Ronald Abramowski. age 12. of Milwaukee. Wisconsin.:
What is a cathode ray?
A cathode ray is a stream of tiny. particles. They are electrons bundles of negative electricity: In the cathode ray. they have been torn from the outer shells of atoms and directed at high speeds. Such a stream electrons can make all kinds of magic. depending upon how it is directed what it hits. If you have a TV set. you turn a cathode ray on and off in your own home.
A cathode ray can be made to produce Xrays Here it is directed to hit a hard substance. It can also be made to produce heat. A cathode ray is sometimes used to produce high temperatures for melting metals. And a cathode ray is used in radar. Here it is directed to force a substance to produce dots of light:
This is also the job of the cathode ray in your TV set. It works with the scanning tube. the iconoscope. to build up those moving pictures we love to watch. The special cathode ray tube in the TV set is called the kinescope.
The moving pictures. of course. begin in the studio at the broadcasting station. That is where the iconoscope does its part of the job. It copies the light and dark areas of the scene into tiny dots. Study a newspaper picture under a magnifying glass. You will see it is built up of large and. small dots. Large dots shade the dark areas. smaller dots record the lighter patches. The iconoscope works something like a photoelectric cell to build up such a picture. It scans over the whole scene 30 times each second.
Other equipment translates this scene into electrical impulses. The pattern is carried to the electric wires that bring it to your home. There the cathode ray is waiting in the TV set to do its job.
The kinescope is a large vacuum tube. It can change the electrical impulses back into dots of light. It can‑direct and gun them to build up exact copies of the picture being scanned by the kinoscope. miles and miles away. Pairs of metal plates in the narrow end of the cathode ray tube control and direct the stream of electrons to make pictures march over the TV screen.
The high speed electrons are gunned at a fluorescent material. This stuff is heavily coated on the inside of the large end of the kinescope: The electrons jostle the atoms in this material and force them to hop about. When hit hard. these atoms glow with light.
Like the iconoscope the kinescope also builds up pictures by scanning. It starts in the left hand corner. scans a line of dots. jumps back and starts a second row. It builds up the whole picture in the 30th part of a second. The complete pictures follow each other so fast that our eyes are deceived. We seem to be seeing action and movement. Actually we are seeing 30 different pictures every second. Only a stream of minute electrons from a cathode ray could do that wonderful job so well.