The Science of Thunder and Lightning

Astrapophobiabrontophobia, keraunophobia, ortonitrophobia, or nicaduranaphobia, is an abnormal fear of thunder and lightning, a type of specific phobia. It is a treatable phobia that both humans and animals can develop.night-thunder-storm-lightningphoto by https://www.healthtopia.net/disease/mental-health/phobia/astraphobia-causes-symptoms-treatment

How does a Thunder and Lighting forms? Where do they come from. In this blog I will show you the Science behind Thunder and Lightning.

 

THUNDER

Thunder is the audible pressure (compression) wave produced by lightning. Nearly all lightning is generated by thunderstorms. However,lightning has also been observed during snowstorms, in columns of billowing smoke from forest fires, in erupting volcanic debris clouds, near fireballs created by nuclear explosions, and on some planets and moons in our solar system. Lightning is a giant static electrical spark. Where there’s lightning, there’s thunder, and vice versa. It is also the sound generated from the Lightning produced by a sudden and violent expansion of super-heated air in and along the electrical discharge channel path. Thunder can be a sharp or rumbling sound. The intensity and type of sound depends upon atmospheric conditions and distance between lightning and the listener. The closer the lightning, the louder the thunder.thunder-953118_960_720.jpgphoto by Pixabay.com

Science of Thunder

Less than 1% of lightning’s energy is converted into sound and the rest released in the form of light. The shock wave extends outward for the first 30 feet (10 m), after which it becomes an ordinary sound wave called thunder. Thunder can cause property damage when you are in close range

Thunder is seldom heard beyond 10 miles (16 km) under ideal conditions. The sound of distant thunder has a characteristic low-pitched rumbling sound. Pitch, the degree of highness or lowness of a sound, is due to strong absorption and scattering of high-frequency components of the original sound waves, while the rumbling results from the fact that sound waves are emitted from different locations along the lightning channel, which lie at varying distances from a person. The longer the lightning channels, the longer the sound of thunder. Humans hear frequencies of thunder between 20-120 Hertz (Hz). However, there is a small amount, less than 10%, that is inaudible to humans produced from lightning, called infrasonic. Special listening devices are required to record these inaudible sounds.

The sound that you can hear during a Thunder is made up of vibrations. It travels as a sound wave through the air, until it reach your ear. The crack sound is the direct sound of the lightning that traveled through our ears. Thunder contains different shock waves, each shock wave takes a different amount of time to reach your ear.

Wow, so that’s how Thunder is formed! Amazing, Everytime a hear a Thunder I was always curious about the science behind it. Now that we know the Science behind Thunder let us proceed on the Science behind Lightning.

download.jpgphoto by combiboilersleed.com

LIGHTNING

During any given minute, there are more than a thousand thunderstorms around the Earth causing some 6,000 flashes of lightning. Every minute!

Lightning is a huge discharge of electricity, and this electricity shoots through the air, causing vibrations to be formed in two ways:

  1. The electricity passes through the air and causes air particles to vibrate. The vibrations are heard as sound.
  2. The lightning is also very hot and heats up the air around it. Hot air expands, and in this case the air expands very quickly, pushing apart the air particles with force and creating more vibrations.

How lightning strikes

When the negative charge in the cloud becomes great enough, it seeks an easy path to the positively charged ground below. The current looks for a good conductor of electricity, or a tall structure anchored to the ground (such as a tree or a tall building). The negative charge sends out a feeler, called a stepped leader, which is a series of invisible steps of negative charges.

As the stepped leader nears the ground, a positive streamer reaches up for it. Only then, once this channel is made, does the visible lightning happen. A return stroke runs from the ground to the clouds in a spectacular flash.

Though the bolt appears continuous, it is actually a series of short bursts. Most lightning strikes occur in less than a half second and the bolt is usually less than 2 inches in diameter.

Lightning begins as static charges in a rain cloud. Winds inside the cloud are very turbulent. Water droplets in the bottom part of the cloud are caught in the updrafts and lifted to great heights where the much colder atmosphere freezes them. Meanwhile, downdrafts in the cloud push ice and hail down from the top of the cloud. Where the ice going down meets the water coming up, electrons are stripped off.

It’s a little more complicated than that, but what results is a cloud with a negatively charged bottom and a positively charged top. These electrical fields become incredibly strong, with the atmosphere acting as an insulator between them in the cloud.

Lightning is an important part of weather forecasting. The new GOES-R Geostationary Lightning Mapper instrument will detect lightning activity over nearly the whole Western Hemisphere. This complete picture of lightning at any given time will improve “now-casting” of dangerous thunderstorms, tornadoes, hail, and flash floods.

Here are some facts about Thunder and Lightning!

Why is thunder not at the same time as the lightning?

We see the lightning before we hear the thunder because light travels faster than sound. The light from the lightning travels to our eyes much quicker than the sound from the lightning. so we hear it later than we see it. There is an old myth that counting seconds between a lightning flash and the accompanying thunder gives you the distance of how far away the storm is, in miles. However, from a mathematical point of view we know this isn’t true, as the speed of sound is roughly 330 metres per second. So it takes roughly 3 seconds for the thunder to travel one kilometre, and therefore about 5 seconds for thunder to travel a mile. So, a more scientific rule would be, count the number of seconds between the lightning flash and the thunder noise, and then divide that number by five, and that is how many miles away the thunderstorm is.

Extreme sounds like this are incredibly fascinating, especially to scientists like us who investigate how such things happen. Extreme sounds don’t just have to be loud, they can also be powerful enough to shatter a wine glass, or can even be used as a weapon in the animal kingdom. We’ve spent so much time finding out new ways that sound shapes and transforms our lives, that here at science made simple we even wrote a whole science show about extreme sounds, so we can tell as many people about them as we can.

What causes the sound of Thunder?

Thunder is caused by the rapid expansion of the air surrounding the path of a lightning bolt.

Source: ©National Lightning Safety Institute ~ January 5 2017

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