Today in History – April 24, 1877 – Brush patents first dynamo or electric generator. The dynamo was a concept that had been built earlier by Faraday, Henry and Pacinotti and Gramme and concurrently by Edison, but Brush’s more efficient dynamo got the U.S. patent. Brush’s dynamo eventually became the workhorse of the electric power [...]

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Today in History – April 23, 1867 – Zoetrope is patented. Before we had movies, there were a number of devices that took advantage of the “persistence of vision” in using flashing still images to simulate moving images. The zoetrope did this by putting the images on a strip of paper  inside a cylinder with [...]

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Today in History – April 22, 1970 – First Earth Day. Senator Gaylord Nelson, founder of Earth Day, says that the idea for Earth Day evolved over a period of seven years starting in 1962. He wanted President Kennedy to give visibility to pollution and the environmental degradation that was appearing throughout the country, but [...]

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Today in History – April 21, 1997 – Timothy Leary and Gene Roddenberry launched into orbit. LSD guru Timothy Leary and “Star Trek” creator Gene Roddenberry (left image) hitched a ride into space, along with 22 other people as part of a new commercial “memorial space flight” venture of Texas-based Celestis Inc. The Spanish Pegasus [...]

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Today in History – April 20, 1940 – RCA Demonstrates Scanning Electron Microscope (SEM). The history of the SEM begins in 1928 and RCA’s demonstration in 1940. In 1965 the first SEM was marketed by the Cambridge Instrument Company. The provided link includes an article that details the history of the SEM from 1928 to [...]

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