Answer:
Unlike hard disks, which use magnetic charges to represent 1s and 0s, Compact Disks, DVD's or Blue Rays use reflected light.
Step-by-step explanation:
The way CD's work is that they are hit by a laser beam which is reflected on the surface of the disc. These disks have some valleys and mountains that reflect light differently so the CD player will interpret these differences in reflection as data which will then be turned into music, videos or computer files.