What compact disc is made of

Digital sound recording on an optical disc.

• Clear polycarbonate disc — has part. A transparent disc with a track of pits.
• Reflective metal layer — has part. An aluminium coating reflects the laser.
• Protective lacquer layer — has part. A coating over the reflective layer.
• Binary number system — uses. Sound is recorded as numbers.
• Plastic — is made of. The disc is polycarbonate.
• Aluminium — is made of. The reflective layer is aluminium.

Compact disc

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