Photoacoustic effect a rotating slotted wheel. He noticed that the resulting acoustic signal was dependent on the type of the material and correctly reasoned that the effect was caused by the absorbed light energy, which subsequently heats the sample. Later Bell showed that materials exposed to the non-visible (ultra-violet and infra-red) portions of the solar spectrum can also produce sounds and invented a device, which he called "spectrophone", to apply this effect for spectral identification of materials. Bell himself and later John Tyndall and Wilhelm Röntgen extended these experiments, demonstrating the same effect in liquids and gases. However, the results were too
The Invisible Man (1975 TV series) effect of his work is the ability to turn objects invisible, and tries to find medical applications for his invention. He discovers that objects that are made invisible reappear after a few hours, and on living test animals the collars they wear re-appear before the living cells themselves. Obsessed by his invention, Westin decides to become invisible himself, in part to prove that a human can survive the process, and also to test a serum he has developed to reverse the invisibility. He reveals the process to his boss, Walter Carlson (Jackie Cooper), who is initially unimpressed by what he