Einstein

Einstein published three major scientific papers. One of these put forward a new way of calculating the size of molecules. Another explained Brownian motion - the random dance performed by specks of dust trapped in a fluid. Einstein suggested that the tiny particles making up the fluid - its atoms or molecules - were bouncing against the specks of dust and causing the motion. These papers helped to establish the reality of atoms and molecules. Einstein’s paper on the photoelectric effect helped give birth to quantum theory, and it was for this paper that Einstein received the Nobel Prize in 1922. Quantum theory led, in the 1920s and 1930s, to another revolution in physics. Physicists showed that, as well as light waves behaving like particles, particles could sometimes act as waves. This theory established “objective probability” in physics. This was the idea that completely unpredictable chance events can take place at the subatomic level. Einstein never fully accepted the prevalent interpretation of quantum theory. But, while many of these interpretations involve wild metaphysical flights of fancy, the physical results are, like those of relativity, very well established. Marrying together the two pillars of 20th century physics - relativity and quantum theory - is a central problem for physics even today. Successfully doing this may require a revolution in science similar to those begun by Newton and Einstein. Changes in technology can make new experiments possible and they also influence the problems that scientists develop an interest in.