**Physics II Timeline: E&M**

**Julianna Evans**

**Magnetism**

**Modern Physics**

**Other**

**Electricity**

Benjamin Franklin (1752)

-electricity is not the result of friction

-theory of +/- electricity

-nature is always restored to equilibrium

-clouds are generally negatively electrified

Charles de Coulomb (1785-89)

-Coulomb's Law (electrostatic interaction between electrically charged particles.

-Inverse Square Law of attraction and repulsion of unlike/like magnetic poles

Alessandro Volta (1800)

-created devices that were able to store electric charge (first batteries)

-came up with methods to measure "electrical tension" (volts)

-constructed first electric battery

André Ampère (1820)

-first person to prove a connection between electricity and magnetism both theoretically AND mathematically

-laid the groundwork of electrodynamics (inspired by Hans Christian Oersted's discovery)

Georg Ohm (1827)

-the current flow through a conductor is directly proportional to the potential difference (voltage) and inversely proportional to the resistance

-Equation: I = EIR

Gustav Kirchhoff (1845, 1857)

-formulated his circuit laws

-calculated that an electric signal in a resistantless wire travels along the wire at the speed of light

-Law of thermal radiation

-collaborated with Robert Bunsen to discover Caesium and Rubidium

-spectroscopic work

Heinrich Hertz (1887)

-electricity can be transmitted in electromagnetic waves

-predicted the existence of electromagnetic waves and electromagnetic rdiation

-electromagnetic waves travel at the speed of light

-the velocity and length of electromagnetic (Hertzian) waves could be measured

-light and heat are electromagnetic waves

Robert Millikan (1908)

- oil-drop experiment

-measured the charge on a single electron (charge and mass values were unknown)

-charge is quantized, not a continous variable

-work on photoelectric effect

Hans Christian Oersted (1820)

-discovered that electric currents can produce magnetic fields (he placed a compass underneath a wire and turned on an electric current, which caused the needle to move)

Charles de Coulomb (1785-89)

-Coulomb's Law: deals with the electrostatic interaction between electrically charged particles

-Inverse square law of attraction of unlike/like magnetic poles

Michael Faraday (1821-1858)

-electromagnetic induction

-electromagnetic rotations

-the magneto-optical effect

-diamagnetism

-field theory, and more

Thomas Young

-interference

-single and double slits

Christian Doppler (1842)

-Doppler effect: the apparent difference between the freqency at which waves (sound, light) leave a source and that at which they reach an observer

-magnetic declination over time

**Light**

**Sound**

**Molecules**

Albert Michelson

-contribution to the Michelson-Morley experiment

-establishment of the speed of light as a fundamental constant

-spectroscopic and metrological investigations

-measured the diameter of betelgeuse

E. W. Morley

-contributed to the Michelson-Morley experiment

-measured the speed of light as it passes through a strong magnetic field

-thermal expansion of solid materials

Albert Michelson and E.W. Morley

1887

-two beams of light, passed out and refleced back at right angles, which took equal amounts of time. They proved that stationary ether is FALSE

James Joule (1842)

-First law of Thermodynamics

-established the relationship between the flow of a current through a resistance and heat dissipation (Joule's Law -- basically the transfer of energy)

James Clerk Maxwell (1865)

-the faster molecules move, the more heat is generated (proportional relationship). Proves that heat is a movement of particle property (not a liquid moving from one thing to another)

-heat controls particle movement

-introduced the term "electromagnetic" and explained some of Faraday's theories mathematically (this helped J.J. Thomson discover the electron)

Johannes van der Waals (1878-80)

-discovered the existance of molecules (the existance of atoms was disputed at the time)

-molecules are of finite size and attract each other

-intermolecular forces => van der Waals force

-Law of Corresponding States

-Second law of Thermodynamics

-Capillary Theory

Wilhelm Roentgen (1895)

-discovered x-rays

-experimented with electric current flow in a cathode-ray tube

-discovered radiation (x-radiation)

