The difference between the DVD-R and DVD-RW is the presence of dedicated read and write laser circuitry .For further reading follow the link. Below are some of the part from the wiki
On read only media (ROM), during the manufacturing process the groove, made of pits, is pressed on a flat surface, called land. Because the depth of the pits is approximately one-quarter to one-sixth of the laser's wavelength, the reflected beam's phase is shifted in relation to the incoming reading beam, causing mutual destructive interference and reducing the reflected beam's intensity. This is detected by photo diodes that output electrical signals.
A recorder encodes (or burns) data onto a recordable CD-R, DVD-R, DVD+R, or BD-R disc (called a blank) by selectively heating parts of an organic dye layer with a laser[citation needed]. This changes the reflectivity of the dye, thereby creating marks that can be read like the pits and lands on pressed discs. For recordable discs, the process is permanent and the media can be written to only once. While the reading laser is usually not stronger than 5 mW, the writing laser is considerably more powerful. The higher writing speed, the less time a laser has to heat a point on the media, thus its power has to increase proportionally. DVD burners' lasers often peak at about 200 mW, either in continuous wave and pulses, although some have been driven up to 400 mW before the diode fails.
For rewritable CD-RW, DVD-RW, DVD+RW, DVD-RAM, or BD-RE media, the laser is used to melt a crystalline metal alloy in the recording layer of the disc. Depending on the amount of power applied, the substance may be allowed to melt back (change the phase back) into crystalline form or left in an amorphous form, enabling marks of varying reflectivity to be created.
Double-sided media may be used, but they are not easily accessed with a standard drive, as they must be physically turned over to access the data on the other side.
Double layer (DL) media have two independent data layers separated by a semi-reflective layer. Both layers are accessible from the same side, but require the optics to change the laser's focus. Traditional single layer (SL) writable media are produced with a spiral groove molded in the protective polycarbonate layer (not in the data recording layer), to lead and synchronize the speed of recording head. Double-layered writable media have: a first polycarbonate layer with a (shallow) groove, a first data layer, a semi-reflective layer, a second (spacer) polycarbonate layer with another (deep) groove, and a second data layer. The first groove spiral usually starts on the inner edge and extends outwards, while the second groove starts on the outer edge and extends inwards.
The reason why this has been upvoted may be that people have wondered about if you could make an "Audio DVD". – Oskar Skog – 2017-07-24T17:48:49.367
18Are you asking if you can burn a CD using a DVD burner? Or burn music to a DVD-R disc as if it were a CD and play it in a CD player? – Sandy Gifford – 2014-05-05T19:51:31.777
4@SandyGifford Or, as the question is currently stated, he might for all we know be asking if he could use the DVD-R disc itself to burn music to a CD-R. Not exactly great wording. – Schilcote – 2014-05-06T00:14:20.227
3Why has a question this unclear been voted up instead of being closed? – Tim S. – 2014-05-06T14:40:29.103
2I think it's about whether a DVD'R is actually a source of ignition... And if you could create flame from the DVD'R, the OP still wants the original functionality to remain. In the same way in the UK, the warnings on matches indicate fire can only kill children, the OP wants the same restrictive (or intelligent) type of flame to only seek CD's, destroy them so presumably DVD can rule supreme. – Dave – 2014-05-07T12:53:28.150