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91 Cards in this Set
- Front
- Back
What is the ptolemaic model? |
Earth centered model of planetary motion created by Ptolemy |
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Why was Ptolemy important to science? |
Created a solar system model that made accurate predictions of planetary positions. |
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How did the Ptolemaic model explain apparent retrograde motion? |
Planets moved along small circles that moved on larger circles around the earth. |
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Comet |
Small icy object orbiting the stars |
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Galaxy |
Great island of starts held together by gravity orbiting a common center |
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Supercluster |
Largest structures in the universe. |
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Astronomical unit |
Average distance of Earth from the sun. 150million km |
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Light year |
Distance light can travel in a year |
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How must a plant be classified? |
Must orbit a star, be large enough for its gravity to make it round, and cleared other objects from its path |
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How old is the universe? |
14 billions years old |
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Observable universe |
Portion of the universe that can be seen from earth |
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Why doesn't galaxies and galaxy clusters not expand with the rest of the universe? |
Their gravity is stronger than the force of expansion. |
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How is a star born? |
When gravity compresses the material in a cloud until the center becomes dense and hot enough to generate energy by nuclear fusion |
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What is nuclear fusion ? |
Lightweight atomic nuclei smash together and stick to make heavier nuclei |
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Supernovae |
Explosion of a star, which can potentially create new stars with the leftover matter |
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Dark matter |
Matter inferred to exist, but no light is detected from it. Dominates total mass of galaxy |
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Ecliptic |
Path the sun follows as it appears to circle around the celestial sphere one a year |
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Why do we always see the same face of the moon? |
It has an equal rotational and orbital period |
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Lunar eclipse |
When the earth is directly between the sun and moon |
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Solar eclipse |
When the moon is directly between the sun and earth |
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Totality |
Portion of a total lunar eclipse during which the moon is fully within earth's umbral shadow |
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Total solar eclipse |
A solar eclipse during which the sun becomes fully blocked by the disk of the moon |
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Why don't we have monthly eclipses? |
Because the moons orbit is slightly inclined to the elecptic plane |
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Apparent retrograde motion |
Apparent motion of a planet during a period of a few weeks or months when it moves westward, if viewed from earth. |
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What is actually happening during apparent retrograde motion of Mars? |
Earth is catching up and passing Mars in their orbits |
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Stellar parallax |
Apparent shift in the position of a nearby star |
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When does a stellar parallax occur? |
When we view a star from different positions in earth's orbit |
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A hypothesis must be____________ |
Falsifiable and testable |
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A theory must be |
Consistent and compatible with evidence, tested in a wide range, and be effective in problem solving |
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Scientific law |
Description of a natural phenomenon or principle that's holds true under certain conditions and occur under certain circumstances |
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What was the problem with copernicus's idea about the planets |
That planetary motion must occur in perfect circles |
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What did Tyco Brahe create? |
More precise evidence for where things were in the sky |
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What was tychos ******* problem? |
Said all planets orbit the sun except for earth. |
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Ellipse |
Type of oval that happens to be the shape of bound orbits |
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Focus |
Points within an ellipse that lie along the major axis |
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Eccentricity |
Measure of how much an ellipse deviates from a perfect circle |
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Semi major axis |
Half the distance across the long axis of an ellipse |
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Keplars laws of planetary motion |
3 laws that describe the motion of the planets around the sun. |
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Keplars 1st law |
All planets orbit the sun like an ellipse with the sun being the foci |
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Keplars 2nd law |
A planet moves faster during orbit when it's close to the sun, and slower when its further |
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Keplars 3rd law |
More distant planets orbit the sun at slower speeds |
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What could Galileo demonstrate with rolling balls ? |
Objects remain in motion unless acted on by another force |
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Occoms razor |
The simplest solution is the right one |
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How can we tell the universe isnt perfect? |
By seeing spots on the sun and craters on the moon |
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Why are there 7 days in a week? |
Because there 7 ******* objects in the visible sky |
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How did the ptolemaic model explain apparent retrograde motion? |
Planets moved along small circles that moved on larger circles around earth |
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What is velocity? |
Combo of speed and direction of motion |
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What changes during acceleration? |
Velocity |
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How is momentum calculated? |
Product of an objects mass and velocity |
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Net force |
Overall force to which an object responds |
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Torque |
A twisting force that can change an objects angular momentum |
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Newton's 2nd law |
States that acceleration of an object is dependent on the net force acting on it and the mass of the object |
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Newtons 3rd law |
For any force there is an equal and opposite force. Explains gravity in some way idk |
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Conservation momentum states that____________ |
In the absence of net force, the total momentum of a system remains constant |
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Conservation of angular momentum states that |
If there's there's no net torque, the total angular momentum of a system remains constant |
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Conservation of energy states that |
Energy can't be created or destroyed |
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What is radiative energy |
Energy carried by light |
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Potential energy |
Energy stored for later conversion into kinetic 3 |
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Thermal energy |
Kinetic energy, as measured by temperature of particles in a substance |
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Gravitational potential energy |
Energy an object has depending on its position in a gravitational field |
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Who discovered potential energy of mass ? |
Einstein |
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1st universal law of gravity |
Every mass attracts every other kind of mass through gravity |
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2nd gravity law |
Strength of gravitational force is proportional to product of masses |
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3rd gravity law |
Strength of gravity between 2 objects decreases between centers |
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Unbound orbits |
When an object comes in towards a large body only once. Para or hyper shapes |
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What is the point where 2 objects would balance if they were connected? |
Center of mass |
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Newtons version of keplars 3rd law is used to calculate_____________________ |
The mass of orbiting objects from measurements of orbital period and distance |
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The sum of planets kinetic and gravitational potential energies is______ |
Orbital energy |
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When 2 objects pass so close they can feel each other's gravity |
Gravitational encounter |
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A force that occurs when gravitational pull is different on either side of an object |
Tidal force |
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A net force acting on an object will cause a change in the _______ |
Momentum |
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4 ways that light can interact with matter |
Emission (bulbs), Absorption (into body), Transmission (glass), reflection/scattering (bounce) |
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Distance between peaks and troughs |
Wavelength |
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Synonym for light |
Electromagnetic field |
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Individual particles of light |
Photons |
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Complete spectrum of light |
Radio, microwaves, infrared, visible, ultraviolet, x-rays, gamma rays |
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What makes up an atom? |
Nucleus, protons, electrons, neutrons |
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What is the atomic number |
Number of protons |
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Atomic mass number |
Number of protons and neutrons |
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When molecules split at high temps and slam ass |
Molecular dissociation |
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Ion |
Atoms positively charged |
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Ionization |
Stripping electrons from atoms |
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Hot gas consisting of ions and electrons |
Plasma |
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Force pushing on objects surface |
Pressure |
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In what ways do atoms contain energy |
Virtue of mass, virtue of motion, and electrical potential energy |
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3 types of spectra |
Continuous, emission line, absorption line(dark) |
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1st law of thermal radiation |
Each square meter of a hotter object surface emits more light |
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2nd law of thermal radiation |
Hotter objects emit photons with higher average energy |
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What is the doppler effect |
Increase or decrease in waves as the source moves toward of away from the observer |
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Rest wavelength |
Wavelength of a spectral feature with no doppler shift |