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cosmology

answer

the study of the origin, evolution, and behavior of the universe as a whole

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universe

answer

that which contains and subsumes all the laws of nature, and everything subject to those laws; the sum of all that exists physically, including matter, energy, physical laws, space, and time

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astronomy

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the study of the contents of the universe beyond the Earth

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anthropomorphism

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the projection of human attributes onto nonhuman entities such as animals, the planets, or the universe as a whole

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myth

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a narrative intended to explain or justify the beliefs of a people. the term usually suggests a lack of historical and factual basis

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anthropocentrism

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the belief that humans are central to the universe

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experiment

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a controlled trial for the purpose of collecting data about a specific phenomenon

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scientific method

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an investigative approach in which data is gathered, a hypothesis is formulated to explain the data, and further experiments are performed to test the hypothesis

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data

answer

the outcome of a set of measurements from which inferences may be drawn, theories constructed, etc.

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hypothesis

answer

a proposed explanation for an observed phenomenon. in science, a valid hypothesis must be based upon data and must be subject to testing

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relevant

answer

of a scientific hypothesis: directly related to the phenomenon it seeks to explain

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falsifiable

answer

of a scientific hypothesis: leading to the possibility of performing an experiment that would disprove.falsify the hypothesis

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consistent

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of a scientific theory: containing and extending an earlier well-supported theory, ex. general relativity is consistent with Newtonian gravity

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crucial experiment

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an experiment that has the power to decide between two competing theories

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simplicity

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the property of a scientific hypothesis that its proposed explanation must not be unnecessarily complicated

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Occam's Razor

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the principle that when all other things are equal, the simplest explanation is preferred

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predictive power

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the ability of a hypothesis or model to predict unobserved effects. this provides an important means of testing a hypothesis.

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explanatory power

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the ability of a scientific hypothesis to account for known data

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theory

answer

in scientific usage, a hypothesis or related group of hypotheses that have become well established

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law

answer

in scientific usage, a theory that has become particularly well confirmed and well established

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model

answer

a hypothesis or group of related hypotheses that describes and clarifies a natural phenomenon, entity, etc.

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geocentric

answer

taking the Earth to be the center, for example, of the solar system

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mechanics

answer

the science of motion

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force

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that which produces an acceleration

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inertia

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that property of an object which resists changes in its state of motion

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heliocentric

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taking the sun to be the center (of the solar system)

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parallax

answer

the apparent shift in the position of a star due to the changing vantage point of the observer. can be caused by phenomena such as the orbital motion of the earth, or its daily rotation

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retrograde motion

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the apparent reversal in the motion of a planet across the sky relative to the background stars, caused by the Earth passing the planet or being passed by it

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Copernican revolution

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the revolution in thought resulting from the acceptance of the heliocentric model of the solar system

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Copernican principle

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the principle that the Earth is not the center of the universe

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ellipse

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a geometric figure generated by keeping the sum of the distance from two fixed points (the foci) constant

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Kepler's laws

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the three laws of planetary motion discovered by Johannes Kepler

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thought experiment

answer

an experiment that could be performed in principle but might be very difficult in practice, and whose outcome can be predicted by pure logic. often used to develop the consequences of a theory so that more practical phenomena can be predicted and put to actual experimental tests

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Newton's first laws

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the law of motion which states that an object in a state of uniform motion will remain in that state unless acted upon by an external force

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uniform motion

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motion at a constant velocity. the state of rest is a special case of uniform motion

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force

answer

that which produces an acceleration

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acceleration

answer

a change of velocity with respect to time

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Newton's second law

answer

the law of motion which states that the net applied force on an object produces an acceleration in proportion to the mass (F=ma)

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mass

answer

that property of an object which causes it to resist changes in its state of motion; also, that property which generates gravitational attraction

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conservation of momentum

answer

the principle that the linear momentum of a system (in Newtonian mechanics, mass times velocity) remains the same as long as no external force acts

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vector

answer

a mathematical entity that has direction as well as magnitude. important physical quantities represented by vectors include velocity, acceleration, and force. a vector changes whenever either its direction or its magnitude changes

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Newtons third law

answer

for every action, theres an equal and opposite reaction

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universal gravitation

answer

Newtons mathematical formulation of the law of attraction between two masses (Fg = (GMm)/(R^2))

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gravitational constant

answer

a fundemental constant of nature, G, which determines the strength of the gravitational attraction

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weight

answer

the gravitational force experienced by an object. usually refers to the gravitational attraction due to a large object, such as a planet, upon small objects at or near its surface

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radioactive dating

answer

the determining of the age of a sample by the measurement of the ratio of the decay products to the precursor, for one or more radioactive isotopes. radioactive dating is possible because each unstable isotope has a well-defined half-life.

