SOUND

SOUND:The propagation of molecular vibrations through a material. Sound is generally associated with waves travelling through the air, but sound can travel through any material. Any longitudinal wave passing through a material can properly be referred to as a sound wave.
STEADY STATE THEORY: The theory that the universe exists in a steady state, unchanging. According to the steady state theory,the universe has always existed in its present condition. Although it enjoyed wide acceptance at one time,most scientists now believe that the universe has
not existed forever but had a beginning at a specific point in time known as the big bang. coming up