NATURE HAD IT FIRST

NATURE HAD IT FIRST In 1973, Dr Martin Copper was the first to demonstrate a hand-held cellular telephone. It had a battery, a radio and a micro-processor [a minicomputer]. New Yorkers gaped in amazement when they saw cooper making a phone cell on the street. But the invention was possible only because back in 1800 Alessandro Volta had invented a reliable battery. In addition, the telephone had been developed by 1876, the radio by 1895, and the computer 1946. Finally, the invention of the microprocessor in 1971 made cell phones possible. Nevertheless, we might ask, was communication with sophisticated devices really new? A communication device often taken for granted is the human voice. Over half the billion of neurons in the motor cortex of your brain are involved in controlling your speech organs, and about 100 muscles operate the complex mechanism of your tongue, lips, jaw, throat, and chest. Although some animals can hear sound frequencies beyond the range of human hearing, the combination of a human’s ears and brain is a formidable one, say audio experts. Our hearing enables us to determine loudness, pitch, and tone and to approximate the direction and distance of a sound source. The frequency range of a healthy human ear is roughly 20 to 20,000 hertz, or cycles of sound oscillation per second. The most sensitive region is in the 1,000 to 5,000 hertz range. Moreover, we may be able to detect a change of just one hertz from, say, 440 hertz to 441 hertz. Indeed, a healthy ear is so sensitive that it can detect sounds when the vibration, or to-and-fro movement, of the air at the eardrum is less than the diameter of an atom! According to a university course on hearing, “the human hearing system is close to the theoretical physical limits of sensitivity… There would be little point in being much more sensitive to sound, as all would hear would be a ‘hiss,’” the result of the random movement of the atoms and molecules that make up the air. Eardrum vibrations are amplified mechanically by lever action and are transferred to the inner ear by means of the OSSICLES –tiny bones known as the hammer, the anvil, and the stapes. But what if your ears are suddenly struck by a deafening sound? In that event, they have built-in protective mechanism in the form of muscle action that adjusts the OSSICLES to reduce the force of the sound. However, the ears are not equipped to deal with prolonged loud noise. Such exposure can permanently damage the hearing. Your auditory system also helps you to detect a sound source. The secret lies in a number of factors, including the shell-like shape of the outer ears, its grooves, the separation of the two ears, and some computational brilliance on the part of your brain. Thus, if the intensity of a sound fades just slightly from ear to ear or if the sound reaches one ear just 30 millionths of a second before it reaches the other, your brain will promptly point your eyes toward the sound source.