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photon

answer

a boson which is the particle of electromagnetic radiation (light). the photon is also the carrier particle of the electromagnetic force

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nucleon

answer

either of the two fermionic particles (proton and neutron) which form the nuclei of atoms

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isotope

answer

one of the forms in which an element occurs. one isotope differs from another by having a different number of neutrons in its nucleus. the number of protons determines the elemental identity of an atom, but the total number of nucleons affects properties such as radioactivity or stability, the types of nuclear reactions, if any, in which the isotope will participate, and so forth

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nuclear reaction

answer

a reaction that occurs in and may change the nucleus of at least one atom. ex. radioactivity, fission, and fusion

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neutrino

answer

any of three species of very weakly interacting lepton with an extremely small mass

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boson

answer

a class of elementary particles whose spin is an integer multiple of a fundamental quantized value. the major function is to mediate the fundamental forces. ex. photon

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fermion

answer

a class of elementary particles whose spin is a half-integer multiple of a fundamental quantized value. they make up matter. ex. protons, neutrons, electrons, neutrinos. they obey the exclusion principle

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exclusion principle

answer

the property that fermions of the same type that are able to interact with each other cannot simultaneously occupy the same quantum state

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antimatter

answer

particles with certain properties opposite to those of matter. each matter particle has a corresponding antiparticle. the antiparticle has exactly the same mass and electric charge as its partner. when these two particles combine both are annihilated and converted to photons

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strong nuclear force

answer

the fundamental force that binds quarks into hadrons and holds nucleons together in atomic nuclei

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weak nuclear force

answer

the fundamental force that accounts for some particle interactions, such as beta decay, the decay of free neutrons, neutrino interactions, and so forth.

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electromagnetic force

answer

the force between charged particles that accounts for electricity and magnetism. one of the four fundamental forces of nature, it is carried by photons and is responsible for all observed macroscopic forces except for gravitational forces

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gravity

answer

the weakest of the four fundamental forces; that force which creates the mutual attraction of masses

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energy

answer

the capacity to perform work

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work

answer

the exertion of a force to produce a displacement

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potential energy

answer

the energy possessed by something by virtue of its location in a potential field. ex. its position in a gravitational field

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kinetic energy

answer

the energy associated with macroscopic motion. in newtonian mechanics, the kinetic energy = ((1/2)m(v^2))

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thermodynamics

answer

the theory of heat and its relationship to other forms of energy

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heat

answer

a form of energy related to the random motions of particles that make up an object

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temperature

answer

a measure of the avg kinetic energy of random motion of the constituents (like molecules, atoms, or photons) of a system

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conservation of energy

answer

the principle that the total energy of a closed system never changes, but energy is only converted from one form to another

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conservation of matter

answer

the principle that matter is neither created or destroyed

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entropy

answer

a quantitative measure of the disorder of a system. the greater the disorder, the higher the entropy

question

spectrum

answer

the components of emitted radiation, or a collection of waves separated and arranged in the order of some varying characteristic such as wavelength, frequency, mass, or energy

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interference

answer

the interaction of two waves in which their amplitudes are reinforced and/or cancelled

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Doppler effect

answer

the change in frequency of a wave (light, sound, etc.) due to the relative motion of source and reciever

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blueshift

answer

a shift in the frequency of a photon toward higher energy (star moving towards observer)

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redshift

answer

a shift in the frequency of a photon towards lower energy (star moving away from observer)

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lightyear (ly)

answer

a measure of distance equal to that travelled by light in one year

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blackbody

answer

a theoretical object that absorbs 100% of the radiation that hits it. Therefore it reflects no radiation and appears perfectly black.

