Two main reasons are scratch damage and heat damage. Compact Disc is a 1.2 mm thick Polycarbonate transparent disc used for digital writing with the help of Laser beam. The poly carbonate plastic used in CD is Polymethyle Meta Acrylic. The surface of the CD is coated with a thin layer of aluminium to make it reflective, and is protected by a film of lacquer on top of the reflective layer, on which the label print is applied .In the CD, from the center outward there are areas like center (spindle) hole, the first-transition area (clamping ring), the clamping area (stacking ring), the second-transition area (mirror band), the information (data) area, and the rim. A standard CD has 120mm diameter and 15-20 gm weight. It can hold 80 minutes uncompressed (700 MB) data.
The writing side of the CD is polished on which the data is recorded as Bits (lands) and Pits (holes). Each pit is 100nm deep and 500nm wide and the pits are arranged spirally from the centre of the CD to its rim. Pits are formed during CD writing by burning the plastic with the help of pencil beam Laser. Pits are much closer to the label side of a disc, so that defects and dirt on the clear side can make the beam out of focus during playback. CD suffers more scratch damage on the label side. If the CD is exposed to heat, the lacquer coating melts and label detaches from the CD leaving small air gaps between the CD and label. This severely affects its working because the Laser beam passes out from the CD. Due to over use the dye’s physical characteristics may change, causing read errors and data loss.
Most people use shorthand language for sending SMS and in email chat. This popular short hand language is known as Internet Slang. With the introduction of computer based communication, the Internet slang words popularized because of its simplicity and time saving feature. The Slang involves the use of informal words and expressions which are not considered as the standard dialect. The origin of the Slang word has some connection with the Thieve’scant which are the broken words and codes once used by the thieves to convey their secret messages.
SMS is the fancy of young people especially students and the Mobile companies provide offers to increase its use as a trick to promote mobile use and to keep the users in their network. Unknowingly most people are in a state of Mobile addition. Slang words can influence our language expression, vocabulary etc to a certain extent. For verbal communication, we have two centres in the brain. The Wernicke centre is doing Language comprehension and the Brocas centre helps to express the language in the form of speech. When we read a sentence, the Wernicke centre conceives its idea and sends the information to the adjacent Brocas centre, which then helps to express the information in the form of speech.
If we use code words frequently, that may affect our language expression. If a child uses the code UR for sending messages frequently, he may pronounce YOUR as UoooR and sometimes he may write like this in examination. Experts say that heavy use of Codes and Slangs in internet and mobile phone may create problems in children to grasp the basic grammatical concepts and reduce their thinking and speaking ability. This also reduces the meaning of English and drops their ability to speak more phonetic.