IT USES PHOTONS!
There are 3 types of memory, optical, magnetic and solid state
Optical memory is the type of memory that CDs, DVDs, and Blueray discs use. It uses light rays to read tiny patterns engraved on the discs. It cannot store much however, with a DVD only being able to store 4.8GB of memory, and a CD only 702MB. It works in a similar way to a record but it uses light not a little scratchy thingy.
uses tiny magnetic toroids (rings), the cores, through which wires are threaded to write and read information, whatever that means. it uses magnetic fields to transmit information and if the field matches a pattern it is correct.
Solid state is the last form of memory, and is used most of the time. It includes physical objects like memory sticks, hard drives and floppy disks. anything with a physical property.