you need
  • stopwatch, calculator
So, expect the zipper with a stopwatch in hand.At the time of the outbreak, start the stopwatch when you hear thunder, turn off the stopwatch.The result is a delay time of thunder - that is, the time during which the air swings passed from place to discharge you.
Further, the distance from the known formula, is the product of speed for a while.The time you have.As for the speed of sound in the atmosphere, for the calculation of gross enough to remember the value of 343 meters per second.If you want to calculate the distance more or less accurately, it should be remembered that in the humid air sound travels faster than in the dry, hot and more - faster than in cold.For example, a cold autumn rain
shower at the speed of sound in air is 338 m / s, and hot and dry summers - 350 m / s.
now consider.For example, from lightning to the sound of thunder it took 8 seconds.
Take the speed of sound - 343 m / s, then the distance to the lightning is 8 * 343 = 2744 meters, or (rounded) 2.7 kilometers.If the temperature of 15 degrees Celsius at 80% humidity (rain average power), the speed of sound will be 341.2 m / s and 2729.6 m distance (may be rounded to 2.73 km).
You can enter the tolerance for the direction of the wind.If the wind is blowing toward you from lightning, the sound will be held this distance is somewhat faster, and at the direction of the wind from you to lightning - a little slower.For rough calculations enough to remember that in the first case (the wind to lightning), the distance must be reduced by 5%, while in the second (wind from lightning) increased by 5%.Thus, in case of delay of thunder 8 seconds and the speed of sound 343 m / sec at the direction of the wind from lightning to you distance 2744 meters should be increased to 137.2 m.