Rational Thinker

Johannes Kepler had the relative sizes of the orbits of our planets in the solar system mapped by the 1630s. The shape of the solar system had been known relatively well, but it was a shape without scale. Determining the size of the solar system was a much more challenging problem, mainly because there was no known way to make such a measurement. However, that all changed with the development of parallax and taking advantage of an ...

In 1875, French chemist Paul-Émile Lecoq de Boisbaudran discovered the element 'Gallium' after isolating it from a zinc blende ore. However, shortly after his publication, he received word from a Russian chemist with the name of "Mendeleeff" that claimed he had predicted such an element to exist 6 years earlier. This is the story of how that Russian chemist - and a fellow German chemist - turned rival - uncovered the periodic law o...

Before the modern days of organic and inorganic chemistry, there was an old theory called "Vitalism" that had made its way into chemistry. Pioneered into the field by the one and only Jöns Jacob Berzelius, this theory postulated that only living things can create organic compounds through acts of the 'Vital Force.' But cracks in this theory started to form when his pupil, Friedrich Wöhler, synthesized a compound that is found in th...

For over two centuries, Newton’s law of gravity accurately predicted the motions of all the planets in the solar system. But that all changed in 1859, when French astronomer Urbain Le Verrier discovered a strange anomaly regarding mercury’s orbit. This led to a problem in Newton's reality that didn't have an answer until Albert Einstein proposed General Relativity in 1915. Einstein accurately modeled Mercury's orbit wit...

The 1920s were an era of intense discovery and progress in the world of physics. Concepts such as matrix mechanics, the Schrödinger model of the atom, the Heisenberg uncertainty principle, and more dominated this era of progress. All of these concepts had a particular trait in common with one another: they showed that probability was the driving force behind reality. Many physicists, most notably among them, Albert Einstein, were n...

In 1895, German physicist Wilhelm Conrad Röntgen discovered a new type of radiation. It was invisible and penetrating to some materials, but not others. He called the radiation "X-rays," and the phenomenon took over the science world. The very next year, a French physicist named Antoine Henri Becquerel, while studying these rays and trying to link them to phosphorescence, accidentally stumbled upon a new phenomenon that would ultim...

The gravitational constant, or at least what it represents, is a fundamental part of our universe. It represents the strength of gravity and, to our knowledge, remains unchanged throughout space and time. But how did our knowledge of this come about? It all started with the Principia, but Newton did not introduce the constant G. This video takes you through the historical process of discovering G and integrating it into the science...

The first liquefaction of helium in 1908 by Dutch experimental physicist Heike Kamerlingh Onnes was revolutionary. For the first time, scientists could push the boundaries of extremely low temperatures and see what happens to materials. 3 years after that feat, Onnes wanted to test something new: what happens to a metals electrical resistance as you reach those critical temperatures? 3 theories existed before Onnes tackled the prob...

After the discovery of beta radiation by Ernest Rutherford in 1898 and the formulation of the mass-equivalency relation by Einstein in 1905, scientists realized that beta radiation was behaving in an odd way. The expected kinetic energy of the beta particles was less than expected and spread out over a spectrum as opposed to the expected single value. Some thought energy conservation was being violated, but a few scientists thought...

The weights of atoms and molecules are quite precise today, but has quite a long and complicated history. This video dives into the very beginning of that history, right when modern atomic theory was beginning to surface. John Dalton is the inventor of relative atomic weight, and his ideas were instrumental in getting atomic theory off the ground and running. Not only does this video cover Dalton's contribution, but also two scient...

In the 1780s, an Italian physicist named Luigi Galvani made a shocking discovering when experimenting with the remains of frogs. He found that when he touched a the nerves of a frog with a lancet, and at the same time, discharged electricity from an electrostatic machine nearby, the frog legs would kick. This would spark a century-long slew of discoveries and theory that would eventually lead to the discover of the invisible radiat...

In 1887, physicists Albert Michelson and Edward Morley discovered a new phenomenon that would come to be known as the fine structure of spectral lines. These spectral lines split into two or more components, and other effects like the Zeeman and Stark effects also showed cases where spectral lines split. The quest to answer why this happened took almost 40 years and would end with the discovery of a new characteristic of an electro...

In the 1770s, a revolution in chemistry had just begun, starting in Uppsala, Sweden. A young apothecary named Carl Wilhelm Scheele began a series of experiments that led to the eventual downfall of an entire theory of fire that had dominated chemistry for a century. This theory was known as the theory of phlogiston; phlogiston was an invisible substance that released from materials when they burned and was absorbed by air or other ...