One of the most interesting developments in the history of chemistry has been the way in which theories of valency have evolved over the years. We are rapidly approaching the centenary of G.N. Lewis’ 1916 article in which he proposed the simple idea that a covalent bond consists of a shared pair of electrons.
The history of modern Crystallography is intertwined with the great discoveries’ of William Lawrence Bragg (WLB), still renowned to be the youngest Nobel Prize in Physics. Bragg received news of his Nobel Prize on the 14th November 1915 in the midst of the carnage of the Great War. This was to be shared with his father William Henry Bragg (WHB), and WHB and WLB are to date the only father and son team to be jointly awarded the Nobel Prize.
In the same way as a jungle harbours several species of birds and mammals, the stellar (or almost stellar) zoo also offers a variety of objects with different sizes, masses, temperatures, ages, and other physical properties. On the one hand, there are huge massive stars that easily overshadow one as the Sun. On the other, there are less graceful, but still very interesting inhabitants: small low-mass stars or objects that come out of the stellar classification. These last objects are called “brown dwarfs”.
For some people, recent images of the Rosetta space program have been slightly disappointing. We expected to see the nucleus of the Churyumov-Gerasimenko comet as a brilliantly shining body. Instead, images from Rosetta are as black as a lump of coal. Galileo Galilei would be among those not to share this sense of disappointment.
In 1980, Walter Alvarez and his group at the University of California, Berkeley, discovered a thin layer of clay in the geologic record, which contained an anomalous amount of the rare element iridium. They proposed that the iridium-rich layer was evidence of a massive comet hitting the Earth 66 million years ago, at the time of the extinction of the dinosaurs. The Alvarez group suggested that the global iridium-rich layer formed as fallout from an intense dust cloud raised by the impact event.
Light occupies a central place in our understanding of the world both as a means by which we locate ourselves in nature and as a thing that inspires our imagination. Light is what enables us to see things, and thus to navigate our surroundings. It is also a primary means by which we learn about the world – light beams carry information about the constituents of the universe, from distant stars and galaxies to the cells in our bodies to individual atoms and molecules.
American consumers have increased their purchases of artisanal foods in recent years. Grant McCracken, an anthropologist who reports on American culture and business, identifies ten concepts that the artisanal movement is composed of and driven by. These include preferences for things that are handmade, on the human scale, relatively raw and untransformed, unbranded, personalized […]
The business of condensed-matter physics is to explain why the world appears as it does to our naked eyes. This is a field lacking the glamour of high-energy physics or the poetry of astrophysics. The general public is quick to forget that smartphones owe much to the manipulation of electron herds in the Silicon Forest and the quantum theory of solids.
One of the central concepts in chemistry consists in the electronic configuration of atoms. This is equally true of chemical education as it is in professional chemistry and research. If one knows how the electrons in an atom are arranged, especially in the outermost shells, one immediately understands many properties of an atom…
In the popular imagination, science proceeds with great leaps of discovery — new planets, new cures, new elements. In reality, though, science is a long, grueling process of trial and error, in which tantalizing false discoveries constantly arise and vanish on further examination. These failures can teach us as much — or more — than its successes.
The periodic system, which Dmittri Ivanovich Mendeleev presented to the science community in the fall of 1870, is a well-established tool frequently used in both pedagogical and research settings today. However, early reception of Mendeleev’s periodic system, particularly from 1870 through 1930, was mixed.
The International Year of Light provides a good opportunity to revisit the early studies on the optical properties of X-rays. X-rays were discovered by W. C. Röntgen on the evening of 8 November 1895 while he was redoing some of Hertz’s experiments on cathode rays. By the end of the year, even before informing the world of his discovery, he had observed the basic properties of X-rays: like light, they propagate as straight lines and are diffused by turbid media, but are not deflected by a prism, nor refracted or reflected by matter; they pass through bodies, as shown by the radiograph of his wife’s hand.
One of the reasons that 2015 has been declared the International Year of Light is that it marks the 1000th year since the publication of Kitāb al-Manāẓir, The Treasury of Optics, by the mathematician and physicist Abu Ali al-Hasan ibn al-Hasan ibn al-Haitham, better known in Western cultural history as Alhazen. Born in Basra in present-day Iraq, he is acknowledged as the most important figure in optics between the time of Ptolemy and of Kepler, yet he is not known to most physicists and engineers.
Fin de siècle Hungary was a progressive country. It had limited sovereignty as part of the Austro-Hungarian dual monarchy, but industry, trade, education, and social legislation were rapidly catching up with the Western World. The emancipation of Jews freed tremendous energies and opened the way for ambitious young people to the professions in law, health care, science, and engineering (though not politics, the military, and the judiciary). Excellent secular high schools appeared challenging the already established excellent denominational high schools.
The periodic table has experienced many revisions over time as new elements have been discovered and the methods of organizing them have been solidified. Sometimes when scientists tried to fill in gaps where missing elements were predicted to reside in the periodic table, or when they made even the smallest of errors in their experiments, they came up with discoveries—often fabricated or misconstrued—that are so bizarre they could have never actually found a home in our current version of the periodic table.
Everything is connected. Animals and asteroids, bodies and stardust, heart valves and supernovas—all of these rise from the same origin to form the expanse of the universe, the fiber of our being. So say our guests of this month’s Oxford Comment, Karel Shrijver, an astronomer who studies the magnetic fields of stars, and Iris Schrijver, a physician and pathologist. We sat down for a captivating discussion with the co-authors of Living with the Stars: How the Human Body is Connected to the Life Cycles of the Earth, the Planets, and the Stars.