martin d. weinberg umass astronomy astron100...
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Read: Chap 5, review for Exam 09/25/14 – slide 1
A100–Exploring the Universe: Light and Matter
Martin D. Weinberg
UMass Astronomy
astron100-mdw@courses.umass.edu
September 25, 2014
Announcements
⊲ Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 2
First in-class exam on THURSDAY!
⊲ Multiple choice (40-50 questions)
⊲ Covers Chapters 1,3,4,5
⊲ Use Mastering to help you study!!
Announcements
⊲ Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 2
First in-class exam on THURSDAY!
⊲ Multiple choice (40-50 questions)
⊲ Covers Chapters 1,3,4,5
⊲ Use Mastering to help you study!!
Today: More on Light and Matter (LIGHT, Chap. 5)
⊲ What is the structure of matter?
⊲ What are the phases of matter?
⊲ How is energy stored in atoms?
⊲ What are the three basic types of spectra?
⊲ How does light tell us what things are made of?
Announcements
⊲ Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 2
First in-class exam on THURSDAY!
⊲ Multiple choice (40-50 questions)
⊲ Covers Chapters 1,3,4,5
⊲ Use Mastering to help you study!!
Today: More on Light and Matter (LIGHT, Chap. 5)
⊲ What is the structure of matter?
⊲ What are the phases of matter?
⊲ How is energy stored in atoms?
⊲ What are the three basic types of spectra?
⊲ How does light tell us what things are made of?
Questions?
Properties of Light: Summary
Announcements
⊲ Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 3
Particle properties
⊲ Travels in straight lines (bullets)
⊲ “Rays” are parallel far from source
⊲ E = hν
Wave properties
⊲ “Rainbow” spectrum
⊲ Interference
Light is electromagnetic radiation
Wave-Particle Duality: light has both wave-like and
particle-like properties!
Thought question
Announcements
⊲ Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 4
The higher the photon energy . . .
the longer its wavelength.
the shorter its wavelength.
energy is independent of wavelength.
Thought question
Announcements
⊲ Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 4
The higher the photon energy . . .
the longer its wavelength.
the shorter its wavelength.
energy is independent of wavelength.
Thought question
Announcements
⊲ Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 4
The higher the photon energy . . .
the longer its wavelength.
the shorter its wavelength.
energy is independent of wavelength.
λν = c
Thought question
Announcements
⊲ Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 4
The higher the photon energy . . .
the longer its wavelength.
the shorter its wavelength.
energy is independent of wavelength.
λν = c =⇒ ν =
c
λ
Thought question
Announcements
⊲ Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 4
The higher the photon energy . . .
the longer its wavelength.
the shorter its wavelength.
energy is independent of wavelength.
λν = c =⇒ ν =
c
λ
E = hν
Thought question
Announcements
⊲ Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 4
The higher the photon energy . . .
the longer its wavelength.
the shorter its wavelength.
energy is independent of wavelength.
λν = c =⇒ ν =
c
λ
E = hν =
hc
λ
What is the structure of matter?
Announcements
Summary
⊲
What is thestructure ofmatter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 5
[Atom] [Electron cloud] [Nucleus]
Atomic terminology
Announcements
Summary
What is the structureof matter?
⊲Atomicterminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 6
Atomic Number = # of protons in nucleus
Atomic Mass Number = # of protons + neutrons
Molecules: consist of two or more atoms (H2O,CO2)
Atomic terminology
Announcements
Summary
What is the structureof matter?
