Materials - flexible plastic ruler Procedure 1. Lay the ruler on a table with half of its length extending past the edge of the table. With one hand, hold the end of the ruler securely to the table. With the other hand, push the free end of the ruler down and then release it. Note any motion of the ruler and any sound produced.
Sound waves are the result of mechanical vibration.
All sounds originate from a vibrating object. As the length of the ruler increases, the frequency decreases. The movement of the air around the vibrating ruler transfers the sound energy through the air so that vibrating air enters your ear and hits against your eardrum, causing it to vibrate. In the inner ear, these vibrations are changed into electrical signals and sent to the brain. The frequency of the vibration of the eardrum is interpreted by your brain as a specific sound.