The cause of thunder

Go down

The cause of thunder

Post  taixyz1992 on Fri Dec 31, 2010 6:51 am

The cause of thunder has been the subject of centuries of speculation and scientific inquiry. The first recorded theory is attributed to the Greek philosopher Aristotle in the third century BC, and an early speculation was that it was caused by the collision of clouds. Subsequently, numerous other theories have been proposed. By the mid-19th century, the accepted theory was that lightning produced a vacuum. In the 20th century a consensus evolved that thunder must begin with a shock wave in the air due to the sudden thermal expansion of the plasma in the lightning channel. The temperature inside the lightning channel, measured by spectral analysis, varies during its 50 μs existence, rising sharply from an initial temperature of about 20,000 K to about 30,000 K, then dropping away gradually to about 10,000 K. The average is about 20,400 K (20,100 C; 36,300 F).[1] This heating causes it to expand outward, plowing into the surrounding cooler air at a speed faster than sound would travel in that cooler air. The outward-moving pulse that results is a shock wave,[2] similar in principle to the shock wave formed by an explosion, or at the front of a supersonic aircraft. More recently, the consensus around the cause of the shock wave has been eroded by the observation that measured overpressures in simulated lightning are greater than what could be achieved by the amount of heating found. Alternative proposals rely on electrodynamic effects of the massive current acting on the plasma in the bolt of lightning


Semi Permanent Eyebrows
Medical Marijuana Dispensaries

taixyz1992
steve harmisson

Posts : 186
Join date : 2010-09-17

View user profile

Back to top Go down

Re: The cause of thunder

Post  heroisthai on Tue Jan 04, 2011 4:36 am

This heating causes it to expand outward, plowing into the surrounding cooler air at a speed faster than sound would travel in that cooler air. The outward-moving pulse that results is a shock wave,[2] similar in principle to the shock wave formed by an explosion, or at the front of a supersonic aircraft. More recently, the consensus around the cause of the shock wave has been eroded by the observation that measured overpressures in simulated lightning are greater than what could be achieved by the amount of heating found.







______________________
Artesanias infantiles
trucks

heroisthai
steve harmisson

Posts : 138
Join date : 2010-11-21

View user profile

Back to top Go down

Re: The cause of thunder

Post  tranthuongbn on Wed Jan 05, 2011 4:04 pm

It is known as the Sindhu Sagar to Indians since the Vedic period of their history, and an important marine trade route in the era of the coastal sailing vessels from possibly as early as the 3rd millennium BCE, certainly the late 2nd millennium BCE through the later days known as the Age of Sail. By the time of Julius Caesar, several well-established combined land-sea trade routes depended upon water transport through the Sea around the rough inland terrain features to its north.

microphone hire melbourne
health insurance alabama

tranthuongbn
leg end

Posts : 18
Join date : 2010-12-25

View user profile

Back to top Go down

Re: The cause of thunder

Post  heroisthai on Thu Jan 13, 2011 7:48 pm

The cause of thunder has been the subject of centuries of speculation and scientific inquiry. The first recorded theory is attributed to the Greek philosopher Aristotle in the third century BC, and an early speculation was that it was caused by the collision of clouds. Subsequently, numerous other theories have been proposed. By the mid-19th century, the accepted theory was that lightning produced a vacuum. In the 20th century a consensus evolved that thunder must begin with a shock wave in the air due to the sudden thermal expansion of the plasma in the lightning channel. The temperature inside the lightning channel, measured by spectral analysis, varies during its 50 μs existence, rising sharply from an initial temperature of about 20,000 K to about 30,000 K, then dropping away gradually to about 10,000 K. The average is about 20,400 K (20,100 C; 36,300 F).[1] This heating causes it to expand outward, plowing into the surrounding cooler air at a speed faster than sound would travel in that cooler air. The outward-moving pulse that results is a shock wave,[2] similar in principle to the shock wave formed by an explosion, or at the front of a supersonic aircraft. More recently, the consensus around the cause of the shock wave has been eroded by the observation that measured overpressures in simulated lightning are greater than what could be achieved by the amount of heating found. Alternative proposals rely on electrodynamic effects of the massive current acting on the plasma in the bolt of lightning





Who Needs A Cpap Machine
chess sets

heroisthai
steve harmisson

Posts : 138
Join date : 2010-11-21

View user profile

Back to top Go down

Re: The cause of thunder

Post  Sponsored content


Sponsored content


Back to top Go down

Back to top

- Similar topics

 
Permissions in this forum:
You cannot reply to topics in this forum