Sound- The sensation felt be our ears is called sound
Examples of sound- The sound of television, The sound of music, The sound of our teachers, The sound of Birds Etc.
Wave– A wave is a vibratory disturbance which carries energy from one point to another without being direct contact with one another
Longitudinal waves– A wave in which the particles of the medium vibrate back and forth in the same direction in which the wave is moving is called longitudinal waves.
Example- When we pull a spring when it is pushed and pulled at one end,are longitudinal waves.
Compression- When the spring coils are pushed it is called compression
Rare-fraction– When the spring goes beyond its normal position after removing compression it is called rare fraction.
The Sound waves in air are longitudinal waves
Transverse waves- A wave in which the particles of the medium vibrate up and down at right angles to the direction in which the wave is moving is called transverse waves.
Examples- The waves produced by moving one end of a long (Slinky)up and down rapidly , whose other end is fixed, are transverse waves.
In transverse waves there is elevation or crest is that part which is above the line of zero disturbance
The depression or hollow or trough is that part of the transverse wave which is below the line of the zero disturbance