Physical Science Unit 1 Vocab

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authority

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an accepted source of expert information or advice

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intuition

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the act or faculty of knowing or sensing without the use of rational processes; it involves immediate cognition

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reason

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the capacity for logical, rational, and analytic thought--intelligence

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sensory data

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knowledge obtained through the senses

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hypothesis

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a tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation

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theory

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a set of statements or principles devised to explain a group of facts or a phenomena, especially one that has been repeatedly tested or widely accepted and can be used to make predictions about natural phenomena

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law

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a well-tested theory, so firm as to be unquestioned by science

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model

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a schematic description of a system, theory, or phenomenon that accounts for its known or inferred properties and may be used for further study of its characteristics

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existence

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the fact or state of having actual or real being

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causality

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cause must always precede the effect

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time symmetry

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the laws of the universe do not change with time

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principle of noncontradiction

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of two contradictory propositions, both cannot be true

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Occam's razor

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simpler explanations are more likely to be true than complex ones

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position symmetry

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the laws of the universe are not different at different locations

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interaction

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any of four fundamental ways in which elementary particles and bodies can influence each other

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force

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a push or pull on an object

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strong nuclear interaction

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the interaction between nucleons that gives rise to the strong force

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electromagnetic interaction

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the interaction between nucleons that gives rise to the strong force

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weak interaction

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the interaction between nucleons that gives rise to the weak force

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gravity

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the interaction between anything with mass that gives rise to the gravitational force

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atomic nuclei

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the positively charged central region of an atom, composed of protons and neutrons

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proton

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a composite, strongly interacting particle made up of three quarks. Protons carry a positive electrical charge and is a constituent part of the nucleus of atoms.

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neutron

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a composite, strongly interacting particle made up of three quarks, but which carries no net electrical charge. Neutrons are a constituent part of the nucleus atoms.

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nucleon

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a generic name for either a proton or a neutron.

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quark

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the elementary particles of which protons and neutrons consist. A proton and a neutron each consist of three quarks.

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radioactive

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a term referring to atoms whose nuclei can spontaneously change under the influence of the weak nuclear force.

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electron

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an elementary particle in atoms having a negative charge. Electrons are located outside atomic nuclei.

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element

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a substance composed of atoms that have an identical number of protons in each nucleus. Elements cannot be reduced to simpler substances by normal chemical means.

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atom

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the fundamental unit of an element

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molecule

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a microscopic structure usually made up of more than one atom

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solar system

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the sun and all planets, comets, asteroids and other bodies that orbit about it under the pull of gravity

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Aristotle

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Aristotle's concept of force being necessary to sustain all motion was thought to be true for nearly 2,000 years

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Galileo Galilei

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Galileo understood the law of inertia several decades before Isaac Newton

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state of uniform motion

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The condition of an object when no unbalanced force acts upon it. A state of motion always refers to being at rest or in uniform motion.

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Sir Isaac Newton

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In 1687 he published the book Principia Mathematica the three laws of motion that bear his name

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velocity

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the speed in a particular direction of a moving body

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acceleration

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rate of change of velocity per unit time, or change of velocity divided by the time required for the change

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centripetal

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toward a center

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net force

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the sum of all the forces present on a body

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unbalanced forces

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the portion of the total force that is unopposed by other forces and so will cause an acceleration; an unbalanced force means that the net force is not zero

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mass

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the characteristic of a body which determines how much it accelerates when a force is applied

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weight

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a measure of the force of gravity pulling on an object

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standard kilogram

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the unit of mass, the kilogram (kg), remains the only base unit in the International System of units that is still defined in terms of a physical artifact; the standard was manufactured in 1879l it is sored in an evacuated chamber near Paris

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g

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the symbol representing the acceleration caused by gravity; it is equal to 22 mi/h/s or 32 ft/s/s or 9.8 m/s/s depending on the units

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weight

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the force of gravity on an object

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the law of gravity

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expressed by the mathematical formula F=GmM/d2 that describes the strength of the force of gravity between two objects of mass M and m separated between their centers by the distance d

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gravitational constant

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a number relating the strength of the gravitational force to the masses being attracted and their distance apart

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Henry Cavendish

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British scientist known for his work with hydrogen and his experiment that measured the gravitational force between two masses in order to calculate the density of the Earth

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general theory of relativity

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Albert Einsten's description of gravity that was published in 1915; this theory explains the relationship between the geometry of space and the flow of time in our universe

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Benjamin Franklin

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Franklin was not only renowned as a statesman, but he was also an accomplished scientist.

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Augustin de Coulomb

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Discovered that forces between charged bodies are proportional to the charges on them, and inversely proportional to the square of their distance.

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electric force law

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the mathematical formula F=kqQ/d2 that describes the strength of the force between two objects of charge Q and q separated between their centers by the distance d.

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electric force constant

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a number relating the strength of the electric force to the charges involved and their distance apart

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J. J. Thomson

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Thomson used a gas discharge tube to determine that electricity had mass.