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black body radiation

answer

a body that doesn't reflect any radiation, but absorbs all light/radiation → can emit radiation for cooling.

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equilibrium

answer

a balance in the rates of opposing processes, such as emission and absorption of photons, creation and destruction of matter, etc.

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luminosity

answer

the total power output of an object in the form of light

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galaxy

answer

a large, gravitationally bound system of stars, star clusters, and interstellar matter

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galaxy cluster

answer

a group of galaxies that are mutually gravitationally bound

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supercluster

answer

a cluster of galaxy clusters

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Karl Popper

answer

author of The Logic of Scientific Discovery. held that science progresses only by falsifiability

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what the greeks knew

answer

that the earth was round, thought the earth was stationary, and believed that theory was more important than observation

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Aristotle

answer

student of plato, believed theres a separation between earthly and heavenly (earthly and heavenly elements), champion of Geocentric model of universe

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Ptolemy

answer

author of Almagest, explained retrograde motion of planets, his system made accurate predictions about the motions of the plantes

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Almagest

answer

Ptolemy's book that refined Aristotles geocentric system

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Ptolemy's model

answer

earth in center, with deferents and epicycles

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epicycle

answer

small circle within deferent that planet revolves in. part of Ptolemy's model

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deferent

answer

major circle of Ptolematic model

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what did ptolemy not believe?

answer

that planets are made of the same elements as the earth

question

ptolemy believed...

answer

that planets move in combos of circles, planets move at a constant speed, and planets move around the earth

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Nicholas Copernicus

answer

author of De Revolutionibus Orbium Coelestrium (Revolutions), who proposed heliocentricism and uniform circular motions

question

why didnt copernicus publish?

answer

he was afraid other scholars would laugh at him

question

Revolutions

answer

written by Copernicus, banned by catholic church

question

what did Copernicus not believe?

answer

that planets all travel at the same speed

question

problems with Copernicus's model

answer

no one had observed parallax of stars, we dont feel the earth move or rotate, it still requires epicycles to accurately match observations of planets

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Platonic solids

answer

ether, fire, air, water, earth

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Kepler's First law

answer

planets travel in elliptical orbits, with the Sun at one focus

question

Kepler's Second law

answer

a line from the Sun to a planet sweeps out equal areas in equal times (planets move faster when theyre closer to the sun)

question

Kepler's Third law

answer

P^2 = a^3

question

astronomical units (AU)

answer

1 AU = the avg distance from the earth to the sun

question

Galileo

answer

author of Starry Messenger

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Pope Urban VIII

answer

early admirer of Galileo's works who first encourage Galileo to publish Dialogue, but then never aided Galileo when Dialogue went under fire by the church

question

Dialogue Concerning Two Chief World Systems

answer

book by Galileo, with characters Salviati (represented Galileo), Simplicio (represented church/Aristotle's followers, also a fool), and Sagredo (represented impartial observer). Written in everyday italian. Was banned by church due to simplicios character, and Galileo stood trial and was forced to stop teaching copernicanism. Galileo had to recant his beliefs

question

Isaac Newton

answer

went to Trinity College, and when he returned home he invented differential and integral calc, developed theory of light and optics, formulated modern dynamics (force, inertia, velocity, acceleration), and began to formulate universal law of gravity. Author of Principia, creater of 3 laws

question

Edmund Halley

answer

prompted Newton to prove and publish that the inverse square law of gravity results in Keplers ellipses (Principia)

question

Principia

answer

book by Newton published due to the urgings of Edmund Halley

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Newton's Universal Law of Gravity

answer

F = (GMm)/(R^2)

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William Herschel

answer

discovered Uranus in 1781

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Adams and Le Verrier

answer

men who predicted the existance of an unseen planet (Neptune) based on Uranus' orbit and Newton's law of gravity

question

Joseph von Fraunhofer

answer

self-taught Bavarian mathematician and optician, discovered in 1814 that the spectrum of the sun contains hundreds of dark lines

question

Gustav Kirchoff

answer

creater of Kirchoff's laws dealing with spectra

question

Kirchoff's First Law

answer

hot opaque objects (solids or dense gases) produce continuous spectra (like a rainbow)

question

Kirchoff's Second Law

answer

hot thin gases produce emission line spectra (neon signs)

