I was checking out the documentary about E=mc2 . The documentary attempts to bring to the fore the contribution of one of the greatest minds of the century, Albert Einstein, his equation relating mass, energy, and the speed of light. If we cut through the melodramatic presentation with the Victorian charms and the bourgeois society and its workings, rest of the documentary takes us through the most important developments that made Einstein's discovery possible. As Newton said 'standing on the shoulders of Giants', the documentary attempts to show the giants on whom Einstein stood to see farther than light, figuratively speaking.
The first important milestone happened to be the idea that various forms of energy though having an existence independent of their own, are inter-related and can be changed from one form to another. Heat in the steam, and electricity in the wire, and magnetism of the magnets were all examples of energy in the pristine form, all having a common undercurrent: "energy". Michael Faraday showed that electrical energy can be used to create magnetism in objects and vice versa. The theory of electro-magneitc waves and electromagnetic field came to be proposed for the first time.
The debate that then ensued was about the conservation of matter. That it can neither be created nor be destroyed. It was shown by Antoine Lavoisier, assisted by his wife Marie Anne, that water can be converted to steam, then passed through iron and then condensed at the other end. The liquid at the other end is water, but is lesser in mass than initial. The hydrogen gas collected along with the water in the container and the rust that had formed by reaction between iron and oxygen accounted for the missing mass.
The next crucial part was that energy was proportional to the square of the velocity. It was shown by a Dutch scientist that when a lead ball is dropped on to a box of clay, it makes 4 times deeper impression when dropped from twice the height. Thus providing evidence to the squared relation, though it went against the proposals of Newton at that time. It took a century to gain general acceptance among the scientific community. Major headway in these episodes was played by Gottfried Leibniz and Emilie du Chatelet. Emilie du Chatelet lead a prolific role in science apart from excelling in arts, and raising a family of 3 children. She translated the Newton's Principia in French.
We are then taken back to Faraday who had then proposed that light itself as a form of energy and hence an electromagnetic wave. It caused much furor as people were still grappling with the idea of the mysterious interplay between Electricity and Magnetism that Faraday himself had demonstrated earlier. Maxwell came along to show that mathematics did permit such a possibility. But then Maxwell also suggested that, to be consistent with his theory, even if one were to travel at the speed of light (690 million mile per hour), one would observe light traveling at the 690 million mile per hour away from them. If you travel next to a car at the same speed as that car, that car would then appear stationary to you. The proposal was counter-intuitive.
Einstein for his part, had to reconcile this fact. He realized that this is possible if the hands of the clock were to move slowly at higher speeds. Thus time was no more independent of the space, measured in watches. Space and time were now related. This dealt an incredible blow to 3 centuries of resolute faith in the scientific belief that time was an absolute.
Einstein began to wonder, what would happens if train were to be accelerated to the speed of light, and more fuel were added to it to accelerate it further? Will it travel at a speed greater than light? That's not possible. So, he concluded that the added energy must be converted to mass of the train to conserve energy.
Thus it allowed him to derive the relation between energy, mass, and velocity of light. E=mc^2
The documentary then goes on the show the meteoric rise of Einstein among the ranks and his proposal for special and general relativity of which a nice introduction can be found on shallowthgts.
So definitely get hold of the documentary and see it. You will learn about women who played very important role in science and have remained relatively unknown. You also get to see the coming together of important scientific developments, each one a truly great milestone.
(an updated repost from the past)