It’s so easy to grab a DVD from the shelf and pop it into your DVD player to watch a movie. But do you know what’s going on in your DVD player when you watch a movie? A lot!
While the vinyl record seems outdated and is old technology, it’s actually quite similar to when you place a disc in your DVD player and press “play”. In fact, picturing a record player’s needle “reading” the grooves in each record can help you visualize how a DVD player works.
The DVD player uses a laser – instead of a needle – to read the data imprinted in bits and bumps on the DVD. The laser in a DVD player is red, which is one of the key differences between a DVD player and a Blu-Ray player, whose laser is blue.
The laser reads the data by shining on the spinning disc and bouncing off every single little bump, reflecting onto an optical sensor. This sensor then deciphers an optical and audio signal which is what then plays as a film on your television and sound through your speakers.
DVDs are made of polycarbonate plastic – the same plastic used in manufacturing water bottles and sunglasses. The data on the DVD is imprinted in a spiral shape, moving from the centre of the DVD to the outside of the disc.
The laser in a DVD player is so precise, it can read the data on the DVD – which is composed of pits and bumps that are only 320 nanometers across. The data on the DVD is so small, that if you were able to straighten out the spiral on just one DVD it be more than 12 kilometers long!