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electron

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the basic negative charge-carrying particle in an atom

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Robert Millikan

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developed a way to measure the charge of individual electrons

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Coulomb

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the unit of measure for charge; it is names after Charles Augustin de Coulomb, formulator of the electric force law; the amount of electric charge possessed by a single electron or a proton is 1.6x10-19 coulombs

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proton

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the basic positive charge-carrying particle in an atom

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neutron

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a neutral particle found in the nuclei of atoms

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insulator

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a material that does not permit electrons to flow through it

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conductor

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a material that allows electrons to flow through it

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electric current

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electric charges flowing through a conductor

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direct current

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a steady flow of electrons in one direction, typically through a wire

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alternating current

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a current of electrons that changes direction of flow

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ferromagnetism

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metal alloys that are attracted to magnets or are capable of being transformed into permanent magnets are called ferromagnetic

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William Gilbert

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proposed that the earth was itself a giant magnet

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field

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physical quantity existing at every point in space; some fields arise from sources and may be thought of as the "influence" of these sources

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field lines

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lines coming from an object representing the strength of the force; the denser the lines, the stronger the force

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domain

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a small section in a magnet where the magnetic force from all the atoms add together

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Earth's poles

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the magnetic pole near Earth's geographic North Pole is actually a south magnetic pole, because it attracts a compass magnet's north pole

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Curie temperature

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the temperature above which a metal is no longer magnetized; the Curie temperature is unique for different types of metals

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electromagnetic induction

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a changing magnetic field produces an electric field at right angles to the magnetic field

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contact force

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the force arising between objects when they touch; contact forces are a repulsion caused by the electromagnetic interaction

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freefall

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the act of always falling under the pure influence of gravity

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centripetal force

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a force sideways to the motion of an object; centripetal forces cause objects to turn toward the center of a circle

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fictitious "force"

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an effect in which the tendency to move in a straight line at a constant speed, by the first law, is interpreted as an (apparent) force; fictitious forces are perceived within, or in association with, accelerating objects

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fluid

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anything that flows; this refers to gases such as air and liquids such as water

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pressure

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the force on an object divided by the area over which the force is applied

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buoyant force

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a force pushing upward on objects immersed in a fluid

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density

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an object's mass divided by its volume

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convection

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circulation in a fluid caused by temperature and density differences

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relativity

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the idea that motion is only defined relative to other objects, which may have their own motion; there is no such thing as an "absolute" motion measured against objects that are absolutely at rest

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inertial frame of reference

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a perspective that is experiencing no acceleration

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non-inertial frame of reference

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a perspective that is undergoing an acceleration

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Galilean relativity

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the notion that a final speed vector can be computed by directly adding all individual velocity vectors together according to the rules of Euclidean geometry

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special theory of relativity

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the theory of how objects in inertial frames of reference behave at high speeds

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Gedanken experiment

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a situation of logic contrived to illustrate a particular effect

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time dilation

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the slowing of a clock as its speed approaches the speed of light as measured by an observer not moving with the clock

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length contraction

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the shortening of an object along its direction of motion as its speed approaches the speed of light, as measured by an observer not moving with the object

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event

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a happening that occurs at a particular point in space and at a definite time

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conserved quantity

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unchanging in time; a quantity is "conserved" if the amount of that quantity does not change in time, even though processes may be changing its form

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atomic mass number

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the total number of protons and neutrons in the nucleus of an atom

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linear momentum

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an object's mass times its velocity; measures the amount of motion in a straight line

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angular momentum

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a quantity that measures the amount of rotational motion an object has

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Emmy Noether

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born in Germany in 1882, the daughter of a math professor; she wanted to follow in the footsteps of her father, but none of the universities of her day would allow a woman to enroll as a student; after auditing courses for two years, she took and passed the entrance exams for the doctoral program; a year later the university where her father taught agreed to accept her as a student in good standing; she received her doctorate in mathematics in 1907; she then taught classes for free under her father's and other professors' names for several years, and finally was granted official status in 1919; in 1933 she fled Germany when the Nazis came to power and came to the United States where she taught at Bryn Mawr and Princeton

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potential energy

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energy that depends on the position of an object or on the positions of an objects constituent parts

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kinetic energy

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the form of energy associated with motion; the kinetic energy of an object in motion is given by KE=1/2 x mass x speed2

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gravitational potential energy

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the energy stored in an object that has the potential to fall; near the surface of the earth, the increase of gravitational potential energy of an object that is lifeted is given by GPE=weight x height

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electrical potential energy

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the form of energy associated with the relative positions of charged objects; objects with opposite charges have maximum electrical potential energy when they are separated by great distance, but objects with the same charge have maximum electrical potential energy when they are separated by the least distance; this is the type of energy stored in a lightening cloud

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work

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the technical name given to the process by which energy is transferred to or from an object by an agent that exerts force on the object and the object moves along the direction of the force

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internal energy

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a name given to energy hidden within matter but manifest by the temperature of the matter, the physical state of the matter (solid, liquid, gas), the chemical composition of the matter (i.e., the kind of energy that might be released by the burning or explosion of a substance, etc.

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thermal energy

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total kinetic energy of random motion of molecules in a material

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perpetual motion machine

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a perpetual motion machine is something that keeps moving forever without any energy being added

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conduction

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the transmission of an electric charge or heat through a conducting medium without perceptible motion of the medium itself

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convection

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the process by which energy is moved from one place to another by being stored in matter as internal energy, then moving the matter from one place to another

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radiation

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the process by which energy is moved from one place to another by being stored in matter as internal energy, then moving the matter from one place to another

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chemical potential energy

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the form of internal energy associated with the physical and chemical states of matter; this is the type of energy stored in a car battery

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elastic potential energy

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the form of internal energy associated with stretching or compressing a material

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nuclear potential energy

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the energy stored in the nucleus of an atom

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rest mass

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mass of an object when it is at rest relative to the observer