It is nearly impossible to enjoy a cloudburst without quaking to a crack of thunder! The violet clouds followed by torrential rain and flashes of lightning are almost imperfect without the ripping roar of a shattering thunder. So what makes thunder the harbinger of tempest and squall? Early civilizations believed thunders to be the handiwork of some angry gods lashing out their wrath by bombing roaring sparks on earth. However, science bids to offer a more logical and scientific explanation for this. When a spark of lightning shoots through the air, it massively amplifies the temperature causing the air molecules to expand. The air molecules cannot retain their heat for long and cool down rapidly, resulting in a large rumble due to clash of extreme temperature in the air. The cause of thunder has been subjected to speculations for centuries now. While Aristotle believed that thunder was caused by the collision of clouds, 19th century fanatics agreed that lightning was produced as a result of sudden thermal expansion of the plasma in the lightning channel. If you have been really wondering on what the exact causes of thunder are, then checking the following article on the causes of thunder will leave you better informed.
Causes Of Thunder
The cause of thunder has always been a matter of great wonder and conjecture to the world. Earlier, people opined that thunder was triggered due to collision of clouds. However, recent researches have negated this speculation and has forwarded a new explanation altogether. The new theory explains that when lightning strikes, there is almost an instant expansion of air, which sends out a sonic shock wave, or a vibration that results in a loud explosion. To cut the long theory short, thunder occurs due to rapid expansion and contraction of air caused by lightning.
Contrary to the given myth, the sonic boom of a thunder is not the effect of a lightning bolt breaking the sound barrier, but rather the upshot of rapid heating and cooling of the air. Thunder is nothing but an audible shock wave triggered by massive friction between conterminous air molecules. The quick expansion and contraction of air molecules generates a blast wave that results in a large crack, sharp boom or even a low rumble.
Thunder is produced along the same length of the lightning channel and often lasts for more than a few seconds. Close lightnings do not make large booms since the shock wave is often overpowered by the thunder sound overhead. The intensity of the thunder often varies according to the magnitude and nature of the lightning. To get an idea of how near or far the lightning is to you, just note the interval between the flash of lightning and the sound of thunder and then divide it by five. If you are close to the lightning then you will hear a large crack. However, if you are far away, you will only hear a clap of thunder or low rumbling.
Thunder that strikes far away from the terrain have a more rumbling sound due to reflection, damping and scattering of the sounds. At times, thunder cannot be heard altogether. If the thunder occurs 15 miles away from the lightning discharge, the sound wave cannot make it to the surface due to the density of atmosphere.