Cathode ray tube
The mid- to late-1800s was a period of scientific revolution, with physical processes such as electricity beginning to reveal their secrets. Early investigations into electricity led to the development of the cathode ray tube, which would eventually lead to the discovery of the electron, as well as to the invention of television.
Michael Faraday (1791-1867), noticed that after removing most of the air in a glass tube containing a cathode and anode, a faint glow could be seen between the positive and negative electrodes. Faraday's work was limited initially by the inability to create more than a partial vacuum.
Around 1855 German scientists Heinrich Geissler and Julius Plucker improved vacuum technology and were able to remove more of the air from inside such a tube. With the improved vacuum, Plucker was able to produce a much brighter glow between the electrodes. He was also able to demonstrate that the glow responded to the effects of a magnetic field.
English chemist and physicist William Crookes. (1832-1919) had already made significant discoveries before he turned his attention to vacuum tubes. Using his Crookes tubes, which created an even better vacuum than those of Geissler and Plucker, he showed that the "cathode rays" that cause the glow traveled in straight lines, causing phosphorescence upon striking certain materials. Crookes also installed tiny vanes that would turn in the tubes as the current was applied. He thought he had discovered a fourth state of matter- "radiant matter-but the true nature of this phenomenon had to wait until JJ Thompson's studies showed these particles to be subatomic
KINETOSCOPE
Motion pictures and even television may never have
become a reality if it were not for the creation of the Kinetoscope by Thomas Alva Edison (1847-1931) and his deputy William Dickson (1860-1935) in 1891. The idea of moving still frames in quick succession to give the illusion of a moving image had already been demonstrated. Edison and Dickson took the principle and built a machine that could show long rolls of film.
Edison was apparently inspired by a demonstration of the Zoopraxiscope, which used a fast-spinning disc with images around the outside to give the illusion of movement. Edison took it upon himself to develop a system that brought together moving images and sound; he called it the Kinetoscope. Edison set Dickson and his team to work on the project.
Edison and the team devised a system of printing images onto thin celluloid sheets cut into narrow rolls with perforated edges Sprockets that engaged with the perforations enabled the rolls to be fed at a uniform speed in front of a lit bulb. A shutter would flash light through the "film" at just the right time so that each image was exposed for an instant. When all
this was carried out at speed, the successive images
gave the illusion of movement
The final design of the Kinetoscope was unveiled in 1894 to great applause, the public was captivated by the invention. The initial peep-hole design of viewing led to the development of the projecting Kinetoscope. The work of Edison and his team led to the start of, the motion picture industry, and egtertainment was changed forever.
You must be logged in to post a comment.