Science Projects Index

Sound Pitch

If you observe carefully, you can recognise a person by seeing his eyes. Cut out two cardboards in the shape of an L. Now you should cut the pictures of many famous persons from a magazine. Show these pictures to your friends. Now place the L cards on the pictures one by one, so that only the eyes are visible. Ask your friends to now identify the persons.

Recognising By Seeing the Eyes

Take a 33 RPM record player and place it on the turntable. Now, instead of playing it at the correct speed of 33 RPMs, turn it at a speed of 45 RPMs. The voice that comes out will be shrill and different. This is because of the higher speed of the turning, the frequency of the sound will also increase, causing a higher pitch which makes the sound shrill.