History of Science Midterm 1

In the beginning there was time and there was space. Classical physics saw these as absolute. Any two observers from any frame of reference could synchronize their watches and agree on the exact moment that an event occurs. Albert Einstein disagreed. Working in his spare moments in the patent office, Einstein developed new ideas. Einstein's special theory of relativity and its treatment of time have revolutionized science, technology, as well as the popular culture.

Einstein proposed in his theory that there is only one absolute, the speed of light, and that distance and time are relative, meaningful only when associated with a particular frame of reference. Einstein worked only with numbers and formulas, doing no experimenting of his own. Einstein played mind games, exploring with thought rather than hard data.

For this and other reasons, scientists were skeptical of Einstein's theory. Absolute time had been a given. Given Einstein's lack of experience, and with the weight of classical physics on their side, how could scientists accept Einstein's new ideas? The answer was through experiments. Einstein's theory predicted that high speed muons would have an extended existence due to their high speed, a phenomenon known as time dilation. Experiment proved Einstein correct. When atomic clocks were developed, able to count very small increments of time, it was shown that the gravitational difference between airborne and ground clocks resulted in time dilation for the clocks aboard aircraft.

In addition to the experiments, other young brilliant minds at work in science were more willing to embrace Einstein's theory. These men had not been as rigit in their hold to classical physics as other older scientists were. These young scientists examined Einstein's ideas and developed them further. The theory of space-time, the four-dimensional conglomeration of the three "physical" dimensions and time, was just one of these new ideas.

Einstein's treatment of time has applications beyond just theories and ideas. The very fact that time is dilated at high speeds allows particle accelerators to work; particles would otherwise vanish before detection. Even today's sophisticated global positioning system requires compensation for time dilation effects. Were it not for Einstein's theory, these and other technologies would not be possible.

No less important is the effect Einstein's work has had on popular culture. Here Einstein has left an indelible mark. Science fiction is filled with stories of time travel and space travel. Einstein also brought physics better into view for everyone, if not to understand, at least to accept.

The Photoelectric effect is the ejection of electrons from atoms of certain materials when light shines upon this. For example, a blue light shining upon a certain metal will cause an electric current to form. Scientists first thought it was the intensity of the light that mattered; they could not explain, therefore, why even an intense red light would not cause a current.

Einstein explained this effect using Planck's idea of quanta. Einstein proposed that light comes in quanta, discrete energy packets; the color of the light is a measure of the energy per packet. Blue light has high energy packets, and these packets would be absorbed by the electrons, giving them energy to leave the atom. Since these packets (photons) can only be absorbed individually, the less energetic red photons would have no effect on the electrons.

Robert Millikan was an American scientist. It was Millikan who first measured the charge on a single electron. He did this with his oil-drop experiment. Using small droplets of oil suspended between charged plates, Millikan used his observations of the differences of movements of the droplets between the plates to measure their charges. He found that most droplets had a charge of a multiple of a certain charge, and he found that no droplets had a charge below this. He therefore reasoned that this was a unit of charge, wich was then associated with the electron. It should be noted, however, that not all droplets had these integral charges, and that Millikan simply left this out of his published paper. he had dismissed these as bad data (correctly, in retrospect, but in effect he was lying by not providing all his data).

Brownian motion is the vibrational energy of all matter above absolute zero. Oftentimes described as a "drunken man's walk," Brownian motion describes the random movement of particles.

Originally this motion had been observed in pollen grains in water; at the time this motion could not be explained.

It was Einstein who reasoned that the motions of the pollen grains were due to collisions between the water molecules and the pollen.

Subsequent experiments were performed (one involving 1 micron latex globules in suspension), and these experiments agreed with Einstein's explanation. Many saw Einstein's explanation of Brownian motion to be the best proof for the existence of atoms.

Max Planck was a German scientist. He was very interested in the law of entropy, the second law of thermodynamics, and especially its application to solving the so-called "ultraviolet catastrophy" of black body radiation. Planck accidentally misused a statistical method when calculating the numbers for radiation, and to his surprise, it worked. Planck spent years working on the problem, even after he seemed to have solved it; he himself had doubts that his conclusion was correct, that energy can only be emitted in discrete packets, or quanta. Planck was not able to prove (to his disappointment) that entropy always increases, he did show that it does statistically increase.

The Michelson-Morely experiment was designed to prove the existence of ether, the medium through which light supposedly travels. Reasoning that the ether is all around, Michelson and Morely believed that one should be able to observe an ether wind as the Earth moves through the ether. They measured the speed of light in two directions; one of which they believed would be faster, because the light moved with the ether, the other slower, because the light moved against the ether. The experiment failed.

Einstein's special relativity dispelled with the need for ether. However it was not the Michelson-Morely experiment that spurred Einstein on with working out his theory, rather it was the assymetry of the ether theory. Einstein had presented special relativity as a more simple and harmonious alternative to the ether theory.

Return to Adamz Hoemwurk Paij.