Works of Hibat Allah Abu'l-Barakat al-Baghdaadi

Abu'l-Barakāt Hibat Allah ibn Malkā al-Baghdādī (1080 – 1164 or 1165 CE) was a scholar of the Arabic-Islamic tradition. He wrote Kitab al-Mu'tabar.

His Hebrew birth name was Nathanel, before converting from Judaism to Islam at some point in his life. He served the Saljuq sultan Ḡīāṯ-al-dīn Moḥammad Tapar (d. 511/1118) and wrote a treatise for him. The sultan accused him of treating him improperly and imprisoned him for some time.

Kitab al-Mu'tabar is based on a collection of notes on logic, physics and metaphysics that Abu'l-Barakat composed for himself; some of those notes were copied verbatim from works of other philosophers, notably Avicenna.

Abu'l-Barakāt in many respects followed Avicenna, but also developed his own ideas. He proposed an explanation of the acceleration of falling bodies by the accumulation of successive increments of power with successive increments of velocity, anticipating Newton's second law of motion.
Works of Hibat Allah Abu'l-Barakat al-Baghdaadi

Galileo Galilei and air pressure

Galileo is believed to have been one of the first to suggest an experiment that tested the relationship between the density of the liquid and the height of the column.

In 1640, Galileo conducted a suction-pump experiment at a pubic well together with his two assistants: Evangelista Torricelli and Giovanni Baliani.

He lowered a long tube into the well’s and from the well, Galileo’s tube draped up over a wooden cross-beam three meters above the well’s wall and then downs to a hand-powered pump held by two assistants. His assistants pumped the pump’s wooden handler, slowly sucking air out of Galileo’s tube, pulling water higher into the tube.

Galileo Galilei

They pumped until the tube flattered line a run-over drinking straw. In his Two New Sciences he noted that no matter how hard they worked water would not rise more than 9.7 meters above the well’s water level. It was the same in every test.

Galileo commented that a suction pump could not lift water more than 10 m so there appeared to be a limit to this abhorrence. Galileo realized that this had important consequences for suction pumps. Suction pumps do not ‘suck’ up water as was commonly thought.

He became satisfied that this was universal law of nature and that the rise of water to a certain height in pumps exhausted of air, was neither owing to nature’s horror of a vacuum or to the power of suction but to atmospheric pressure.

It is atmospheric pressure on the surface of the water that pushes water into the pump and to do this air must first be removed from the pump to create a vacuum – a process own as ‘priming’.

No very useful results, however were expected from this discovery, until at a later date, Torricelli adopted and greatly extended it.
Galileo and air pressure

Bragg’s Law by Lawrence Bragg

Bragg’s law is a diffraction effect expressed mathematically as nl=2d sinq in 1913 to describe the angles of incidence associated with X-ray reflections that occurs when parallel rays encounter crystal structures.

Bragg’s law is known after Sir Lawrence Bragg (1890-1971), who jointly with his father Sri William Bragg (1862-1942) won the Nobel Prize in Physics in 1915 for their work on the elucidation of crystal structures using X-ray diffraction.

The use of the term ‘reflection’ for a diffracted beam comes from the optical analog. In an optical mirror the angle of reflection is not restricted. Lawrence realized the principle by which X-rays can be used to reveal the arrangement of atoms in a crystal and he has spent his life using his technique ox X-ray crystallography to study the architecture of matter.

Bragg’s law and the study of diffraction have since been applied to many other theoretical and practical fields of study beyond X-rays and crystals.
Bragg’s Law by Lawrence Bragg

Discovery of Compton Effect by Arthur Holly Compton

This photon momentum was observed experimentally by Arthur Holly Compton (September 10, 1892 – March 15, 1962) in 1922, earning him the 1927 Nobel Prize in physics.

After he received his PhD in physics from Princeton University in 1916, Compton continued research at the University of Minnesota and at the Cavendish Laboratory at the University of Cambridge England.

In a paper presented to the AAAS in 1920 and published in the Journal of the Franklin Institute for August 1921, Compton not only asserted the electron is the elementary magnetic particle but also that its spin is quantized and may be the cause of the unexplained gyromagnetic anomaly found by Steward and Barnett.

Arthur Compton discovered that the wavelength of x-rays changes when they are elastically scattered by electrons, a phenomenon generally known as the Compton Effect.

He found that the rays would be divided into two lines or wavelengths, one line would be of one and the same wavelengths as the incident radiation, and the other would be the scattered rays of a longer wavelength.
Discovery of Compton Effect by Arthur Holly Compton 

Theory of big-bang

Big-Bang theory is the theory of the creation of the universe. The Big-Bang theory states that the expanding universe originated 10-20 billion years ago in a single explosive event in which the entire universe suddenly exploded out of nothing, reaching a pea sized super condensed state.

