As unbelievable as it seems, this is completely true. You can tell the temperature by listening to how many times they chirp in a given interval. The only problem is that no one quite agrees on which formula yields the best results. One of the oldest and most reliable formulas comes from the Old Farmerís Almanac, but other formulas have been more scientifically developed.
Male crickets have the ability to rub their legs together and make a loud chirping sound. They do this to attract mates. No one knows who the first person was to discover a connection between temperature and the number of chirps a cricket makes, but we do know who the first person was to study the idea.
The first study was conducted in 1897 by physicist Amos Dolbear. He did not set out to discover how to tell the temperature by cricket chirps. He simply wanted to document how many chirps crickets made at different temperatures. Dolbear created the equation for the correlation of chirps by temperature. It is now officially known as Dolbearís Law: T=50+[(N-40)/4] where T is the temperature in Fahrenheit and N is chirps per minute.
Later, several people attempted to simplify the equation so it could more easily be used in the field.
The most popular of the simplified formulas is the one in the Old Farmerís Almanac. In this method, you count the number of chirps a single cricket makes in 14 seconds then add 40. The result is the temperature in Fahrenheit. To get the temperature in Celsius, count the chirps in 25 seconds, divide that number by 3, then add 4.
A program funded by NASA studied this phenomenon and claims to have developed a more accurate formula, which is not too far off from the Farmerís Almanac. This formula is to add the number of chirps in 13 seconds to 40 for the temperature in Fahrenheit.
Another popular formula is to count the chirps in 15 seconds and add 37.
Posted 2824 day ago