Science And The Modern World Test 1 Flash Cards

Front 1

Epicycle

Back 1

a small circle the center of which moves around a point on the circumference of a
larger one

Front 2

Eccentric

Back 2

circle around a point that is off center where epicycles revolve.
The center of the epicycle moves around on a larger circle which is called an eccentric

Front 3

Equant

Back 3

circle around a point that is off center where epicycles revolve.

Front 4

Homocentric Spheres

Back 4

Think of this as 2 crystal spheres where the smaller one is inside the larger one but is on the same axis. If we counter rotate the outer sphere relative to the inner one then it makes a dot on the inner sphere’s equator looked fixed. However if the axis is offset when counter rotation occurs then the dot will exhibit a figure 8 motion. If this figure 8 is superimposed on the two sphere model then it could explain retrograde motion.

Front 5

Eudoxus

Back 5

was first to propose the homocentric spheres concept.

Front 6

Heliocentric

Back 6

Sun-centered. Heliocentric theories placed the sun at the center of the universe.

Front 7

Retrograde Motion

Back 7

is motion in the direction opposite to the movement of something else. This was observed when wandering planets seemed to slow down then go backwards in the night sky and then resume normal motion with regards to the sphere of the stars.

Front 8

Diurnal Motion

Back 8

An astronomical term referring to the apparent daily motion of stars around the Earth, or more precisely around the two celestial poles.

Front 9

Geocentric

Back 9

Earth-centered. Geocentric theories placed the Earth at the center of the universe.

Front 10

Two-Sphere Model

Back 10

is a geocentric model that divides the cosmos into two regions. A spherical Earth, central and motionless (sublunar realm) and a spherical heavenly realm centered on the Earth, which may contain multiple rotating spheres made of aether. This was used to explain the suns movement/ location in so that it rotates around the outside sphere.

Front 11

Aristarchus

Back 11

Greek astronomer that presented the first known heliocentric model of the universe.

Front 12

Anaximander

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a presocratic philosopher; said that the basic “stuff” of the universe is something indefinite/unlimited called “apeiron”.

Front 13

Summer Solstice

Back 13

When the axis of the earth tilts toward the sun we have summer in the northern hemisphere around June 20th. At this point the sun is at its highest point in the sky at noon.

Front 14

Vernal/Autumnal Equinoxes

Back 14

occurs twice a year, when the tilt of the Earth’s's axis is inclined neither away from nor towards the Sun, the center of the Sun being in the same plane as the
Earth's equator. vernal=spring autumnal=fall

Front 15

Antiperistasis

Back 15

An attempt to explain why an object when thrown continues to travel straight and not immediately fall down to the ground as earth was thought to behave. Air moves from the front of the object to the back of it and as a result pushes the object.

Front 16

Principle of Sufficient Reason

Back 16

States that anything that happens does so for a reason: no state of affairs can obtain, and no statement can be true unless there is sufficient reason why it should not be otherwise. Used by Leibniz when arguing with Newton.

Front 17

Natural Motions

Back 17

the falling of objects and substances have a natural place or level such as air above, water below and they proceed in the most direct way, along straight vertical paths to their natural places. Air and fire go straight up to the heavens away from the center of the cosmos. Water and Earth fall straight down to the center of the Earth. Aether moves in circles.

Front 18

Violent Motions

Back 18

any motion other than the natural motions explained above. For example picking up a rock involves violent motion.

Front 19

Impetus

Back 19

“Power to move.” Thought to gradually dissipate over time, idea was used in Aristotelian physics to explain the continued motion of an object after contact is lost with the original projector.

Front 20

Heraclides of Pontus

Back 20

best known for proposing the theory that the earth revolves on an axis from west to east once every 24 hours, which explains the motion of the stars.

Front 21

Plenum

Back 21

A space completely filled with matter

Front 22

Horror Vacui

Back 22

theory first proposed Aristotle that stated that nature abhors a vacuum and therefore would be trying to suck in gas or liquid to fill an empty space if there is one.

Front 23

Giordano Bruno

Back 23

His cosmological theories went beyond the Copernican model in proposing the sun was essentially a star, and moreover that the universe contained an infinite number of
inhabited worlds populated by other beings. He was burned at the stake for heresy. And helped Copernican model be more acceptable to religious people because a very large, possible infinite, universe would reflect an infinite god.

Front 24

Neoplatonism

Back 24

“Christianized” version of Plato’s philosophy concerning a wide variety of objectively existing, nonphysical, eternal “forms”; he focused on truth and beauty, but above all
Good (symbolized as the sun-- the source of life) and Good is truth and knowledge. Neoplatonists replace Good with the Christian God, so that He was the highest form.

Front 25

Stellar Parallax

Back 25

a parallax is the apparent shift in position of stellar objects due to your motion

Front 26

Tycho Brahe

Back 26

(1546-1601) blends copernican and ptolemaic astronomical systems; was a respected astronomer known for accurately collecting empirical data.

Front 27

Tychonic model

Back 27

blend ptolemaic and copernican models-- the earth is the center of the universe, and the moon and sun revolve around the earth; the planets revolve around the sun.

