Monday, July 27, 2009

What causes lightning and thunder?

This was suggested by a co-worker of mine and since I did tornadoes I thought it could be fun to explore some more interesting weather.

Lightning -

According to the electrostatic induction hypothesis, charges are driven apart resulting in lightning. As strong updraft winds carry water through clouds it super cools the molecules to between -10 degrees celsius and - 20 degrees celsius. As this water collides with ice crystals in the clouds it creates a water-ice micture called graupel. The collisions causea slight positive charge to transfer to the ice crystals and a slight negative charge to transfer to the graupel. Ice crystals are lighter then graupel so the wind blows them to the top of the cloud. This causes the top of the cloud to be positively charged while the bottom is negativeluy charged by the graupel. Charge seperation and accumulation continues until the electical potential is so great that is results in lightning.

Thunder -

Thunder is simply a shock wave caused by lightning. Lightning heats up the air to aproximately 50,000 degrees farenheit. This rapid heating causes the air to expand at speeds faster then the sound can travel through surrounding cooler air, resulting in a shockwave not unlike those caused by explosions.

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