How DVDs and CDs store data?
Do you want to know how DVDs and CDs store data ?
Then read it buddies..
Earlier, we used to use video tapes to watch movies and cassettes to listen to music. However, times have changed! We now have compact discs or CDs, DVDs and such devices, as we fondly call them, to replace the cassettes and video tapes. As the name suggests, compact discs and Digital Versatile Disc are easy to handle and compact. They occupy very less place at our household and have better storage capacity. Let us find out how these DVDs and CDs store data and how they operate....
Everyday Chemistry - How DVDs and CDs Store Data?
Our parents used videotapes to watch movies and cassettes to listen to music but now, times have changed! We use compact discs, more commonly known as CDs as they are easy to handle and compact. They occupy very less place and have better storage capacity.
What are CDs and DVDs?
Compact discs (CDs) and Digital Versatile Disc (DVDs) use two main methods to store data and this depends on the volume of disks and works on the chemistry of Phase Change Materials.
DVDs and CDs use a mechanical process known as Precision Moulding. In this process, each "bit" which is a short form for "binary digit" is either an "up" or a bump or a "down" or a pit. Recordable DVDs or CDs use method known as Phase Change Materials that defines each "bit".
The Mechanical Processes of CD and DVD Data Storage
DVDs and CDs use a mechanical process which is called as Precision Moulding. In this process, each "bit" which is a short form for "binary digit" is either an "up" or a bump or a "down" or a pit. Recordable DVDs or CDs which are used by most of use follow the method called as Phase Change Materials which defines each "bit".
Why do CDs and DVDs use Phase Change Materials method?
The Phase Change Materials method that is used in DVDs and CDs help in converting these devices into a reflective or non-reflective material. The states "reflective" and "non-reflective" can be designated as a "0" or "1", in a recordable DVD or CD. Certain materials can be changed from reflective to non-reflective states, depending on their structure.
What Makes Phase Change Materials Reflective?
Phase Change Materials are more transparent when they are crystalline. It is usually larger and more regular crystals that are obtained by using a slower cooling rate, and hence it is done with the help of Phase Change Materials. This gives a crystalline structure to the Phase Change Material. To achieve a faster cooling rate, the material is then heated to a temperature higher than the melting point. This leads to a non-crystalline structure.
Where do I find Phase Change Material in CD's/ DVD's?
The DVD or CD has a Phase Change Material in the middle which is surrounded by dielectric layers. A reflective layer is above the Phase Change Material, so that the light produced by the reading device can be reflected back if it passes through the crystalline material. A detector then picks it up. The other layers are just there for protection.
So, the next time you see a CD or DVD, remember there is chemistry involved here as well!
Then read it buddies..
Earlier, we used to use video tapes to watch movies and cassettes to listen to music. However, times have changed! We now have compact discs or CDs, DVDs and such devices, as we fondly call them, to replace the cassettes and video tapes. As the name suggests, compact discs and Digital Versatile Disc are easy to handle and compact. They occupy very less place at our household and have better storage capacity. Let us find out how these DVDs and CDs store data and how they operate....
Everyday Chemistry - How DVDs and CDs Store Data?
Our parents used videotapes to watch movies and cassettes to listen to music but now, times have changed! We use compact discs, more commonly known as CDs as they are easy to handle and compact. They occupy very less place and have better storage capacity.
What are CDs and DVDs?
Compact discs (CDs) and Digital Versatile Disc (DVDs) use two main methods to store data and this depends on the volume of disks and works on the chemistry of Phase Change Materials.
DVDs and CDs use a mechanical process known as Precision Moulding. In this process, each "bit" which is a short form for "binary digit" is either an "up" or a bump or a "down" or a pit. Recordable DVDs or CDs use method known as Phase Change Materials that defines each "bit".
The Mechanical Processes of CD and DVD Data Storage
DVDs and CDs use a mechanical process which is called as Precision Moulding. In this process, each "bit" which is a short form for "binary digit" is either an "up" or a bump or a "down" or a pit. Recordable DVDs or CDs which are used by most of use follow the method called as Phase Change Materials which defines each "bit".
Why do CDs and DVDs use Phase Change Materials method?
The Phase Change Materials method that is used in DVDs and CDs help in converting these devices into a reflective or non-reflective material. The states "reflective" and "non-reflective" can be designated as a "0" or "1", in a recordable DVD or CD. Certain materials can be changed from reflective to non-reflective states, depending on their structure.
What Makes Phase Change Materials Reflective?
Phase Change Materials are more transparent when they are crystalline. It is usually larger and more regular crystals that are obtained by using a slower cooling rate, and hence it is done with the help of Phase Change Materials. This gives a crystalline structure to the Phase Change Material. To achieve a faster cooling rate, the material is then heated to a temperature higher than the melting point. This leads to a non-crystalline structure.
Where do I find Phase Change Material in CD's/ DVD's?
The DVD or CD has a Phase Change Material in the middle which is surrounded by dielectric layers. A reflective layer is above the Phase Change Material, so that the light produced by the reading device can be reflected back if it passes through the crystalline material. A detector then picks it up. The other layers are just there for protection.
So, the next time you see a CD or DVD, remember there is chemistry involved here as well!
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