Page 68 - Science Class 6 Times Publication

the vibrations in the water also. The water moves forming ripples
from the point where you are touching the water surface. These
ripples make waves.

Tuning fork Waves of water

Waves are produced in air as in water when source of sound vibrates
in air. Molecules of air move in such a way that molecules are tightly
arranged in some regions and loosely arranged in other regions. The
region where molecules are tightly arranged is called compression and
the region where molecules are loosely arranged is called rarefaction.

Compressions and rarefactions make a complete wave. In the form of
wave, sound travels from one place to another.

Sound wave

Sharpness of sound
Sound of guitar is different from sound of madal. Sound of a bird is
different from that of a buffalo. Sound of a small baby is different
from that of an adult person. Sound of guitar, bird and baby is sharp
whereas sound of madal, buffalo and adult is not sharp. Sound
having high pitch is sharp. Thin, small and tight objects produce
sharp sound.

Times' Crucial Science and Environment 64 Book 6