⊲Atomicterminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 6
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18hydrogen helium
1 2
H He1.00794(7) Key: 4.002602(2)
lithium beryllium element name boron carbon nitrogen oxygen fluorine neon
3 4 atomic number 5 6 7 8 9 10
Li Be symbol B C N O F Ne6.941(2) 9.012182(3) 2003 atomic weight (mean relative mass) 10.811(7) 12.0107(8) 14.0067(7) 15.9994(3) 18.9984032(5) 20.1797(6)
sodium magnesium aluminium silicon phosphorus sulfur chlorine argon
11 12 13 14 15 16 17 18
Na Mg Al Si P S Cl Ar22.989770(2) 24.3050(6) 26.981538(2) 28.0855(3) 30.973761(2) 32.065(5) 35.453(2) 39.948(1)
potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr39.0983(1) 40.078(4) 44.955910(8) 47.867(1) 50.9415(1) 51.9961(6) 54.938049(9) 55.845(2) 58.933200(9) 58.6934(4) 63.546(3) 65.38(2) 69.723(1) 72.64(1) 74.92160(2) 78.96(3) 79.904(1) 83.798(2)
rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe85.4678(3) 87.62(1) 88.90585(2) 91.224(2) 92.90638(2) 95.96(2) [98] 101.07(2) 102.90550(2) 106.42(1) 107.8682(2) 112.411(8) 114.818(3) 118.710(7) 121.760(1) 127.60(3) 126.90447(3) 131.293(6)
caesium barium lutetium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury thallium lead bismuth polonium astatine radon
55 56 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86
Cs Ba Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn132.90545(2) 137.327(7) 174.9668(1) 178.49(2) 180.9479(1) 183.84(1) 186.207(1) 190.23(3) 192.217(3) 195.078(2) 196.96655(2) 200.59(2) 204.3833(2) 207.2(1) 208.98038(2) [209] [210] [222]
francium radium lawrencium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium ununbium ununtrium ununquadium ununpentium ununhexium ununseptium ununoctium
87 88 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118
Fr Ra Lr Rf Db Sg Bh Hs Mt Ds Rg Uub Uut Uuq Uup Uuh Uus Uuo[223] [226] [262] [267] [268] [271] [272] [270] [276] [281] [280] [285] [284] [289] [288] [293] — [294]
lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium
57 58 59 60 61 62 63 64 65 66 67 68 69 70
Lanthanoids La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb138.9055(2) 140.116(1) 140.90765(2) 144.24(3) [145] 150.36(3) 151.964(1) 157.25(3) 158.92534(2) 162.500(1) 164.93032(2) 167.259(3) 168.93421(2) 173.054(5)
actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium
89 90 91 92 93 94 95 96 97 98 99 100 101 102
Actinoids Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No[227] 232.0381(1) 231.03588(2) 238.02891(3) [237] [244] [243] [247] [247] [251] [252] [257] [258] [259]
WebElements: the periodic table on the world-wide webhttp://www.webelements.com/
Element symbols and names: symbols, names, and spellings are recommended by IUPAC (http://www.iupac.org/). Names are not yet proposed for the elements beyond 111 - those used here are IUPAC’s temporary systematic names (Pure & Appl. Chem., 1979, 51, 381–384). In the USA and some other countries, the spellings
aluminum and cesium are normal while in the UK and elsewhere the usual spelling is sulphur.
Atomic weights (mean relative masses): Apart from the heaviest elements, these are IUPAC 2007 values (Pure & Appl. Chem., 2007, in press). Elements with values given in brackets have no stable nuclides and are represented by integer values for the longest-lived isotope known at the time writing.
The elements thorium, protactinium, and uranium have characteristic terrestrial abundances and these are the values quoted. The last significant figure of each value is considered reliable to ±1 except where a larger uncertainty is given in parentheses.
Periodic table organisation: for a justification of the positions of the elements La, Ac, Lu, and Lr in the WebElements periodic table see W.B. Jensen, “The positions of lanthanum (actinium) and lutetium (lawrencium) in the periodic table”, J. Chem. Ed., 1982, 59, 634–636.
Group labels: the numeric system (1–18) used here is the current IUPAC convention. For a discussion of this and other common systems see: W.C. Fernelius and W.H. Powell, “Confusion in the periodic table of the elements”, J. Chem. Ed., 1982, 59, 504–508.
©2007 Dr Mark J Winter [WebElements Ltd and University of Sheffield]. All rights reserved. For updates to this table see http://www.webelements.com/nexus/Printable_Periodic_Table. Version date: 21 September 2007.
