Is there any way by which PS I can be modified to play PS2 games?

[Kendomon]

A PS2 is a DVD drive, a DVD disk can hold 12 CD's on them. Your PS1 is a CD drive, the lens can not read the small lines of a DVD so it will not be able to read the PS2 DVD games. Most PS2 games that aren't DVD are a different CD format then the standard for Ps1 it'd be like putting a Dreamcast game in your playstation and trying to play it, it's not gonna happen.