | a wave for which the matter in the medium moves back and forth along the direction that the wave travels |
| Concave Lens | a lens taht is thicker at the edges than in the middle; causes light rays to diverge and forms reduced, upright, virtual images; usually used in combination with other lenses. |
| Concave Mirror | a reflective surface that curves inward and can magnify objects or create beams of light. |
| Convex Lens | a lens that is thicker in the middle than at the edges and can form a real or virtual images |
| Convex Mirror | a reflective surface that curves outward and forms a reduced upright, virtual images |
| Crest | the highest points on transverse wave |
| Decibel | unit for sound intensity; abbreviated dB |
| Diffraction | the bending of waves around an obstacle; can also occur when waves pass through a narrow opening |
| Doppler effect | change in pitch or frequency that occurs when a source of a sound is moving relative to a listener |
| Electromagnetic Waves | waves created by vibrating electric charges, can travel through a vacuum or through matter, and have a wide variety of frequencies and wavelengths |
| Electromagnetic Spectrum | arrangement of electromagnetic radiation--including radio waves, visible light from the Sun, gamma rays, X rays, ultraviolet waves, infrared waves, and microwaves--according to their wavelengths |
| Frequency | the number of wavelengths that pass a fixed point each second; expressed in hertz (Hz) |
| Loudness | human perception of sound intensity |
| Interference | occurs when two or more waves overlap and combine to form a new wave |
| Index of Refraction | property of a material indicating how much light slows down when traveling in the material |
| Intensity | amount of energy that flows through a certain area in a specific amount of time |
| Medium | matter in which a wave travels |
| Microwaves | radio waves with wavelengths of between about 1 m and 1mm |
| Opaque | material that absorbs or reflects all light and does not transmit any light |
| Plane Mirror | flat, smooth mirror that reflects light to form upright, virtual images |
| Pigment | colored material that is used to change the color of other substances |
| Period | the amount of time it takes one wavelength to pass a fixed point; expressed in seconds. Also, horizontal row in the periodic table |
| Pitch | how high or low a sound seems; related to the frequency of the sound waves |
| Quarks | particles of matter that make up protons and neutrons |
| Radio Waves | electromagnetic waves with wavelengths longer than about 1mm, used for communications |
| Rarefaction | the least dense regions of a compressional wave |
| Refraction | the bending of a wave as it changes speed in moving from one medium to another. |
| Resonance | the process by which an object is made to vibrate by absorbing energy at its natural frequencies |
| Standing wave | a wave pattern that forms when waves or equal wavelength and amplitude, but traveling in opposite directions, continuously interfere with each other; has points called nodes that do not move |
| Speed of light | 299,792,458 meters per second. This speed is approximately 186,282 miles per second. It is the maximum speed at which all energy, matter, and information in the universe can travel. |
| Transverse Wave | wave for which the matter in the medium moves back and forth at right angles to teh direction the wave travels; has crests and troughs |
| Trough | the lowest points on a transverse wave |
| Translucent | material that transmits some light but not enough to see objects clearly through it |
| Transparent | material that transmits almost all the light striking it so that objects can be clearly seen through it |
| Infrared Waves | electromagnetic waves that have a wavelength between about 1 mm and 750 billionths of a meter |
| Gamma Ray | electromagnetic wave with no mass and no charge that travels at the speed of light and is usually emitted with alpha or beta particles from a decaying atomic nucleus; has a wavelength less than about ten trillionths of a meter |
| Visible Light | electromagnetic waves with wavelengths of 750 to 400 billionths of a meter that can be detected by human eyes |
| Wave | a repeating disturbance or movement that transfers energy through matter or space |
| Wavelength | distance between one point on a wave and teh nearest point just like it |
| Ultraviolet Waves | electromagnetic waves with wavelengths between about 400 billionths and 10 billionths of a meter |
| X rays | electromagnetic waves with wavelengths between about 10 billionths of a meter and 10 trillionths of a meter, that are often used for medical imaging. |
| Chemical Change | change of one substance into a new substance |
| Chemical Property | any characteristic of a substance, such as flammability that indicates whether it can undergo a certain chemical change |
| Colloid | heterogeneous mixture whose particles never settle |
| Compound | substance formed from two or more elements in which the exact combination and proportion of elements is always the same |
| Chemical Reaction | process in which one or more substances are changed into new substances |
