Did Einstein make any inventions beside the atomic bomb?

Answer 1

Einstein's only involvement with the atomic bomb was to sign a letter written by Leo Szilard (the inventor of the atomic bomb, but Einstein didn't know this because the patent was classified and thus could not be discussed) that was addressed to FDR warning that the Nazis might be working on them. The US Military considered Einstein an enemy alien, so he could not have been granted a clearance to work on the project. Also Einstein was a complete pacifist and refused to do any war related work of any kind.

One thing that Einstein did invent was a refrigeration system with no moving parts, so it did not require any seals to prevent leaks. He did this because all the refrigerants available at the time were highly toxic and/or flammable making leaks very dangerous. However it saw little use at the time because not long after that freon was invented which was nontoxic and nonflammable. However his invention was used in the cooling systems of several nuclear reactor designs beginning in the 1950s.