A boy on a hill A fires a gun. Another boy on hill B hears the sound after 4 s. If the speed of sound is 330 m s^-1, find the distance between the two hills.

Read the clues across and clues downwards and fill up the blank squares.

Across :

1. Sound travels in air in the form of …………… waves.
2. Hertz is a unit of …………… .
3. The sound heard after the reflection.
4. Higher the ……………, shriller the sound.

Down :

2. Bat can produce …………… waves.
3. Sound is produced when a body creates …………… .

The outer case of the bell in a temple is made big. Give a reason.

How does a man's voice differ from a woman's voice?