How does the television work when you press a button?

can then travel much larger distances.) The sound is then sent to the TV's loudspeaker. The picture signal is split into three separate colour signals; red, blue and green. If you look closely at a television screen you can see that the picture is made up of lots of horizontal lines. These lines are made up of tiny dots which glow red, blue or green. Your eye has three types of detectors - called cones - that react to these colours differently. There's a red cone that likes red light, a green cone that likes green light and a blue cone that likes blue light. When any colour enters your eye and hits these cones they send messages to your brain saying "I'm seeing red light" or "I'm seeing green light" or eve "I'm seeing a bit of blue and a bit of green". When the light from the dots on the television screen enters your eye, each cone sees each colour and sends a signal to your brain. Your brain then works out what colour it is supposed to be seeing from these signals. The screen itself is part of something called the picture tube. At the back of the picture tube are three electron guns (that fire electrons rather than bullets!) one for each colour. The electrons are shot out of the gun and hit the screen. These dots are made of phosphor, which glows when electrons hit it, the stronger the beam of electrons the brighter the glow. The three electron beams start in the top left corner and are moved across and down the screen, very very quickly. Each colour signal goes to one particular electron gun which excites just the dots of that colour, the signal tells the gun how strong it should be which in turn means some dots glow brighter than others. When you move back from the screen all the dots blur together (because they are so small) and the result is a TV picture. Your television receives a signal from a transmission tower and changes the signal into pictures and sound. Inside your television is a cathode ray tube which has three light guns in it (one’s for the colour red, one’s for green and one’s for blue) and they work like torches shining their light onto the inside of the screen (The screen is the part of the telly that you watch) The screen is made up of lots of dots and when the signal is received by the television it tells the guns what dot to shine their lights on. The coloured lights shining on the dots on the screen make up the picture that we see. Your television screen is coated with a stuff called phosphor that lights up when the light guns shine on it. The light that shines from the guns isn’t coloured - it’s the phosphor that’s coloured but the different lights make the phosphor colour glow. The picture on your television screen changes 25 times per second so those guns work really fast changing which dot they’re shooting light at.