Index to Essays on Physics

absolute conservation laws, G10
action and reaction, M3
action at a distance, E6, M4
Aepinus, Franz, E1
agreement among observers, R1
airspeed, hypothetical meter, R3
alternating current, E5
Ampère, André-Marie, E2, E3, E8
Anderson, Philip, G16
angular momentum, M8
conservation of, M10
quantization of, Q2
vector nature of, M8
annihilation and creation, Q1, Q4
Arago, Dominique, E6
Aristotelian physics, G1
Aristotelian science, G16
Aristotle, G12, G13, M2
arrow of time, T9
atom building, Q15
atomic number, Q15
available energy, T6

Bacon, Francis, G2
Balmer series, Q13
Bartholinus, Erasmus, E6
Becquerel, Henri, G15, N5
Bernoulli, Daniel, T7
beta decay, Q4
of neutron, Q4
Biot, Jean Baptiste, E2
Bohr atom, Q11, Q12, Q13
key postulates of, Q12
Bohr, Niels
and probability in quantum mechanics, Q3
and the Rydberg constant, Q13
and significance of Planck’s constant, Q2
and theory of fission, N6
and theory of the hydrogen atom, Q11, Q12
Bohr radius, Q14
Boltzmann, Ludwig, T3, T7
Boltzmann’s constant, T3, T5
Born, Max, Q3
bosons as exchange particles, G8
Brahe, Tycho de, G3
branching ratio, Q3

caloric, T2, T7
Carnot, Sadi, T5, T7
cavity (hohlraum) radiation, Q9
center of mass, M3
chaos, submicroscopic, G17
charge, E1
compared with mass, E1
conservation of, G9
chart of nuclei, N2
classical laws as laws of permission, G9
Clausius, Rudolph, T7, T9
Clifford, William, R11
closed shell, Q15
cobalt 60, Q3
color charge, G8
concept in physics, G4
conservation laws, G9, G10
absolute, G10
as laws of constraint, G17
as laws of prohibition, G9
partial, G10
Copernican universe, R2
correspondence principle, Q12, Q13, Q14
cosmology, R11
Coulomb, Charles, E1
Coulomb energy (in nucleus), N6
Cowan, Clyde, N4
creation and annihilation, Q1, Q4
creation vs. discovery, G2
Curie, Marie, N5
Curie, Pierre, N5

DD reaction, N8
de Broglie equation, N1, Q5, Q7, Q10
de Broglie, Louis, Q5
Debierne, André, N5
degrees of freedom, T3
frozen, T4
Descartes, René, G2
deuteron, stability of, N3
Dicke, Robert, M7
diffraction, E6
dimensionless physics, G6
dimensions, G6
Dirac, Paul, E3, G11
disagreement among observers, R1
about time, R4
discovery vs. creation, G2
disorder, T5
Dorn, Ernst, N5
DT reaction, N8

E = mc², R6, R7
derivation of, R6
and momentum conservation, R7
Einstein, Albert
and the corpuscle of light (photon), Q2, Q3, Q9
and E = mc², R6
and general relativity, G15, G18, R11
and gravitational radiation, E1
and invariance, R1
and the Lorentz transformation, R2
and Mach’s principle, R9
and the postulates of special relativity, R5
and the principle of equivalence, R10
and special relativity, E8
electric charge. see charge
electric field, E4
electrical force vs. gravitational force, E1
electricity linked to magnetism, E2
electromagnetic force, G8
electromagnetism
history of, E8
summarized laws of, E4
electron
discovery of, G15
spin, E3
electron-electron scattering, Q16
electron-positron annihilation, Q16
electrons in the nucleus (not), N1
emergence, G16
energy, M11
available and unavailable, T6
distribution of, T7
importance of, M11
internal, T7
kinetic, M12
multiple kinds of, M11
potential, M12
properties of, M11
energy conservation
submicroscopic, Q12
energy levels in atoms, Q15
entropy, T5, T7
Clausius definition of, T8
subtleties of, T8
Eötvös, Loránd, M7
equations, role in theory, G4
equipartition, T3
equipartition theorem, G15, T3
equivalence, principle of, R10
error, M14
error bars, M14
event as spacetime point, R8
events, Q16
exchange particles, G8
exclusion principle, Q15
and nuclear stability, N2
experiment and theory, G3
experiment vs. observation, G1
explanation in science, G13
exponential decay, Q3

faith in simplicity, G1
Faraday, Michael, E1, E5
Fermi, Enrico, Q4
ferromagnetism, E3
Feynman diagrams, Q16
Feynman, Richard, Q16
fission, theory of, N6
flavor, G10
force concept, M4
forces, four kinds of, G8
four-vector, R8
fourth dimension, R8
frames of reference, inertial, M2, R9
Franklin, Benjamin, E1
Fraunhofer, Joseph von, E6
Fresnel, Augustin, E6
friction, M12
Frisch, Otto, N6
fusion power, N8
fusion reactions. see thermonuclear reactions

