HEARING

PURPOSE : To demonstrate how sound is heard.

MATERIALS :

                               Metal spoon

                               2 feet (61 cm) of kite string
                               Ruler

PROCEDURE :

• Tie the handle of the spoon in the center of the string.
• Wrap the ends of the string around both index fingers. Be sure that both strings are the same length.
• Place the tip of an index finger in each ear.
• Lean over so that side of a table.

RESULTS : It sounds like a church bell.

WHY ? The metal in the spoon start to vibrate when struck. These vibrations are transmitted up the string to the ears. The ability to hear is due to one’s ability to detect vibration. Objects must vibrate to produce a sound. The vibrating object causes the air around it to move. Vibrating air molecules enter the air and strike the air drum causing it to vibrate. These vibrations continue to travel through bones and fluids in the ear until they reach a nerve that sends the message to the brain.