Definition of Thunder
Thunder signifies the auditory phenomenon resulting from the abrupt air expansion due to extreme heating triggered by a lightning discharge. A lightning bolt's journey through the atmosphere induces significant heating of adjacent air, prompting the air to expand swiftly and spawn a shock wave. This shock wave propagates through the atmosphere, yielding the audible sensation recognized as thunder.
Relation Between Lightning and Thunder
An indissoluble bond exists between lightning and thunder, with thunder manifesting as a consequence of a lightning discharge. Lightning materializes when an electric discharge in a thunderstorm bridges the electric potential disparity between the ground and the storm cloud. The thermal energy discharged by lightning consequently heats the ambient air, thereby initiating thunder's formation.
Types of Thunder
Thunder displays several forms, contingent on the sound's attributes and the lightning strike's proximity. Claps correspond to abrupt, resonant sounds indicative of a nearby lightning strike. Peals denote sounds undergoing pitch and volume alterations, typically resulting from multiple lightning discharges or reverberations from close structures. Rolls are extended, rumbling sounds stemming from remote lightning strikes or thunder sound traversing diverse atmospheric layers.
Thunder and the Speed of Sound
Atmospheric speed of sound plays a pivotal role in thunder's perception. Sound travels approximately 1,125 feet (343 meters) per second in dry air at 68°F (20°C). This finite speed entails a delay between the visual lightning flash and the audible thunder, with the light reaching the observer ahead of the sound. To crudely estimate a lightning strike's distance, one may count the seconds separating the flash and the thunder, then divide by five for the distance in miles (or by three for the distance in kilometers).
Thunderstorms and Safety Precautions
Thunderstorms are capable of generating extreme weather conditions, incorporating potent winds, hail, torrential rain, and lightning. Consequently, safety measures become essential upon hearing thunder. The 30-30 rule is a valuable directive for determining outdoor safety during a thunderstorm. After witnessing a lightning flash, the observer should count the seconds until hearing thunder. If this duration is under 30 seconds, immediate shelter is advised. Indoor stay should extend for a minimum of 30 minutes following the final audible thunder to guarantee the storm's passage.
Thunder in Folklore and Culture
Historically, thunder has served as a source of wonder and trepidation, often attributed to divine or supernatural entities' actions. Numerous cultures harbor myths and legends concerning thunder, typically featuring deities employing thunder and lightning as weaponry or tools to enforce their will. Presently, thunder continues to evoke awe and admiration, symbolizing nature's formidable power.