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QUESTION Wagner J. dos Santos, Campo Grande, MS
Because of the curvature of the Earth, our eye is able to see, at most, up to 5 km away. But this, of course, depends on several factors, such as eye health, luminosity, visual obstacles, etc. The limit for seeing accurately is much smaller: to read words up to 0.5 cm, the maximum distance is 20 m, for example. The world’s most powerful binoculars can increase your viewing power 160 times. But it costs a “measly” US$ 400.
+ Which animal has the best eyesight?
+ How many megapixels does the human eye have?
Hearing almost does not depend on distance, but on other characteristics of sound. After all, you can hear thunder from miles away, but not a pin drop in the next room. Some of the influential aspects are intensity, sound pressure, and, mainly, frequency, measured in hertz (Hz). We managed to capture between 20 Hz (like the lowest notes on a tuba or a pipe organ) and 20,000 Hz (everyday sounds usually reach up to 8,000, like a motorcycle).
CONSULTANCY Mauro Campos, ophthalmologist, and Cláudia Esteves Dias, otorhinolaryngologist