Holography is the method of producing a three-dimensional image, called a hologram. A hologram is created by first splitting a laser beam. Half the beam is recorded on a plate, unaltered, and the other half is recorded after it is reflected off the object being imaged. On the recording plate, the two systems of light waves reinforce or neutralize one another, creating an interference pattern that, when illuminated by light of the same frequency, produces a hologram. Who invented holography?
Back in the day
Known as "the Edison Effect," thermionic emission is the emission of electrons or ions by substances that are highly heated. The charged particles that are emitted are called thermions, and their number rapidly increases with the temperature of the substance. If the heated substance that emits thermions carries a charge, the thermions will carry the same charge. The effect was observed by Edison in 1883 when he was working on what invention?
Born on a day like today
Banks was a British naturalist, botanist, and patron of the sciences. After inheriting a large fortune in his early 20s, he began traveling extensively, collecting plant and natural history specimens. He outfitted and accompanied James Cook's voyage around the world, during which time he collected many biological specimens that had never before been classified. His herbarium, one of the most important in existence, and library are now at the British Museum. What plant genus was named after him?