Home Preparation for National Talent Search Examination (NTSE)/ Olympiad
Chapter : 5. Sound
Working of human ear
(b) Working of human ear : Sound waves from outside are collected by the outer ear (called pinna) and reach the eardrum through the auditory canal. When the sound waves strike the eardrum, (tympanic membrane) it starts vibrating. These vibrations are passed on to the oval window by three bones (called the hammer, anvil and stirrup) which act as a lever with the pivot at point P. They magnify the force of the vibrations. The oval window has a smaller area than the eardrum. So, this increase pressure on the oval window and on the liquid in the cochlea. The vibrations of the liquid in the cochlea affect thousands of auditory nerves which send message to the brain. Our ears are very delicate and fragile organs. Proper care must be taken to keep them in healthy state. Some suggestions to keep the ears healthy are given below : Never insert any pointed object into the ear. It can damage the eardrum and make a person deaf. Never shout loudly into someone's ear. Never hit anyone hard on his / her ear.