French physicist Jean-Pierre Christin published the design of a mercury thermometer using the centigrade scale with 0 representing the melting point of water and 100 its boiling point.
Available at : Annales des sciences physiques et naturelles, d'agriculture et d'industrie
By Société d'agriculture, sciences et industrie de Lyon. via @googlebooks
In his paper Observations of two persistent degrees on a thermometer, Christin recounted his experiments showing that the melting point of ice is essentially unaffected by pressure. He also determined with remarkable precision how the boiling point of water varied as a function of atmospheric pressure. He proposed that the zero point of his temperature scale, being the boiling point, would be calibrated at the mean barometric pressure at mean sea level.
Historical note:
1742 Anders Celsius invented the Celsius temperature scale. In its original form the scale had 0 degrees for the boiling point of water and 100 degrees for its freezing point.
1743 The scale was changed by Jean Pierre Christin so that 0 degrees is the freezing point of water and 100 degrees is its boiling point.
English self-taught mathematician and physicist Oliver Heaviside was born #OTD in 1850.
He invented a new technique for solving differential equations, independently developed vector calculus, and rewrote Maxwell's equations in the form commonly used today. He significantly shaped the way Maxwell's equations are understood and applied in the decades following Maxwell's death. His practical experience in telegraphy provided a foundation for his later theoretical work.
British mathematician, logician, philosopher, & public intellectual Bertrand Russell was born #OTD in 1872.
One of Russell's most significant achievements is the co-authorship of "Principia Mathematica" (1910-1913) with Alfred North Whitehead. His works, such as "The Problems of Philosophy" (1912) & "Our Knowledge of the External World" (1914), explored issues related to knowledge, perception, & the scientific method.
"Physics is mathematical not because we know so much about the physical world, but because we know so little: it is only its mathematical properties that we can discover."
An Outline of Philosophy Ch.15 The Nature of our Knowledge of Physics (1927)
"The pursuit of philosophy is founded on the belief that knowledge is good, even if what is known is painful."
My PhD thesis has been published!
If you're interested in how to manipulate atoms into their coldest possible state using lasers, and why it's interesting to drop them in a 10m vacuum tower, this is for you! Also, fun with "painting" arbitrary shapes with laser beams! #physics#AtomInterferometry#Quantum#QuantumSensing https://doi.org/10.15488/17346
This is quite interesting. (no... really!) I recently persuaded a colleague to take my pet Geiger counter from Dunedin to Apia via Auckland. The latitude dependency of the radiation exposure is fascinating! #radiation#NewZealand#physics
A massive cotton candy-like exoplanet stumps astronomers.
@popsci reports on a new study from Nature Astronomy: "Despite being 50 percent bigger than the gas giant Jupiter, exoplanet WASP-193b is seven times less dense."
The “Astrophysical and Cosmological Relativity” department at the @mpi_grav in Potsdam announces the opening of several postdoctoral appointments.
These appointments will be in the area of data analysis and its interface with waveform modeling for the recently adopted space-based gravitational-wave detector LISA.
American physicist Richard Feynman was born #OTD in 1918.
He developed the Feynman diagrams, a pictorial representation of the mathematical expressions governing the behavior of subatomic particles, which provided a powerful tool for calculating complex interactions among particles. He received the Nobel Prize in Physics in 1965 jointly with Julian Schwinger and Shin'ichirō Tomonaga for their fundamental contributions to the development of quantum electrodynamics (QED).
In addition to his research contributions, Feynman was known for his exceptional teaching ability & engaging lectures. He authored several popular science books, including "Surely You're Joking, Mr. Feynman!" & "What Do You Care What Other People Think?" Many of his lectures & miscellaneous talks were turned into other books: The Character of Physical Law, QED: The Strange Theory of Light and Matter, Statistical Mechanics, Lectures on Gravitation, & the Feynman Lectures on Computation.