How Sensitive Are You?

If your senses are working normally, you can: Feel on your fingertips or face a pressure that depresses your skin a bare .00004 inch. See a small candle flame from 30 miles away on a clear, dark night. Smell one drop of perfume diffused through a three-room apartment. Taste .04 ounce of table salt dissolved in 530 quarts of water. Feel the weight of a bee's wing falling on your cheek from less than half an inch away. Distinguish among more than 300,000 different color variations. Gauge the direction of a sound's origin based on a .00003-second difference in its arrival from one ear to the other.