Galilean invariance, R1
Galilean relativity, R2
Galilean transformation, R2, R5
Galileo Galilei
and arguments for Copernican universe, R1
and early mechanics, G3
and inertial motion, M13
and observation of the Moon, G12
and properties of weight, M7
Geiger counter, Q3
Geiger, Hans, Q3
geometrodynamics, R11
Gilbert, William, M13
gluons, G8
Goudsmit, Samuel, Q2
GPS, R11
granularity in quantum mechanics, Q1, Q2
gravitation, universal, M13
gravitational force, G8, M7
compared with electrical force, E1
gravitational mass, M7
gravitational radiation, E1
graviton, G8
Gray, Stephen, E1
“great theories,” G5

Hahn, Otto, N5
half life, Q3
Halley, Edmund, M13
heat
flow of, T5
and work, T2, T8
heat engine, T5
heavens, study of, G12
Heaviside, Oliver, E8
Heisenberg, Werner, G10, Q3, Q6. see also uncertainty principle
Henry, Joseph, E5
history, physics at end of 19th century, G15
hohlraum. see cavity (hohlraum) radiation
homogeneity of space, M5
Hooke, Robert, G3, M13
Huygens, Christian, E6, G14, M13
Huygens’ principle, G14
hydrogen atom
quantum numbers in, Q14
quantum theory of, Q13
size of, Q7
wave functions in, Q14
hydrogen bomb, N8

inductance, E5
induction of fields, E8
inductor, E5
inertia, M6
of energy, R10
inertial frames of reference, M2, R9
inertial mass, M6
Infeld, Leopold, G18
infrared, E6
interference, E6
internal energy, T2, T7
interval, R5, R8
invariance, R1, R2
for electromagnetic laws, R2
for Newtonian laws, R2
relation to conservation, M5
relation to symmetry, M5
and relativity, R5
Io (moon of Jupiter), E6
isospin, G10
isotopes, N5

Jeans, Sir James, G15
Joule, James, T7

Kelvin, Lord, T7
Kepler, Johannes, G3, M13
Kepler’s laws, M13
contrasted with Newton’s laws, M13
kilogram (unit), G6
kinetic energy, M12
Kramers, Hendrik, Q3
Krönig, August, T7

Laplace, Pierre, T7
laws of permission and prohibition, G9
Lenz, Emil, E5
Lenz’s law, E5
Leverrier, Urbain, G15
light
constancy of speed of, R4
particle theory of, E6
puzzles about, E6
scattering by light, G14
speed of, E6
wave theory of, E6
why speed c?, E7
line of stability, bending and ending, N2
liquid-droplet model, N6
lithium deuteride, N8
Lorentz, Hendrik, G15, R2
Lorentz transformation, R2
Lyman series, Q13

Mach, Ernst, R9
Mach’s principle, R9
magnetic field, E4
magnetic force, E2
magnetic poles, E3
magnetism linked to electricity, E2
Malus, Etienne, E6
mass
equivalence of inertial and gravitational, M7
gravitational, M7, R10
inertial, M6, R10
not velocity-dependent, R7
as a scalar quantity, M6
mathematics
and science, G11
as tool and toy, G11
Maxwell, James Clerk
and electromagnetic radiation, E1
and the history of electromagnetism, E8
and late 19th-century physics, T7
and the speed of light, E7
McCoy, Herbert, N5
mean life, Q3
Meitner, Lise, N6
Mercury perihelion, precession of, G15
meter (unit), G6
method in science, G2, G3
Michelson, Albert, G15, R3
Michelson-Morley experiment, G15, R3
Minkowski, Hermann, R8
momenergy, R8
momentum
conservation of, M2, M4
and Newton’s third law, M5
relativistic, R7
monopole, E3
“more is different,” G16
Morley, Edward, G15, R3
motion
backward in time, Q16
celestial and terrestrial, G12

natural motion, M2
Neptune, discovery of, G3
neutrinos, N4
from the Sun, G10
neutron-proton force, N3
neutron, stabilization of, N3
Newton, Isaac
and the development of mechanics, G3
and equivalence of inertial and gravitational mass, M7
and his first law, E6, M2
and his second law, M7
and the interpretation of Kepler’s laws, M13
Newton’s first law, M2, R9
defining inertial frames, R9
Newton’s laws, M2, M3
contrasted with Kepler’s laws, M13
first, M2, R9
third, M3, M4, M5
Nicholson, John, Q2
nuclear fission, N6
nuclear stability, N3
line of, N2
nuclei, chart of, N2
nucleus, absence of electrons in, N1

