It's common knowledge that on summer afternoons, the chirping of crickets is loud enough to catch our attention. But what many people don't realize is that the song of these insects has characteristics that depend entirely on environmental conditions. So much so, that you can determine the ambient temperature quite accurately just by listening to a cricket. Think that's not possible? Keep reading and find out!
Surely it has happened to you that during some oppressive and hot summer afternoon you couldn't take a nap because the insistent chirping of crickets prevented you. It's quite hard to avoid hearing the 'cric cric' with which these little creatures try to attract females (only males sing). To produce that peculiar sound, these insects—cousins of grasshoppers—slightly lift their wings and rub them together. This 'song' has several peculiarities. One of them is that it's quite complicated to know where that annoying sound comes from. This is because the wavelength of the 'cric cric' is almost equal to the distance between our ears, which makes it so difficult to locate a cricket.
But there's another interesting issue associated with the sound crickets emit: the metabolism of these insects is very sensitive to temperature changes, because they are simple beings unable to regulate their own body temperature (something we mammals can do). Their bodily functions and muscle movements occur at different speeds depending on the ambient temperature. There's nothing strange about this: after all, all living beings 'function' through different and complex chemical reactions, and the speed at which they develop depends on the heat supplied, which acts as a positive catalyst.
Swiss chemist and physicist Svante August Arrhenius, who lived between 1859 and 1927, was able—in 1889—to establish a mathematical relationship between the speed of a chemical reaction and the temperature at which it occurs. Simply put, the higher the temperature, the faster the reaction; and vice versa: the lower the temperature, the slower the reaction.
As we said, the metabolism of crickets is nothing more than a succession of chemical reactions, and therefore sensitive to temperature changes. When the surrounding temperature is high, as happens in summer, the chirping of crickets increases in frequency. This is nothing other than the confirmation of the equation found 110 years ago by Arrhenius.
By listening attentively to the chirping of crickets, scientists have determined the mathematical expression that relates temperature to the frequency of these animals' chirps, and the fact is that it is accurate enough to know the ambient temperature with the same precision as a mercury thermometer. In degrees Celsius, the formula in question is the following:
Obviously, the main difficulty when using one of these critters as a thermometer is counting with sufficient precision the number of chirps it emits in a minute. Some recommend doing the count over a 10-second interval and then multiplying the result by 6. There's no doubt this system is faster and more comfortable, but it introduces a larger margin of error. Perhaps the best way is to count the chirps over a longer period (say 10 minutes) and then divide by a larger number (for example, 50). This may be more 'uncomfortable', but it minimizes the measurement error.
Be that as it may, nobody is going to replace a mercury thermometer with a box containing a cricket, but the truth is that it's a good trick with which we can amaze our friends while listening to one of these insects sing. Don't you think?
https://old.neoteo.com/como-se-realizaban-los-primeros-pronosticos-del/
