Science Questions

As lightning comes down from a cloud, does a positive charge go up to meet it? Is this what throws people up into the air? Mike, Beatley.

Like charges repel and opposite charges attract. So when there’s a concentration of negative charge in a cloud, such as just before a lightning strike, negative charges in the ground are repelled and move away, leaving a positively charged ground. When these charges attract each other enough, the lightning overcomes the natural resistance of the air and discharges as a fine thread of lightning, usually only about 1 cm across.

People are thrown around when struck by lightning because of their own muscles, in a process called opisthotonus – sudden catastrophic muscle contraction. When the electricity runs through the body, all of your muscles contract at once. The strongest muscles in the body are the ones which hold you upright, so you are thrown off the ground.

July 2007