Georges Lemaître first proposed what became the Big-Bang theory in 1927 after he realized how neatly this fitted the nonstatic models of general relativity and formulated the theory of t expanding universe.

Edwin Powell Hubble’s discovery of the galactic red shift in 1929 was the significant development. It indicated that all galaxies were receding from each other as part of an expanding universe. The color change happens when objects are moving away, making lightwaves stretch out and change color.

The more distant the galaxies are the faster they are rushing away.

Also in 1920s, George Gamow worked with a group of scientists and suggested that elements heavier than hydrogen, specifically helium and lithium, could be produced in thermonuclear reactions during the Big-Bang.

In 1948, Gamow and his student Ralph Alpher wrote a paper on ‘The Origin of Chemical Elements’ one of many contributions to the Big-Bang theory that Gamow made and a key step to the modern understanding of nucleosynthesis.

More evidence of the Big-Bang came in the 1960s, when astronomers detected faint microwave radiation coming from every point in the sky.
Theory of big-bang

History and development of periodic table

The early Greeks thought that all material on Earth was constructed of a combination of four basic elements: earth, water, air and fire.

In the pre-Christian era the ancients knew only seven basic metals: gold (Au), silver (Ag), copper (Cu), lead (Pb), tin (Sn), iron (Fe), and mercury (Hg). Mercury was discovered last, about the 4th century BC.

The ancient knew about sulfur (S), but called it brimstone, and carbon in the form of diamonds and charcoal.

In 1669 a group of German chemists isolated phosphorus the first minerals element to be accurately identified.

On of the next major development, was due to Jeremias Benjamin Richter, who between 1792 and 1794 published a set of quantities that later became known as equivalent weights.

The periodic table was discovered in 1869 by as many as five or six individuals including Russian chemist Dmitri Mendeleev (1834-1907) at about the same times, following the rationalization of atomic weights at the Karlsruhe conference.

The periodic table of the chemical elements is organized as a matrix of rows of horizontal ‘periods’ that list the elements in their increasing atomic numbers and generally, according to their atomic weights.

The table was revised by British physicist Henry Moseley (1887-1915), who came up with the concept of atomic numbers, numbers based on the number of protons (positively charge particles) in an elemental atom.

The periodic table is a clean, crisp way of characterizing the elements, and if anybody are now or ever were a chemistry, physics or premed student, he can testify first hand to the of memorizing the information it provides.
History and development of periodic table

History of Quantum Mechanics

History of Quantum Mechanics
Quantum mechanics is the study of mechanical systems whose dimensions are close to the atomic scale, such as molecules, atoms, electrons, protons and other subatomic particles. Quantum mechanics is a most intriguing theory, the empirical success of which is as great as its departure from the basic intuitions of previous theories.

It is a fundamental branch of physics with wide applications. The foundations of quantum mechanics were established during the first half of the twentieth century by Werner Heisenberg, Max Planck, Louis de Broglie, Albert Einstein, Niels Bohr, Erwin Schrödinger, Max Born, John von Neumann, Paul Dirac, Wolfgang Pauli and others.

The history of quantum mechanics began essentially with the 1838 discovery of cathode rays by Michael Faraday, the 1859 statement of the black body radiation problem by Gustav Kirchhoff, the 1877 suggestion by Ludwig Boltzmann that the energy states of a physical system could be discrete, and the 1900 quantum hypothesis by Max Planck that any energy is radiated and absorbed in quantities.

According to the theorem proved by Gustav Kirchhoff in 1859 on the basis of the second principle of thermodynamics, the blackbody spectrum has a very remarkable property: It is a universal function of temperature only. In the 1877, Ludwig Boltzmann and Willy Wien restricted the form of this function by combining electromagnetism and thermodynamics. In the 1890s, spectroscopists working at Berlin measured it with the aim of determining an absolute standard for high temperature measurement. At the same time, the Berlin theorist Max Planck attempted a complete theoretical determination of the blackbody spectrum.

In 1905, Einstein computed the entropy of dilute thermal radiation from the high frequency limit of Planck’s law.

In 1913, Niels Bohr emphasized that mathematical symbols from classical mechanics permitted visualization of the atom as a minuscule Copernican system. Although suitably quantized laws of classical mechanics are used to calculate the electron’s allowed orbits, or stationary states, classical mechanics can neither depict nor describe the electron in transit.

In 1932 von Neumann put quantum theory on a firm theoretical basis. Some of the earlier work had lacked mathematical rigour, but von Neumann put the whole theory into the setting of operator algebra.

In 1933 Fermi develops a successful quantum field theory of beta decay. It describes how neutrons spontaneously change into protons and emit electrons and neutrinos.
History of Quantum Mechanics