Final Study Guide PDF

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Planet Earth Semester 2 Final Study Guide Beginning ● Don’t know how exactly the universe began ● The light we see helps us figure out age, size etc. of the stars ● Standard Model of the Universe ○ Predicts evolution of the universe ● Solar System ○ Star with planets going around it ● Galaxy ○ Group of stars (or solar systems) ex. Milky Way ● 1 Light year= 6 trillion miles ● Higher the temperature more simple the laws of nature get ● High Energy physics= building blocks of nature ● Universe is considered infinite according to most scientists ● Age of current universe: 13.6 billion years ● 4 Forces of Nature ○ Gravity: F=GM1M2/r^2 ■ Distance: 1/r^2 ■ Source: Gravitational Charge (mass (m)) ■ Receiver: gravitational charge (mass (m)) ■ Attractive only ■ Large scale structure ■ Stability of the universe ○ Electric Magnetic (E&M): F=kq1q2/r^2 ■ Distance= 1/r^2 ■ Source: Electric charge (q) ■ Receiver: Electric charge (q) ■ Attractive AND repulsive ■ Stability of atoms/molecules/matter ○ Strong Nuclear: Don’t know an equation ■ Distance: 10^-13cm (scotch tape) ■ Source: strong charge… color ■ Receiver: Strong charge… color ■ Attractive AND repulsive ■ Stability of atomic nucleus ○ Weak Nuclear: Don’t know an equation ■ Distance: 10^-16cm ■ Source: weak charge- isospin ■ Receiver: weak charge- isospin ■ Radioactive decay ■ Instability of matter ● OVERVIEW of Forces

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Range ■ Gravity: infinite ■ E&M: infinite ■ Strong: Short ■ Weak: VERY Short ○ Strength ■ Strong: 1 ■ E&M: 10^-2 ■ Weak: 10^-13 ■ Gravity: 10^-42 (VERY weak) ○ Mediators ■ Strong: gluons ■ E&M: photons ■ Weak: weakons ■ Gravity: gravitons How to detect a force: when a force acts, something moves, force generates acceleration F=ma M (mass) determines how much acceleration results from a given force All 4 forces generate accelerations given by Newton’s 2nd law (F=ma) Acceleration: Change in Speed: A=change in V/change in T The Particle Zoo ○ Protons and neutrons have parts (quarks) ○ Probing them at higher and higher energies yields more particles because of spontaneous creation using E=mc^2 Quark, gluon, electron are fundamental particles As you move away from the sun gravity becomes weaker

Ways of Knowing (random facts from the ppt) ● Sun is at the center of a system of planets called the solar system(10 billion year lifetime-now at middle-age). ● Earth is about 100 million miles from the sun. ● Pluto is about 4 billion miles out. ● Nearest star is about 24 trillion miles distant (or 4 light years). ● The atom is about one ten billionth of a meter; the nucleus of an atom is about ten thousand times smaller than this. ● The current limit of observation is about one thousand times smaller that this. This requires a temp of a thousand trillion degrees Kelvin, which occurred a ten billionth of a second after big bang ● Atoms are made up of protons neutrons and electrons. The electron appears to be fundamental - the proton and neutron appear to have parts. ● Our sun is an average star among 100 billion stars grouped in the Milky Way Galaxy ● The Milky Way Galaxy is about 600,000 trillion miles in diameter(100,000 light years)

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There are about a billion Galaxies Galaxies are in clusters about 60 million light years in diameter ○ separated from each other by more than 60 million light years ○ Galaxies in the clusters are separated from each other by about 150,000 light years