-conducted research on: elasticity, capillary action of fluids, specific heats of gases, conduction of heat in crystals, absoption of heat by gases, piezoelectricity

J. J. Thomson (1894)

-discovered subatomic particles (electron)

-studied positively charged ions (positive rays)

-studied mass spectrometry

Pierre and Marie Curie (1898)

-pioneering work in radioactivity

-discovered the elements radium and polonium

-led to the understanding of the atom as something that can be split and release energy

Ernest Rutherford (1899)

-discovered a detector for electromagnetic waves (magnetizing coil containing tiny bundles of magnetized iron wire)

-studied the behabior of ions in gases, the mobility of ion with respect to the force of the electric field, photoelectric effect.

- 1899: Discovered two distint types of radiation emitted by thorium and uranium, which he named alpha and beta (distinguished by penetrating power)

- 1902: he found that radioactivity was a course of action in which atoms of one element spontaneously disintegrate into atoms of a completely different element, which also remain radioactive

- 1903: he named a type of radiation as gamma (greater penetration than alpha and beta rays)

-GREATEST CONTRIBUTION: his model of the atom in which a very small positively charged nucleus was orbited by electrons

Max Planck (1900)

-made contribution to theoretical physics

-fame rests primarily on his role as the originator of the quantum theory

-Along with Einstein's Theory of Special Relativity, it makes up the fundamental theories of the 20th century

-Studied thermodynamics, Planck's radiation formula, Planck's constant, new universal set of physical units (Planck length and Planck mass, which were based on fundamental physical constants)

Albert Einstein (1905)

-thesis on the different sizes and extent of molecules

-Photoelectric effect

-the transfer of light energy is an ongoing process

-The nature of radiations are that they are electromagnetic

-Einstein's Theory of Special Relativity (1905)

-General Theory of Relativity (1914)

Niels Bohr (1913)

-explained the atomic structure and studied quantum mechanics

-1913 model of atomic structure (became the basis of the famous quantum theory)

Karl Schwarzschild (1915)

-provided the first exact solution to the Einstein field equations of general relativity

-Came up with the Schwarzschild solution, which makes use of the Schwarzschild coordinates and the Schwarzschild metric, leads to the Schwarzschild radius, which is the size of the event horizon of a non-rotating black hole

Louis de Broglie (1924)

-groundbreaking work on the quantum theory

-wave nature of electrons

-all matter have wave properties

-wave-particle duality

-inspired the birth of wave mechanics

Werner Heisenberg (1925)

-contribution to quantum mechanics

-devised a method to formulate quantum mechanics in terms of matrices

-nuclear physics, particle physics, and quantum field theory

-uncertainty principle

Erwin Shrodinger (1926)

-one of the founders of quantum mechanics

-Shrodinger waves equation

-wave theory of matter

Enrico Fermi (1926-38)

-advancement of the first nuclear reactor

-contributions to quantum theory

-nuclear and particle physics, and statistical mechanics

-Fermi statistics (1926)

-discovered that slow moving neutron were particularly effective in producing radioactive atoms

Henry Bortoft (1938-2012)

-developed quantum physics

-came up with the topic of perception of wholeness

Maxim Chernodub (b. 1973)

-postulation of the magnetic-field-induced superconductivity of the vacuum (applications to astrophysics)

-came up with the theory that vacuum superconductivity in early universe caused large magnetic fields out in space

Lene Hau (b. 1959)

-was sucessful in stopping a beam of light with superfluids

-energy sciences with solar cells, nuclear power, batteries, and photosynthesis

Anatoliy Koroteyev (b. 1936)

-theoretical physicist and rocket engine physicist

-experimented with low temperature plasma

-created first high-power plasma torch

Roger Penrose (b. 1931)

-mathematical physicst, general relativity and cosmology

-Penrose-Hawking singularity theorems (with Stephen Hawking)

-Contributed with the second law of thermodynamics

-many geometrical-cosmological principles