19th Century Flashcards
Nicolas Leonard Sadi Carnot
1796-1832
The Father of Thermodynamics.
Newcomen and Watt style engines were widespread. Carnot developed working theory.
He still saw things through paradigm of caloric theory: the difference in temperature between two bodies, warm and cold, enables transfer of caloric; this is the motive power of heat.
Heat is useless without cold.
The greater the temperature difference, the greater the motive power. Like a waterfall.
Conceptualized the hypothetical ideal engine, ideal heat pump, and supra-ideal pump, which would be a perpetual motion machine—an absurdity.
Carnot cycle.
Reflections on the Motive Power of Fire.
James Prescot Joule
1818-
Studied with John Dalton.
Started work at family brewery, pumps, vats, temperature, steam machinery. Tried to apply electric motors to do some of the work.
Noted electric current heats a resistance wire. Current produced by wire coil in dynamo. But, putting the dynamo in water tube, found that the dynamo coil gets hotter too, so it is not pumping caloric into the resistance wire, otherwise the dynamo coil would be getting cooler. Therefore, results gainsay the veracity of caloric theory. Thus, the ultimate source of the heat in wire was the work done on the dynamo.
Electricity can be converted to heat, with a mathematical relationship (Heat produced, the current, and the resistance of the wire). Coal and steam power was still cheaper at the time.
Used falling weight to turn a paddle in a tub of water, quantified the relationship between work done and heat produced in the tub of water (without electricity as intermediary). Also the amount of heat needed to raise a given mass of water by a given degree of temperature.
“Grand agents of nature.” ==> “Energy.”
Hermann Ludwig Ferdinand von Helmholtz 1821 – 1894
Thermodynamics, Mechanics, Physiology
Discovered the principle of conservation of energy while studying muscle metabolism.
He tried to demonstrate that no energy is lost in muscle movement, motivated by the implication that there were no vital forces necessary to move a muscle.
Postulated a relationship between mechanics, heat, light, electricity and magnetism by treating them all as manifestations of a single force (energy in modern terms[7]).
In the 1850s and 60s, building on the publications of William Thomson, Helmholtz and William Rankine popularized the idea of the heat death of the universe.
William Thompson 1824 - 1907
Electrical theory.
First and second laws of thermodynamics, formulation. Read Sadi Carnot.
Extrapolated to age of earth (initially 20 - 400 million yrs, later 20 - 40 million), and heat death of universe.
President of Royal Society 1890 - 1895
Knighted for work on the transatlantic telegraph.
Proposed absolute temperature scale.
Vortex theory of atoms.
Believed in lumiferous aether that propogated light waves.
Willard Gibbs 1839 – 1903.
Invented vector analysis and founded the sciences of modern statistical mechanics and chemical thermodynamics.
This work lies at the heart of physical chemistry, telling us which chemical reactions are feasible.
Statistical mechanics allows physical phenomena to be explained and calculated by averaging the individual behaviors of huge numbers of atoms/molecules.
Gibbs Equation of State – now a basic equation of thermodynamics: dU = TdS – PdV
J. J. Thomson
Lived 1856 – 1940.
In 1897, age 40, Thomson carried out a now famous experiment with a cathode ray tube. Allowed his cathode rays to travel through air rather than the usual vacuum and was surprised at how far they could travel before they were stopped. This suggested to him that the particles within the cathode rays were many times smaller than scientists had estimated–smaller than atoms! Atoms no longer indivisible. Subatomic particles exist.
Proposed the plum pudding model.
Cathode rays degree of deflection by magnetic or electric fields measured the mass. Applied this to other ionized particles and invented mass spectroscopy.
Heinrich Hertz
1857 – 1894.
In a series of brilliant experiments Heinrich Hertz discovered radio waves and established that James Clerk Maxwell’s theory of electromagnetism is correct.
Hertz also discovered the photoelectric effect, providing one of the first clues to the existence of the quantum world. The unit of frequency, the hertz, is named in his honor.
Marie Curie 1867 – 1934.
Polish.
Only person who has ever won Nobel Prizes in both physics and chemistry. First woman to be awarded a Nobel Prize.
1895 Married Pierre (piezoelectricity, magnetism, Curie point).
Uranium rays charge the air and make it conductive.
The uranium minerals pitchblende and torbernite have more of an effect on the conductivity of air than pure uranium does. She theorized correctly that these minerals must contain another chemical element, more active than uranium.
First discovered polonium, named by Marie to honor her homeland. 300 times more radioactive that uranium.
Discovered radium, named after the Latin word for ray. Several million times more radioactive than uranium., compounds are luminous, radium produced heat continuously.
Together they came up with a new word: radioactivity.
Atoms are not stable, but break up into subatoms!
Founded Curie Institu to treat tumors with Radium.
Died of aplastic anemia.
Max Planck 1859-1947.
German. Studied thermodynamics of Helmholtz and Clausius.
1879, doctoral thesis concerning the second law of thermodynamics – summa cum laude.
Mismatch between the wavelengths radiated by hot objects and the wavelengths predicted by classical theories of thermodynamics.
Planck’s proposed that only certain amounts of energy could be emitted – i.e quanta (Classical physics held that all values of energy were possible). This was the birth of quantum theory. Planck found that his new theory, based on quanta of energy, accurately predicted the wavelengths of light radiated by a black body.
Planck found the energy carried by electromagnetic radiation must be divisible by a number now called Planck’s constant, represented by the letter h.
Energy could then be calculated from the equation: E = hν where E is energy, h is Planck’s constant, and ν is the frequency of the electromagnetic radiation.
Planck’s constant is a very, very small quantity indeed. Its small size explains why the experimentalists of the time had not realized that electromagnetic energy is quantized. To four significant figures, Planck’s constant is 6.626 x 10 E-34 J s.
David Hilbert 1862-1943.
German mathematician and one of the most influential mathematicians of the 19th and early 20th centuries. Hilbert discovered and developed a broad range of fundamental ideas in many areas, including invariant theory, the calculus of variations, commutative algebra, algebraic number theory, the foundations of geometry, spectral theory of operators and its application to integral equations, mathematical physics, and the foundations of mathematics (particularly proof theory).
Jules Henri Poincare 1854-1912
French mathematician, theoretical physicist, engineer, and philosopher of science. “The Last Universalist” The three-body problem, laid the foundations of modern chaos theory. One of the founders by of the field of topology. Poincare conjecture about 3-sphere, hyperdimensional sphere. Invariance of laws of physics under different transformations, and was the first to present the Lorentz transformations in their modern symmetrical form. Poincaré discovered the remaining relativistic velocity transformations and recorded them in a letter to Hendrik Lorentz in 1905. Thus he obtained perfect invariance of all of Maxwell’s equations, an important step in the formulation of the theory of special relativity. In 1905, Poincaré first proposed gravitational waves (ondes gravifiques) emanating from a body and propagating at the speed of light as being required by the Lorentz transformations. The Poincaré group.
Charles Babbage
1791-1871
English. Polymath, Mechanical engineer, inventor, philosopher, mathematician.
The father of the computer.
Designed mechanical Difference Engine (built 1991, Science Museum, London).
Analytical engine designed, programmed using punched cards, based on the Jacquard loom card belts.
