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By Nancy Steinbach
Broadcast: July 2, 2003
This is Steve Ember with the VOA Special English Health Report.
Lightning is the release of electrical energy in the sky. Lightning can start fires. It also can kill.
During a storm, the normally 1)neutral particles in clouds hit each other. They become electrically charged. As they flow toward each other, they form an electric 2)spark of light.
Some lightning is created between clouds. Other lightning is created within clouds. And some is created when 3)negative charges from a cloud's base move down to meet positive charges rising from Earth.
Lightning that strikes the Earth carries one or more electrical discharges called strokes. The bright light seen in a flash of lightning is called a return stroke. Return strokes travel at the speed of light. They discharge about one-hundred-million 4)volts of electricity. They heat the air to more than thirty-three-thousand degrees Celsius. Air heated by return strokes expands and produces the sound of 5)thunder.
About four-hundred people are struck by lightning each year in the United States alone. About one-hundred die. The electrical force of the lighting affects the heartbeat. Lightning can also stop the chest muscles or damage the breathing center in the brain.
Experts tell people to seek the safety of a building or a hard-top vehicle any time they hear thunder, even if it is not raining. They say lightning can strike as far as sixteen kilometers away from any rainfall. Lightning can also travel sideways for up to the same distance. At least ten percent of lightning happens without clouds in the sky.
Safety experts also say that people in a building should stay away from anything with wires or pipes that lead to the outside. The National Weather Service says if you plan to disconnect any electronic equipment, do so before the storm arrives. Do not use a wired telephone. Do not use water. All these can carry electricity.
People who are outside should make sure there are not the tallest things around. Bend low to the ground, but do not lie down. Do not stand near a tree or any tall object. Stay out of -- and away from -- water. Get away from bicycles and other things made of metal. A car is safe, but do not touch any metal inside.
Experts also say that a person who has been struck by lightning carries no electrical charge afterward. It is safe to begin emergency treatment.
This VOA Special English Health Report was written by Nancy Steinbach. This is Steve Ember.
注释：
1) neutral [5nju:trEl] adj.无确定性质的，(颜色等)不确定的
2) spark [spB:k] n.火花，火星，闪光
3) negative [5ne^Etiv] adj.负的，阴性的
4) volt [vEult] n.（电工）伏特
5) thunder [5WQndE] n.雷，雷声 |