objectivity, R1
Oersted, Hans Christian, E2, E8
order and disorder, T5

partial conservation laws, G10
particle theory of light, E6
particles
decay of, Q3
virtual, G17
particles and waves, Q1, Q5
Paschen series, Q13
Pauli, Wolfgang, N4
famous letter of, N4
periodic table, Q15
permeability of space, E7
permission, laws of, G9, M5
permittivity of space, E7
perpendicularity in electromagnetism, E4
perpetual motion, atomic, T4
perpetual motion machines, T5
phase change, T4
photoelectric effect, Q9
photons
Bohr’s non-acceptance of, Q12
as exchange particles, G8
physical vacuum, G17
pion decay, Q16
pions, G10
Planck length, G6
Planck, Max
and gravitational effect on energy, R10
and introduction of Planck’s constant, G15
and Planck length, G6
and Planck’s constant, Q2
and quantized energy transfer, Q9, T4
Planck time, G6
Planck’s constant, Q2, Q9, Q10, T4
as quantum mechanics’ central concept, G6
planetary systems, G13
plasma, T4
Poincaré, Henri, G15
positron
annihilation of, Q16
as backward-in-time electron, Q16
power, M12
Principia, M2, M3, M4
evolution of mechanics following, M10
probability
and disorder, T5
and experimental error, M14
fundamental, Q3
of ignorance, Q3
in molecular collisions, T3
in quantum mechanics, Q1, Q3
and the second law of thermodynamics, T5, T9
three kinds of, G7
prohibition, laws of, G9, M5
proton-neutron force, N3
proton-proton cycle, N7
protons in the nucleus, N2

Q–ℰ–ℬ triangle, E4
quantum jumps, Q12
quantum mechanics, key ideas of, Q1
quantum number
orbital, Q14
orientation, Q14
principal, Q14
spin, Q14

radioactive series, N5
radioactivity, N5
reductionism, G10, G16
refraction, double, E6
Reines, Frederick, N4
relativity
and invariance, R5
of observation, R1
principle of, R5
theory of special, R5
right-hand rule, M8
Ritz combination principle, Q12
Ritz, Walther, Q12
Romer, Alfred, N5
Rømer, Ole, E6
Ross, William, N5
Rutherford, Ernest
and the Bohr atom, Q12
and the discovery of the nucleus, N5
and late 19th-century physics, G15
and Niels Bohr, Q11
and probability, Q3
and transmutation, N5
Rydberg constant, Q13
Rydberg, Johannes, Q13

Savart, Felix, E2
scalars and scalar quantities, M1
Schrödinger, Erwin, Q5
science
future path of, G18
and mathematics, G11
nature of, G2
old and new, G13
pace of progress of, G18
scientific method, G2, G3
second (unit), G6
second law of thermodynamics, T5, T9
six versions of, T5
self-interaction, G17
shells, atomic, Q15
simplicity, faith in, G1
simultaneity, relativity of, R4
Slater, John, Q3
Soddy, Frederick, N5, Q3
solenoid, E3
Sommerfeld, Arnold, Q2
space
homogeneity of, M5
isotropy of, M10
uniformity of, M4
spacetime, R8
spacetime map, Q16
special relativity, R5
postulates of, R5
specific heat capacity, T3
speed of light
constancy of, R4
as relativity’s central concept, G6
spin of electron, E3
stability of nuclei, N3
stationary states, Q12
strong force, G8
strontium 90, Q3
subjectivity, R1
submicroscopic world in introductory physics, G16
Sun, thermonuclear reactions in, N7
superposition, G14
limited validity of, G14
surface-tension energy, N6
symmetry
relation to conservation, M5
of space, M5
system of the world, G12, G13

temperature, T3
theories, “great,” G5
theory
and experiment, G3
nature of, G4
thermodynamics
evolution of, T7
nature of, T1
second law of, T9
thermonuclear reactions
on Earth, N8
in the Sun, N7
thermonuclear weapons, N8
Thomson, J. J.
and confirmation of isotopes, N5
and discovery of the electron, E1, G15
and Niels Bohr, Q11
and relativistic momentum, R7
Thomson, William, T7
thorium, N5
time
arrow of, T9
nature of, T9
relativity of, R4
time-reversal invariance, T9
time’s arrow, T9
torque, M9
relation to angular momentum, M9
vanishing of internal, M9
transmutation, N5
early history of, N5
transverse vibrations, E6
tunneling, Q3
twin paradox, R9

Uhlenbeck, George, Q2
ultraviolet, E6
unavailable energy, T6
uncertainty, M14
kinds of, G7
statistical, M14
uncertainty principle, Q6
as key idea of quantum mechanics, Q1
and submicroscopic chaos, G17
and virtual particles, Q16
units, natural, G6
uranium, N5
radioactivity of, N5
series, N5

van der Rohe, Ludwig Mies, G16
vectors and vector quantities, M1
vertices, Q16
virtual particles, G17

W particle, G8
wave functions in hydrogen atom, Q14
wave-particle duality, Q5
wave properties, E6
wave theory of light, E6
wavelength, measurement of, E6
waves
localization of, Q8
superposition of, Q8
waves and particles, Q1, Q5
weak force, G8
weight, M7
Wheeler, John
and geometrodynamics, R11
and momenergy, R8
and naming of Planck length, G6
and theory of fission, N6
Wilson, William, Q2
work
definition of, M12
and heat, T2, T8
relationship to kinetic energy, M12
world-line diagrams, Q16
Wren, Christopher, M13

Young, Thomas, E6

Z particle, G8