Here is wat u need..hope this helps
Jaltarang is based on the principle the pitch of sound depends upon its frequency
u can make it at ur home too
here are the steps
take a few china soup bowls and fill them with water to different levels. now strike the edge of each bowl with a pencil (or any similar wooden stick). u will note the difference in the nature of sounds produced by these bowls.the bowl containing the maximum amount of water produces a high pitch ( high frequency ) sound. the bowl containing least amount of water produces a low pitch ( low frequency ) sound.