Ion Watson, age 12, of Calgary, Alberta, Canada, for his question:

Is it true the inner ear helps us to balance?

The inner ear is small enough to sit comfortably on the lower shelf of your outer ear. It is buried safely inside the bony skull. Nature is a genius at designing important items to fit into small spaces. The complex and delicate inner ear contains sense organs of both hearing and balancing.

A first grader knows that his ears are for hearing and he tends to think that the hearing is done by those two graceful shells of gristle, one on each side of his head. Liter, he learns that these outer ears merely trap surrounding sounds and guide them inside his head. The real hearing job is done by the inner ear, a complicated little gadget somewhat like a group of weird instruments for a one band. It has an intricate maze of winding tunnels and twisting tubes, drums and hammers, walls that are sounding boards and an echo chamber coiled like a conch seashell.

The weird little instruments are delicately inter related. They are connected to nerve threads that meet and merge to carry information and impulses to the brain. Most the parts relay sound data to the special hearing headquarters centered in the cerebrum of the brain. There, the countless subtle sounds are interpreted to reveal the loudness and . pitch, the tone and timbre, the distance and numerous other qualities of a noise. But one odd shaped part of the inner ear is not a part of the one band.

This small system of coiled canals is not even a sound instrument and its nerve threads do not join the telephone line to the brain's hearing center.

This silent member is the organ of balance. Its countless fine nerves send a constant stream of directional information to the brain. This data travels to the cerebellum brain section tucked low in the back of the skull. The cerebellum contains the body's balancing' center of equilibrium. It receives and sorts data from the inner ear and flashes orders to teams of ever ready muscles. It can correct a possible tumble faster than you can think.

The balancing organ in the inner ear is a triplet of looped tubes called the semicircular canals. Each canal is partly filled with fluid and the fluid level tips and tilts with the motions of the head. One canal is horizontal and two are vertical. The trio is cleverly placed to catch news from all directions. Their inside walls have patches of inner ear hairs with sensitive cells. These hair cells are attached to nerve fibers that pass through the walls and merge to form a trunk line called the vestibular nerve. As the head moves, the fluid levels tip like water in a tilted glass. The changing levels touch and trigger sets of hair cells. Details of these up and down tips and tilts are flashed faster than sound to the balancing center in the brain. Based on these news items, muscles are ordered to balance and rebalance the body's weight in line with the earth's gravity.

Sometimes the fluids of the semicircular canals fail to stop moving on schedule. If you spin around and around, the little puddles continue to swirl after you stop. They send a jumble of inaccurate data to the brain. The balancing center becomes confused and you feel as though you are still spinning dizzily around. The heaving motion of a ship also may upset the fluids of the inner ear and the wobbly sensation of vertigo may cause seasick