Front 28

Kepler

Back 28

1571-1630 finally developed a system that was simpler, but accurate in explanation and prediction; he worked for Tycho Brahe and was highly influenced by him, especially in collecting data; broke perfect circle and uniform motion laws; designed elliptical orbits with varying speeds.

Front 29

Kepler’s Laws: 1st law of planetary motion

Back 29

planets orbit the sun in elliptical orbits, with the sun
occupying 1 of the foci in the ellipse

Front 30

2nd Law of Planetary Motion:

Back 30

For any equal time period, the movement of the planet covers an equal area-- in an ellipse, that kind of movement results in varying speeds

Front 31

Kepler's Laws: 3rd Law of Planetary Motion

Back 31

The ratio of a planet’s period (T) squared to its semi major axis (a) cubed is constant. i.e (T1/T2)^2 = (a1/a2)^3 where T is the planet’s period and a is its semi major axis

Front 32

Galileo

Back 32

(1564-1642) Italian physicist, mathematician, astronomer and philosopher who was known for his championing of heliocentrism. Galileo stood correct on many of his observations but was wrong in denying the moon’s cause of the tides and Kepler’s belief in the elliptical nature of planetary orbits.

Front 33

Law of Inertia

Back 33

An object in motion remains in motion in a straight line, and an object at rest remains at rest unless acted upon by an outside force.

Front 34

Isaac Newton

Back 34

(1642-1727) English physicist, mathematician, astronomer, etc. who is arguably the most prominent scientist who ever lived. Newton lays the foundation for classical mechanics, the law of universal gravitation, the three laws of motion and most notably his development of calculus. Newton is responsible for removing the final doubts of heliocentrism.

Front 35

Relationism

Back 35

The idea that space exists only as a relation between objects, and has no resistance apart from the existence of these objects. Motion exists only as a relation between these objects.

Front 36

Substantivalism (about space)

Back 36

Opposing relationism, substantivalism states that space is, in fact, a real entity and the nature of our reality can not solely be described using talk regarding relations between objects. One is forced to define reference frames in space to understand the dynamics of our universe.

Front 37

Identity of Indistinguishables

Back 37

The prospect of a particle being indistinguishable arises from the uncertainty of its position as well as its lack of uniqueness in relation to identical particles surrounding it.

In this sense, you can not paint two electrons in close proximity as red and blue and call the Electron A and Electron B because you can’t say which electron is which; after all, even God doesn’t know which electron is which. In this sense, the two particles are indistinguishable.

Front 38

Cosmology

Back 38

The study of the nature of the universe as a whole. Cosmologists seek to understand the origin, evolution, structure and fate of the Universe as we as its governing physical laws.

Front 39

Interference Pattern

Back 39

the pattern created by different waves interacting--waves can combine
to form larger waves or cancel each other out to form a ‘valley’; the pattern would be alternating
bands of light and dark (on photographic paper). Bright fringes occur in areas of constructive interference [waves in phase with one another] and dark fringes occur in areas of destructive interference [waves 180 degrees out of phase]).

Front 40

Ptolemy

Back 40

(90-168AD) Ptolemy was a Greek-Roman citizen of Egypt whose noteworthy contribution to astronomy is the Ptolemaic Model in which planets travel in epicycles, the centers of which orbit in uniform motion around the Earth.

Front 41

Twin Paradox

Back 41

If one of a set of twins travels near the speed of light to some star 15 light-years away and the other twin remains on Earth, when the astronaut twin returns, she will be nearly as young as when she left, whereas her twin will have aged 30 years.

Front 42

Two-slit experiment

Back 42

When a monochromatic source of light travels through two slits separated a given distance from one another, the two emerging light beams will converge upon the wall behind the grating. Depending on whether the rays are in phase or out of phase, they will either constructively interfere to form bright fringes or destructively interfere to form dark fringes. This is known as an interference pattern and extends to beams of particles (electron beams) as well as traditional light (photons).

Front 43

EPR ‘paradox’

Back 43

(This is my best attempt at explaining the paradox -- I don’t completely understand it myself) Paradox against QM posited by Albert Einstein, Boris Podolsky and
Nathan Rosen. If a particle is coupled to another particle (entaglement) and both particles arrive at detectors located in two opposite directions from the particle-source, their positions and momentum can be thought of as correlated. Based on Heisenberg’s Uncertainty principle, if the position of one particle is well known, the momentum is uncertain, but since the two particles are entangled, the second particle’s momentum must also retain an equal sense of uncertainty. The EPR paper states that the particles need to have hidden parameters (hidden variables) to explain why the second particle knows that it should have uncertainty in momentum. Since there is no room for hidden parameters in the formalism of QM, the whole theory must be incomplete.

Front 44

Bell’s Theorem

Back 44

No physical theory of local hidden variables can reproduce all of the predictions of quantum mechanics. (A local hidden variable theory is one in which distant events are assumed to have no instantaneous (or at least faster-than-light) effect on local ones.)