| Chemical Equation | shorthand method to describe chemical reactions using chemical formulas and other symbols |
| Chemical Bond | force that holds atoms together in a compound |
| Catalyst | substance that speeds up a chemical reaction without being permanently changed itself |
| Covalent Bond | attraction formed between atoms when they share electrons |
| Distillation | process that can separate two substances in a mixture by evaporating a liquid and re-condensing its vapor |
| Element | substance with atoms that are all alike |
| Electron | particles surrounding the center of an atom with a charge of 1- |
| Electron Cloud | area around the nucleus of an atom where the atom's electrons are most likely to be found |
| Electron Dot Diagram | uses the symbol for an element and dots representing the number of electrons in the element's outer energy level |
| Exothermic reaction | chemical reaction in which energy is primarily given off in the form of heat |
| Endothermic reaction | chemical reaction that requires hear energy in order to proceed |
| Base | any substance that forms hydroxide ions, OH-, in a water solution |
| Acid | any substance that produces hydrogen ions, H+, in a water solution |
| Atom | the smallest particle of an element that still retains the properties of the element |
| Atomic Number | number of protons in an atom's nucleus |
| Average Atomic Mass | weighted-average mass of the mixture of an element's isotopes |
| Hydrate | compound that has water chemically attached to its ions and written into its chemical formula |
| Mass Number | sum of the number of protons and neutrons in an atom's nucleus |
| Neutron | neutral particle, composed of quarks, inside the nucleus of an atom |
| Molecule | a neutral particle that forms as a result of electron sharing |
| Nonpolar Molecule | molecule that shares electrons equally and does not have oppositely charged ends |
| Group | vertical column in the periodic table |
| Decomposition reaction | chemical reaction in which one substance breaks down into two or more substances |
| Ionic Bond | attraction formed between oppositely charged ions in an ionic compound |
| Isotope | atoms of the same element that have different numbers of neutrons |
| Law of Conservation of Mass | states that the mass of all substances present before a chemical change equals the mass of all the substances remaining after the change |
| Balanced chemical equation | chemical equation with the same number of atoms of each element on both sides of the equation |
| Double displacement reaction | chemical reaction that produces a precipitate, water, or a gas when two ionic compounds in a solution are combined |
| Homogeneous Mixture | solid, liquid, or gas that contains two or more substances blended evenly throughout |
| Heterogeneous Mixture | mixture, such as mixed nuts, in which different materials are unevenly distributed and are easily identified |
| Oxidation Number | positive or negative number that indicates how many electrons an atom has gained, lost, or shared to become stable |
| Binary Compound | compound that is composed of two elements |
| Nucleus | positively charged center of an atom that contains protons and neutrons and is surrounded by a cloud of electrons |
| Period | horizontal row in the periodic table |
| Periodic Table | organized list of all known elements that are arranged by increasing atomic number and by changes in chemical and physical properties |
| Physical Change | any change in size, shape, or state of matter in which the identity of the substance stays the same |
| Physical Property | any characteristic of a material, such as size or shape, that you can observe or attempt to observe without changing the identity of the material |
| Proton | particle, composed of quarks, inside the nucleus of an atom that has a charge of 1+ |
| Polar Molecule | molecule with a slightly positive end and a slightly negative end as a result of electrons being shared unequally |
| pH | a measure of the concentration of hydronium ions in a solution using a scale ranging 0 to 14, with 0 being the most acidic and 14 being the most basic |
| Product | in a chemical reaction, the new substance that is formed |
| Polyatomic Ion | positively or negatively charged, covalently bonded group of atoms |
| Reactant | in a chemical reaction, the substance that reacts |
| Single displacement reaction | chemical reaction in which one element replaces another element in a compound |
| Solution | homogeneous mixture that remains constantly and uniformly mixed and has particles that are so small they cannot be seen with a microscope |
| Substance | element or compound that cannot be broken down into simpler components and maintain the properties of the original substance |
| Suspension | heterogeneous mixture containing a liquid in which visible particles settle |
| Synthesis Reaction | chemical reaction in which two or more substances combine to form a different substance |
| Tyndall Effect | scattering of a light beam as it passes through a colloid |
| Indicator | organic compound that changes color in acids and bases |