Although the optical discs are all 5 ¼”, a CD drive can not read a DVD disc, and a DVD drive can not read a Blu-ray disc. Why not? (Hint: research - pits, lands, and laser beams)

For storing the data into a CD, we need to burn it. And the surface of the CD is comprised of the polycarbonate layer that is molded as the spiral tracks over the surface of the CD. And the Data is being stored as a sequence of minute grooves that are called the pits which are encoded on the spiral tracks. And the region in between the pits is known as lands.

The DVD or the digital video dos is based on the optical data storage which is almost the same as the CD. The analog data is transformed into the digital data, and this is encoded on the disc starting from the inside edge, and towards out. This digital information is being encoded into the surface as pits, and the surface acts as the recording layer. A DVD can hold data up to 4.77 to 8 GB.

Since DVD size is bigger than CD, A DVD drive can read CD, but the CD drive cannot read the DVD,

And unlike the above two, which make use of the red laser for reading and writing, the blu ray makes use of the blue laser. Also, it has the smaller pits, tiny beam as well as small track that together make it possible to store around 25 GB of data in one single blue ray disc. And this is five times more than the size of a DVD.  

The Blu ray Discs are good for playing the CD as well as DVD. However, the opposite is not possible due to the size.

Explanation:

Please check the answer section.