Atomic Structure ● Greeks BC: ○ Democritus- indivisibility, a tomos (not divisible) ○ Lucretius- motion ● Dalton: ○ N2+02= 2NO (individual atoms that join and pair together) ● Avogadro: ○ Equal gas volumes= equal number of atoms ● Brown ○ Atoms have random motion ● Faraday ○ 2h20= 2H+ 02 (split apart atoms) ● Mendeleev ○ Periodic Table of Elements ○ Column- similar chemical reactions and same configuration in electrons ○ Table of Nuclides- table about flavors that each element comes in ● Becquerel and Curies ○ Radioactivity ○ α= Helium nucleus ○ β= electron = 1/7000 mass of the α ○ γ = quantum of energy (light) ● Thomson ○ Cathode rays= electrons ○ Chocolate chip cookie model of matter ● Rutherford ○ Scattering experiment Plum Pudding Model Most of matter is empty space, massive and positive charge nucleus ● Mediator of electric force= gamma Bohr Model of the Atom ● Model of the atom with a positively charge nuclear and negative charge in cloud surrounding it ○ Nucleus- Protons and Neutrons ■ Protons- +1 charge, heavy weight, very tiny ■ Neutrons- 0 charge, very tiny, heavyweight ■ Held together by strong nuclear force ■ Transformations possibly by weak nuclear force

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Neutrons into protons

Electron Cloud ○ Electrons ■ Charge of -1 ■ Very small ■ Lightweight ■ Atom held together by electric and magnetic force (electron cloud to nucleus) Definitions ○ Atomic number: gives the identity of the element ■ # of protons in the nucleus ■ # of electrons in a neutral atom ○ Atomic mass: combined mass of protons and neutrons ○ Isotopes: elements with same atomic number but different atomic masses ■ Not all isotopes are stable→ resulting in radioactivity Quantized energy levels exist in all atoms ○ Energy level in hydrogen is 13.6 ○ Transition between levels ■ Absorb or release ● Release in the form of light light or photons ■ Energy level is the difference between two states

Temperature and Heat ● Farheneit ○ Water boils: 212 ○ Water freezes: 32 ○ Absolute zero: -458 ● Celsius ○ Water boils: 100 ○ Water freezes: 0 ○ Absolute zero: -273 ● Kelvin ○ Water boils: 373 ○ Water freezes: 273 ○ Absolute zero: infinite ● Extended Systems ○ Rigid: even though extended, all particles move as a unit ○ Non-rigid Streamline: even though particles are not connected they seem to move as a unity ○ Non rigid random: cannot be described by looking at a single particle.. Motions → impossible ○ Extended Non rigid systems gases and liquids: listing individual speeds, forces, positions is impossible for even small parts of real systems

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Pressure= Force/ Area Average kinetic energy= ½ mv^2 Ideal Gas Law: PV=NKT ○ N= number of molecules ○ K=constant ○ Empirical relationship between pressure, volume, temperature with no reference to particle kinematics Heat ○ Cold air is more dense than warm air ○ Temperature= average speed of particles ○ The amount of calories entering or leaving a body ■ 1 calorie=heat necessary to raise the temp of 1 gm of water 1*C ○ Total energy put into a system ○ Q=(3/2)NkT ■ Q=heat ■ N=total # of particles ○ Temperature and molecular motion are related ■ = (3/2)kt States of Matter ○ Solid: requires 330 joules/gm of ice to get liquid water ○ Liquid: requires 2260 joules/gm added to liquid to get steam gas ○ Gas Specific Heat Capacity (C) ○ If different substances take up the same amount of “heat” they all should reach the same temp ■ But they DON'T ○ C= (1/m) * change in Q/ change in T ○ Specific heat capacity can be predicted if one knows the number of ways a system can move (or can absorb energy) Measuring Temperature ○ Act of measuring temperature changes the temperature ○ T= 2/ kf ■ F: number of ways a system can move ● Higher the f, smaller the change, more complicated the systems Heat Transfer ○ Conduction: energy imparted by direct contact-- collision ○ Convection: energetic particles move from one place to another ○ Radiation: Light -- this is like convection but no medium is needed

Waves ● There seem to be two basic descriptions of nature, particle and wave. ○ Particle - well localized object moving from one place to another. Particles scatter off of one another.

