Science project copy

The element of my passion

By: Sujeeth Jinesh

The element of my passion

My hobby would be watching T.V. even though it may be like an epidemic in this country, I have always wondered what was inside a T.V. that makes it work.  I was curious about the screen because it displays such complex images with such ease that I wondered how it did that. So what is a T.V. made out of?

The T.V. itself.

It may be something that we use quite often and rely on for news and entertainment,  but there are elements like cadmium, mercury, lead and Yttrium in there which can harm health.

The screen is an amazing part of the T.V. that displays complex images with ease.  So what exactly allows these complex motions be made?

The T.V screen

The screen is basically made out of an ordinary glass like silicon.  But what is under that?  The T.V. screen is made up of tiny little pixels. But the entire screen is one single, big screen called a cathode ray tube.  A cathode ray tube is made up of a phosphor screen with metal and enclosed inside is a vacuum with two heating alloys and three electron guns.  The electron guns are for each of the basic colors which are Red, Green and Blue or otherwise known as RGB.  electricity goes through these alloys.  There is also a cathode inside which is like a negative electrode and an anode or a positive electrode.

Who made the cathode ray tube?

The original cathode ray tube was made by a British physicist named William Crookes around the year 1869-1875.  It was meant to be a discharge tube which you may know as signs with different elements giving off different lights for example hydrogen burns red.  It was called the Crookes tube.  It didn't have a phosphor screen until 1897 when it was modified by German physicist Ferdinand Braun.  It was then modified by a Russian scientist named Boris Rosing in the year 1907.  He added a fluorescent screen to it and made the screen the receiving end of a video signal which he sent to it.  The screen displayed a few simple geometric shapes which crowned it as the first ever television set.

What elements are in there?

Copper, Yttrium and Silver are also in the cathode ray tube.  These elements are added as impurities in the phosphor screen to make a different array of colors.  

Copper

Copper is added as an impurity to the phosphor screen to give off a greenish glow when electrons pass through the phosphor screen.  Copper are used as heat and electric conductors.  They are also used in pennies as a coating over the zinc inside or as wires.

Copper:(Cu),Transition metal,Group 11, period 4Origin is astronomical, not man made.

Yttrium

Yttrium is added as an impurity in the phosphor screen.  When it is struck by electrons it gives off a reddish glow. Yttrium in a pure form has no real uses but television.  But when compounded it can make propane for lanterns etc.  It is found naturally in plants and animals.  The total amount found in the body is about 0.5 milligrams.  Exposure to Yttrium can cause lung disease in humans.

Yttrium:(Y),Transition metal, Rare Earth metal,Group 3, period 5.Origin is astronomical, not man made.

Silver

Silver is added as an impurity in the phosphor screen.  When it is struck by electrons it gives off a bluish glow.  Silver is used as a precious metal and is found in jewelry, utensils and coins.   It is has the highest thermal and electric conductivity of any other metal.

Silver:(Ag), Transition metal, group 11, period 5.Origin is astronomical, not man made.

sources:http://inventors.about.com/od/cstartinventions/a/CathodeRayTube_2.htmhttp://en.wikipedia.org/wiki/Tvhttp://en.wikipedia.org/wiki/Cathode_rayhttp://en.wikipedia.org/wiki/Cathode_ray_tubehttp://en.wikipedia.org/wiki/Cathodehttp://www.hdtvuk.tv/bravia-d3000-series-lcd-hdtv.jpghttp://www.gayakuman.com/uploads/2009/03/samsung-un55b7000-led-tv.jpghttp://blog.broadcastengineering.com/brad/wp-content/uploads/2009/06/analog-tv.jpghttp://takebackmytv.com/pages/toxic_tvshttp://encyclopedia2.thefreedictionary.com/Cathode-Ray+Tubehttp://oss-spectrum.org/E.htmlhttp://science.jrank.org/pages/1274/Cathode-Ray-Tube-Display-screen.htmlhttp://environmentalchemistry.comhttp://www.jegsworks.com/Lessons/lesson5/crt.gif

The End.