Atomic terminology
Announcements
Summary
What is the structureof matter?
⊲Atomicterminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 6
Atomic terminology
Announcements
Summary
What is the structureof matter?
⊲Atomicterminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 7
Isotope: same # of protons but different # of neutrons.
(4He, 3He)
4 Fundamental Forces (aside)
Announcements
Summary
What is the structureof matter?
Atomic terminology
⊲ 4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 8
Physicists have identified four natural forces
1. Gravity
Holds the Sun and planets together in the solar
system
Holds stars together in galaxies
Things fall “down” on Earth
4 Fundamental Forces (aside)
Announcements
Summary
What is the structureof matter?
Atomic terminology
⊲ 4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 8
Physicists have identified four natural forces
1. Gravity
Holds the Sun and planets together in the solar
system
Holds stars together in galaxies
Things fall “down” on Earth
2. Electromagnetism: a force between objects with electric
charge
Holds atoms together
Responsible for chemical reactions
Friction of book on table
Magnets
Fundamental Forces
Announcements
Summary
What is the structureof matter?
Atomic terminology
⊲ 4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 9
3. Strong force
Holds nuclei of atoms together
Generation of energy in stars, supernovae
Power, bombs
Fundamental Forces
Announcements
Summary
What is the structureof matter?
Atomic terminology
⊲ 4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 9
3. Strong force
Holds nuclei of atoms together
Generation of energy in stars, supernovae
Power, bombs
4. Weak force
Radioactive decay
Also energy in stars, supernovae
Fundamental Forces
Read: Chap 5, review for Exam 09/25/14 – slide 10
Interaction Current Theory Strength Range (m)
Strong Quantum chromodynamics (QCD) 1038 10−15
Electromagnetic Quantum electrodynamics (QED) 1036 (Infinite)Weak Electroweak Theory 1025 10−18
Gravitation General Relativity (GR) 1 (Infinite)
Phases & Pressure
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
⊲ Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 11
Phase of a substance depends on both temperature and
pressure
Often more than one phase is present
Phases & Pressure
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
⊲ Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 12
Example: familiar phases (of water)
Solid (ice)
Liquid (water)
Gas (water vapor)
Phases of same material behave differently because of
differences in chemical bonds
Phases & Pressure
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
⊲ Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 12
Example: familiar phases (of water)
Solid (ice)
Liquid (water)
Gas (water vapor)
Phases of same material behave differently because of
differences in chemical bonds
Less familiar phase:
Ionized (plasma), no chemical bonds
Phases & Pressure
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
⊲ Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 13
Ionization: Stripping of electrons,
changing atoms into plasma
Dissociation: Breaking of molecules
into atoms
Evaporation: Breaking of flexible
chemical bonds, changing liquid into
solid
Melting: Breaking of rigid chemical
bonds, changing solid into liquid
Thermal or Blackbody Radiation
Read: Chap 5, review for Exam 09/25/14 – slide 14
Electromagnetic radiation is caused by moving charges
⊲ Electrons in a radio antenna
⊲ Accelerated electrons in an X-ray tube
Most material objects are made charged particles
Thermal or Blackbody Radiation
Read: Chap 5, review for Exam 09/25/14 – slide 14
Electromagnetic radiation is caused by moving charges
⊲ Electrons in a radio antenna
⊲ Accelerated electrons in an X-ray tube
Most material objects are made charged particles
The temperature of an object proportional to vibration of charges
0
0.1
0.2
0.3
0.4
0.5
0.6
0 1 2 3 4 5 6 7 8
Fra
ctio
n w
ith g
iven
spe
ed
Speed
cold
warm
hot
Maxwell Distribution
[demo]
Thermal or Blackbody Radiation
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
⊲ Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 15
Examples:
⊲ Hot objects glow! (Fireplace, stove top, . . . )
⊲ Cooler objects like the human body are emitting
radiation as well, though mostly at longer
wavelengths, in the infrared.
