Thunder is the sound lightning that permeates the air. When the first lightning arrow tends to land, it carries an electrical charge. Meet her from the ground pulled the spark charge. Connection to the cloud begins to rise the current, gaining strength up to 20,000 amps. And the temperature of the channel through which it is current, can be above 250000 C. such a high temperature the molecules of air scatter, and he is expanding with supersonic speed and forms a shock wave. A deafening roar caused by these waves, called thunderohms. Due to the fact that the speed of light is much higher than the speed of sound, lightning is seen at once, and thunder is heard much later.Peals of thunderand occur due to the fact that the sound comes from different parts of lightning, having a considerable length. In addition, the discharge itself does not occur in an instant, but lasts a certain time. The sound produced may be affected by echoes from surrounding objects: mountains, buildings and clouds. So people hear not one sound, and some catching up with each other echoes, the thunder ofthe bone which can exceed 100 decibels.To roughly calculate at what distance the lightning struck, it should be noted the number of seconds that pass between a flash and a strike of thunder. And then divide the resulting figure by three. Comparing these calculations, it is also possible to make a conclusion about whether the approaching storm, or Vice versa, is deleted. Usually a thundertype thunder can be heard at a distance of 15 to 20 kilometers from the lightning flash.