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position, speed and acceleration are used to describe the kinematics of particle. ■ "Pete Rose" equation ● V=Vi + at ○ Wave - non localized, no object actually moving from one place to another but information is transported from one place to another. Waves exhibit "superposition”, i.e. "no scattering" ■ Wave speed, v, the speed with which the information is carried from one place to another. No acceleration is associated with this speed. ■ A disturbance is created in the medium say a string by jiggling one end, then the disturbance travels down the string at constant speed. ● If this disturbance is repetitive then the deformation of the string is a regular recognizable shape. ■ Waves don’t divert when they go through each other ■ Superposition: add to each other where the 2 hit each other ○ 2 Types of Waves ■ Longitudinal: the disturbance causing the wave is in the same direction as the propagation of the info ● Travel farther ● Ex. slinky ● Sound waves ● P waves: earthquakes (shock) ■ Transverse: The disturbance causing the wave is perpendicular to the direction of propagation of information ● Higher the frequency, the shorter the wavelength, shorter period ● Can travel thru rocks ● Waves on a string ● Water waves ● Light waves ● S waves: earthquake ○ Properties of Waves ■ Reflection: bouncing back from a boundary ■ Refraction: light going from 1 medium to another will bend (ex. Hitting water)? ■ Interference: 2 waves can occupy the same place at the same time… they “interfere” and go on (don’t scatter) ● Can be constructive or destructive ■ Diffraction: bending of light around or thru an obstacle (look close and this is interference as well) ○ Wavelength: λ = v T Waves reflect, particles scatter

● Light ● Light can behave like a particle (duality)

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13.6 ev= work/ energy necessary to rip an electron from atom Color ○ Ratio of intensities through 2 different color filters ○ Each color has a different wavelength ○ Blue light= hottest ■ Objects get more blue with increasing temperature ○ Color of an object tells its temperature Intensity of light increases → light energy increases Distance behavior ○ I= A/r^2 +B Attenuation ○ I = I0• e-l•d Observations - visible for Hydrogen ○ 1/l = R(1/22 - 1/n2) , R = 1.097 •107 m-1 ○ n = 3 red light l = 6562 •10-10 ○ n = 4 blue light l = 4861 •10-10 ■ This is an empirical formula! ■ Each atom has a unique spectrum! ■ Formulas like this, give the colors of light that come out of atoms. Speed of light c= 3 x 10^8 ○ Constant speed Energy= hf ○ Higher the energy → higher frequency Human body released in infrared Light needs NO medium to travel through

Continuous Thermal Radiation ● All wavelengths are present, resulting from thermal motion from solids and liquids ● Long wavelength → low energy (red) ● Sun light = radiation ● Red object = cool = 4000k ● Curve of continuous thermal radiation (image below) ○ Coolest: 310 k ○ Most intense, hottest object: 15,000 K star

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The Sun ● The “engine” of the solar system ● Behaves like a liquid ● Sun light= radiation ● Most important star ● 400x bigger than the moon ● Moon= 400x closer than the sun ● Only star that we can observe its surface ● Rotation is about a month ● Mass= 2x10^30 kg ○ A very average size star (lots are bigger and smaller) **in terms of mass** ● Density= mass/volume= 1.4 g/cc ○ Very similar to water ● Luminosity: measured using spacecraft above earth’s atmosphere ○ L= 4x10^26 watts, 2x10^17 watts @ earth ● Rotates faster @ equator than at poles because it is a gaseous ball ● Smaller wavelength= brighter, larger wavelength= dull ● Surface temp= 6000 Kelvin ○ Used as a standard for measuring other stars ● Absolute magnitude of star = 5 ● Apparent brightness of a star just visible to naked eye is 6 ● Spectral Lines: can see what elements are in the universe ● Magnetic loops on sun= linking sunspots ● Sunspot cycle: Come and go in about 11 years ○ Discovered by German Schwabe ○ # of sunspots fluctuates a lot ○ Sun heats up when there’s lots of spots ○ Little ice age in Europe= same time sunspots disappeared (1640-1710/20) ○ When the magnetic field is just right, there’s more sunspots ○ Sunspots are cooler surfaces on the sun ● Corona: discovered during a total solar eclipse ○ Outermost part of the sun ○ Hottest part of the sun ● Photosphere ○ Innermost part of the sun ○ Coldest part ● Color of Sun tells you temperature ○ Appearing white/blue=hot