Thermal or Blackbody Radiation
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
⊲ Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 15
Examples:
⊲ Hot objects glow! (Fireplace, stove top, . . . )
⊲ Cooler objects like the human body are emitting
radiation as well, though mostly at longer
wavelengths, in the infrared.
Thermal or Blackbody Radiation
Read: Chap 5, review for Exam 09/25/14 – slide 16
Planck (1900) was trying to understand the nature of radiation that filled
an enclosure that had come to equilibrium
This emission of radiation that de-
pends on an objects temperature is
called thermal or blackbody radia-
tion
A perfect blackbody reflects no light
(it’s only truly black at 0◦ K)
When heated, a blackbody glows
with a continuous spectrum which
depends only on its temperature
Thermal or Blackbody Radiation
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
⊲ Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 17
Planck measured the amount of energy in the radiation
as a function of wavelength
Their results could be displayed as a kind of histogram,
with energy plotted against small wavelength intervals
(a distribution)
Shapes of the curves depended only on the temperature
of the enclosure, and not on the material inside
This energy distribution became known as the
Universal Planck Radiation Law
Thermal or Blackbody Radiation
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
⊲ Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 18
Distribution for different T
Thermal or Blackbody Radiation
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
⊲ Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 18
Distribution for the Sun
Thermal or Blackbody Radiation
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
⊲ Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 19
Wien’s Law
λpeak =0.29
T (◦ K)cm
=2.9× 10−3
T (◦ K)m
=2.9× 106
T (◦ K)nm
Allows us to estimate the temperature of celestial bodies!
Spectra of elements
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
⊲Spectra ofelements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 20
Kirchoff & Bunsen (c1850): Each chemical element
produces a unique set of spectral lines
Not a Planck spectrum!
Types of Spectra
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
⊲ Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 21
Kirchoff & Bunsen cataloged spectra of all known
elements
Observed spectrum of Sun
⊲ Part of solar spectrum (upper)
⊲ Iron lines in lab (lower)
Pattern matches elements whether dark or light lines
Lines found in Sun not known on Earth:
discovery of Helium!
How is energy stored in atoms?
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
⊲ Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 22
Electrons in atoms are restricted to particular energy
levels
Internal energy
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
⊲ Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 23
Energy Level Transitions
The only allowedchanges in en-ergy are thosecorrespondingto a transitionbetween energylevels
Internal energy
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
⊲ Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 23
Energy Level Transitions
Disallowed!
The only allowedchanges in en-ergy are thosecorrespondingto a transitionbetween energylevels
Internal energy
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
⊲ Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 23
Energy Level Transitions
Disallowed! Allowed!
The only allowedchanges in en-ergy are thosecorrespondingto a transitionbetween energylevels
Chemical fingerprints
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
⊲ Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 24
Downward transitions
produce a unique pattern
of emission lines
Because those atoms can
absorb photons with those
same energies, upward
transitions produce a pat-
tern of absorption lines at
the same wavelengths
[demo]
Chemical fingerprints
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
⊲ Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 25
Each atom has unique spectral figureprint
Kirchhoff’s Laws
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
⊲ Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 26
1. A dense (opaque) hot object emits a continuous
spectrum
2. A cool tenuous cloud emits discrete spectral lines
3. A hot opaque object viewed through a cool cloud shows
a continuous spectrum with absorption lines
Virtually every astronomical observation fits in one of these
categories.
Types of Spectra
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
⊲ Types of Spectra
Continuous spectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 27
Continuous spectrum
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
⊲Continuousspectrum
Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 28
The spectrum of a common (incandescent) light bulb
spans all visible wavelengths, without interruption
Example: Solar spectrum
Announcements
Summary
What is the structureof matter?
Atomic terminology
4 forces
Phases & Pressure
Thermal radiation
Spectra of elements
Types of Spectra
Internal energy
Kirchhoff’s Laws
Types of Spectra
Continuous spectrum
⊲ Solar spectrum
Read: Chap 5, review for Exam 09/25/14 – slide 29
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