Abstract: Ultrasonics, a rapidly developing branch of acoustics, has many applications. Its practical applications such as nondestructive testing, cleaning, emulsification, medical diagnosis, surgery, therapy, etc. are all well known. Recent techniques for generating microwave phonons (10⁹c/s) and optical phonons (10¹²c/s) has made it a powerful tool in scientific research work both macroscopically and microscopically. The present paper outlines a few of its applications in the study of basic science with special emphasis on the solid states.