One of the most spectacular natural phenomena is thunderstorms, especially when they produce electrical discharges and deafening sounds. Since ancient times, their presence has been linked to the wrath of the gods. The first thing we see in a storm, especially if it occurs at night, is the flash of lightning, followed by the thunder, and sometimes the subsequent rumblings of other sounds. The difference in time between the flash of light and the thunder is often striking; this is because the speed of light is much faster than the speed of sound: 300,000 kilometers per second versus one-third of a kilometer per second. With the help of a calculator, and after a simple calculation, we can deduce that, if six seconds pass between the flash of lightning and the sound of thunder, the lightning struck approximately two kilometers away. Expansion and contraction of air On a clear day, the Earth's surface is negatively charged, while positive ions predominate in the upper troposphere. As a cumulonimbus cloud develops, the normal charge distribution disappears: at the top and near the cloud, the charges are positive, with a region of negative charges between them. Little by little, positive charges begin to establish themselves on the surface, below the cloud, and it is this difference in charge that results in the famous lightning strike. The electric current heats the surrounding air to around 20,000°C, a temperature that causes it to expand at an enormous speed. When it mixes with the surrounding cold air, the temperature drops sharply, and it contracts. It is precisely this rapid expansion and contraction that results in the appearance of a sound wave that travels in all directions: thunder. In other words, thunder is produced by the sudden heating caused by lightning in the surrounding air, which is, in turn, the result of a struggle between elemental electrically charged forces. Lightning doesn't travel in a straight line. Lightning is perceived as a single phenomenon—a flash of light—while thunder sometimes sounds like a prolonged rumble. The explanation for this phenomenon is that sound deflects in many directions as it travels through the air, creating a series of explosions and shock waves, and because the waves bounce off different objects (trees, buildings, etc.). We can therefore deduce that the further away the sound is from us, the more time it has to bounce off other objects, and therefore, the higher the possibility of what we perceive as a thunderous sound. Furthermore, we must keep in mind that under normal conditions, air does not conduct electricity, and although we imagine it as a homogeneous and orderly mixture of gases, it is very heterogeneous, with varying humidity levels, pressures, temperatures, and currents. MORE INFORMATION news No Why is cheese colored if milk is white? news No Why does beer foam but milk doesn't? All of these variables decisively influence the path a lightning bolt travels; it will always seek the easiest route, even if it has to travel a longer distance. In plain English, lightning bolts don't travel in a straight line.