Front 45

Hidden-Variable Theory

Back 45

Historically, in physics, hidden variable theories were espoused by some physicists who argued that quantum mechanics is incomplete. These theories argue against the orthodox interpretation of quantum mechanics, which is the Copenhagen Interpretation. Albert Einstein, the most famous proponent of hidden variables, famously insisted that, "I am convinced God does not play dice", but whether he objected to the statistical nature of quantum mechanics is disputed.

Front 46

Copenhagen Interpretation

Back 46

the standard interpretation of quantum theory, that it reflects reality, and the fact that we can’t know what the outcome of a quantum event will be before measurement takes place (before the ‘wave collapse’) is not because we can’t know, but because quantum entities lack definite attributes before the measurement takes place.

Front 47

Black-Body Problem

Back 47

The black-body is an idealized physical entity that absorbs all
electromagnetic radiation incident upon it.

Front 48

Instrumentalism

Back 48

an adequate theory is one that predicts and explains; however, whether that theory reflects or models reality is not important.

Front 49

Polarizer ‘Paradox’

Back 49

polarization measurements are actually changing the state of photons.

Front 50

Photoelectric Effect

Back 50

When light is shone on metal, the surface may become positively charged. This is because electrons gain energy from the light waves, and are able to leave the metal's surface.

Front 51

Determinism/ Indeterminism

Back 51

classical physics is deterministic; the physical state of the world is determined by a description of all objects’ mass/speed/location...so in principle, if you know state
at time1, you can figure out what the state will be at time-n.

Front 52

Atomic Spectra

Back 52

When gases are heated in particular ways they emit light at selected frequencies, each has its own set of frequencies. The frequency at which a photon is emitted/absorbed corresponds to the energy between atomic levels/orbitals.

Front 53

Wave Superposition

Back 53

In QM, the existence of a variable (let’s say position) is determined by a probability density function which results from a superposition of all possible wave functions in the system. In a coin flip example, the resulting wave function can be thought of the wave function for heads and the wave function for tails -- in this case, the two wave functions are added together to define the underlying system.

Front 54

Uncertainty Principle

Back 54

It turns out that any measurement of the position of a quantum system ‘blurs’ the momentum. Any measurement of the momentum blurs the position.

Front 55

Complementarity

Back 55

According to Neils Bohr, we can describe the quantum world in terms of the position of things or in terms of the momenta of things. We can not meaningfully describe the quantum world in both respects at the same time. Bohr calls the two descriptions ‘complementary’ in that each captures an aspect of quantum reality, but neither captures all of quantum reality

Front 56

Delayed-Choice Experiment:

Back 56

If we think of a stream of photons travelling around a celestial body, the photons can go either to the left of it or to the right of it (in two dimensions). However, if we decide to detect the photon at either the right or the left of the planet, the photon’s wave function would have to collapse as either left or right at that moment in time, but this is a delayed choice since the photon should’ve had to decide left or right when it exited its initial source. (I think this is what he was going for)

Front 57

Schrodinger’s Cat Experiment

Back 57

A thought experiment that shows how bizarre quantum mechanics can be in reality. Place a cat in a box containing a radioactive atom and a vial of cyanide that decomposes along with the radioactive atom. Once the cyanide is released from the vial and kills the cat, the cat is neither considered dead or alive until it is observed to be dead or alive. It is essentially stuck in a state of superposition.

Front 58

Measurement Problem

Back 58

An electron acts like a wave if we don’t check which hole it went through; however, it acts like a particle if we do check it.

Front 59

Thought Experiment

Back 59

considers some hypothesis, theory or principle for the purpose of thinking through its consequences. Given the structure of the experiment, it may or may not be possible to actually perform it, and, in the case that it is possible for it to be performed, there need be no intention of any kind to actually perform the experiment in question. The common goal of a thought experiment is to explore the potential consequences of the principle in question.

Front 60

Induction

Back 60

even if all premises are true, it is still possible for a conclusion to be wrong; goes from specific reasoning to general.

Front 61

Worldview

Back 61

a system of interconnected beliefs; an intertwined, interrelated, interconnected system of beliefs.

Front 62

Deduction

Back 62

goes with discomfirmation reasoning; general to specific; the facts add up to a guaranteed conclusion -- true premises guarantee true conclusion

Front 63

Mechanism

Back 63

teleological explanation that isn’t given in terms of goals, purposes, or functions-- Why did the rock fall? gravity --it’s the opposite of teleological explanation.

Front 64

Determinism

Back 64

a philosophy stating that for everything that happens there are conditions such that, given them, nothing else could happen.

Front 65

Quine-Duhem Thesis

Back 65

beliefs are not built separately but together-- they are a body of beliefs; our beliefs then face the “tribunal of experience” together. When you test a main belief or hypothesis, there are auxiliary hypotheses being tested as well.

Front 66

Popper

Back 66

(1900’s) falsificationist approach; a theory is better if it withstands attempts to falsify
it rather rather than trying to confirm it; he also said the riskier the theory the more scientific it is

Front 67

Falsificationism

Back 67

Popper developed this theory - good scientific theories should be designed so that they can withstand verification processes-- Newton’s theory of gravitation and Einstein’s theory pass the test

Front 68

Indeterminism

Back 68

The concept that events are not caused by prior events. It is the opposite of determinism and related to chance.