question

Kirchoff's Third Law

answer

cool thin gases between a hot opaque object and the observer produce absorption line spectra (stars)

question

continuous spectrum

answer

a series of colors formed when a beam of white light is dispersed so that the component light waves are arranged in the order of their wavelengths (without any black lines between colors)

question

absorption line spectrum

answer

A spectrum that is continuous except for dark lines that appear due to material (usually cool gas) that absorbs specific wavelengths of light

question

emission line spectrum

answer

the bands of color shown by a specific element when electric current is passed through it and then the emitted light is separated through a prism

question

spectral lines

answer

unique to each element, and can be used to measure chemical composition, temp, density, magnetic fields, and motion towards or away from an observer

question

temperature

answer

a measure of the speed of random internal motions of the molecules in a substance

question

Max Planck

answer

solved the blackbody problem by accepting that energy came in discrete amounts called quanta. won nobel prize for this

question

Plack's formula

answer

E = hv (Energy = Plancks constant x frequency)

question

Stefan-Boltzmann Law

answer

Energy emitted is proportional to T^4. Hotter objects emit more total energy

question

blackbody spectra

answer

aka continuous spectra aka thermal spectra. spectra cause by electrons in dense objects randomly vibrating due to hear.

question

why don't I fall through the floor?

answer

because the electrons in my shoes repel the electrons in the floor

question

absorption

answer

when electrons absorb energy, thus transferring to a higher energy level

question

emission

answer

when electrons transfer to a lower energy level, giving off energy (photons) in the process

question

inverse square law of light

answer

b = L/(4pi(R^2)). brightness = luminosity/(4pi)(distance^2). explains why light gets duller but more widespread as you move outward

question

what makes one element different from another?

answer

the number of protons they have/their atomic number

question

chemical reactions

answer

reactions between the electrons of atoms. the elements themselves remain unchanged

question

fission

answer

type of nuclear reaction that occurs when large nuclei split into smaller ones, releasing energy. can happen spontaneously. ex. atomic bombs

question

fusion

answer

type of nuclear reaction that occurs when small nuclei fuse into larger ones, releasing energy. requires high temps and densities. ex. hydrogen bombs

question

age of the eart

answer

worked on by James Ussher, Darwin, Kelvin, Hans Bethe (whose work led to an age estimate of the sun for 5 billion years), and radioactive dating, which dated the earth at 4.6 billion years

question

induction

answer

reasoning from detailed facts to general principles

question

deduction

answer

reasoning from the general to the specific (or from cause to effect)

question

earthly elements

answer

earth, water, air, fire

question

heavenly elements

answer

quintessence, ether

question

Aristotle's beliefs

answer

that objects move linearly with respect to the center of the universe, believed that force causes deviation in natural motion, believed in primacy of circular motion, believed that the heavens (not earth) moved, and described universe in terms of natural laws

question

primacy of circular motion

answer

continuous circular motion of the heavens

question

impetus

answer

travelling, generalized force

question

Galileo

answer

famous because he was the first to use the telescope to see celestial things, discovered Jupiter's moons, and reasoned that all objects fall at the same rate in a vacuum, discovered the sun had spots

question

Copernican beliefs

answer

believed each planet has their own unique velocity, believed earth was not center of universe

question

atom models

answer

plum pudding model--> Rutherford experiment--> solar system nuclear model-->modern model of atom

question

half-life

answer

the time required for half a sample of a radioactive element to decay. Its a means of dating radioactive samples

question

cosmic rays

answer

high energy rays impinging upon earth from space

question

quantum mechanics

answer

a system of physical laws that governs the behavior of the elementary particles, nuclei, and atoms

question

speed of light

answer

c = wavelength x frequency

question

radiation

answer

emission of energy from an object often in the form of a wave

question

Balmer and Bunsen

answer

pointed an emission line spectra instrument at the stars to measure their composition, thereby discovering that stars are made of elements, not ether

question

Planck's Distasteful Idea

answer

energy is not continuous, it comes in "packets"

question

if something is 3 light years away...

answer

then the light left its source 3 years ago

question

ion

answer

An atom that has gained or lost electrons, thus acquiring a charge.

question

helium and hydrogen

answer

most abundant elements

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