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○ Appearing red=cold Aurora ○ Interacting with earth’s atmosphere ○ Connected to the sun ○ Auroral displays can be expected whenever the sun exhibits flares or coronal mass ejections Sun is a G type star ○ Take very long to form

Stars ● Blue / white star = hot ○ Hotter → bluer ● Red star= cool ● Stars tell temperature ● Constellations ○ Groupings of stars ● Bright stars ○ Proper names ○ Make up the constellations ○ Negative numbers ■ Bigger the number the dimmer the star ● Trigonometric parallax ○ Parallactic angle ■ Closer stars have larger parallaxes ○ Indirect methods to discover distance of stars ● Brightness ○ Apparent brightness → apparent magnitude ○ Apparent brightness → absolute magnitude ○ Absolute magnitude → Apparent magnitude → distance ● Color of an object is described in an objective way ● Electrons can only have certain energies ○ Only have certain levels ○ Can move from one state to another ● Spectral emission lines ○ Pattern → what star is made up, temperature ■ A star: strong lines ■ M star: barely any lines ■ O star: are hottest ■ M star: coolest ● Stars are mostly hydrogen and helium ● Main sequence of stars ○ Stars in prime of their lives

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○ Fairly stable, live out most of their lives Stars with iron in their core ○ Towards the end of their lifetime Fusion of stars ○ Stars fuse lighter elements into heavier elements Illuminate the universe Period elements come from stars Brighter a star → hotter a star Stellar evolution ○ 4 matters of matter/ objects ■ Conventional matter: familiar with ■ Degenerate matter: electrons don't know what nucleus they belong to ■ Neutron matter ■ Singularity ○ Stars go from conventional matter → white dwarf → degenerate Mass ○ Vary by .1 ■ Anything less than .1 is a planet ○ Most massive: 100 ○ Less massive stars take longer to form (M star) ■ Less gravity, burn fuel slowly ■ Live longer ○ More massive stars do everything faster ■ A star ● 1 million years to form ■ More gravity, burn fuel faster ● Burn themselves up ○ O and B stars ■ Form period table Escape speed > speed of light → event horizon Interstellar medium ○ Where stars come from Stellar nursery ○ Informal grouping of stars ○ Formation of stars Stellar birth ○ Star affects nearby disk by “eating up” dust ■ Causes them to shine brightly ○ Light has hard time going through dust/ gas ■ Empty spaces ○ Messier objects= star cluster Ca’ts eye nebula will become a white dwarf ○ When outer layers becomes transparent it will become a white dwarf

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Ex. white dwarf: Eri B With more mass white dwarfs get smaller ■ Cannot sustain itself after 1.4 Sun and stars can take hydrogen and turn it into helium, carbon nitrogen More massive the nucleus, the more particles you have ○ Lighter → heavier → produce energy (Exothermic) ○ Heavier → lighter → give off energy When a star runs out of hydrogen and helium ○ Cannot protect itself Detection of neutrino ○ Bundle of energy, produce neutrons, and protons Supernovas ○ Stellar evolution cannot go beyond iron/nickel ○ Supernova can produce heavier elements ○ Can destruct entirely or leave behind a neutron star Pulsars ○ Cannot see ○ When a pular comes near you → energy ○ Neutron star

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Stars arrange themselves on the main sequence by mass ○ Sun will leave main sequence eventually You are a child...