Why does thunder accompanies lightning

Cloud-to-ground lightning, where lightning strikes the ground, is just one possible result of the charge imbalance in storm clouds. Lightning can also jump between the differently charged regions in clouds without reaching down to the ground at all, or even between separate clouds.

As well as being fast, lightning can heat the surrounding air to an incredibly high temperature. The heating of nearby air causes it to expand rapidly ; it then cools and contracts. This creates the sonic shock wave we refer to as thunder. Because the sound of thunder travels at a much slower speed than the flash of lightning, you can use it to estimate the distance you are from a lightning strike. Sound travels at approximately metres per second in air, so the sound of thunder travels about 1 kilometre in 3 seconds.

If you can see the lightning, you can work out how far away the storm is! The oddly sweet, pungent smell that sometimes precedes a storm is that of ozone. Lightning strikes split diatomic oxygen molecules in the atmosphere into individual oxygen atoms. These can then combine with other oxygen molecules to form ozone.

Thunderstorms always have lightning thunder is caused by lightning, and you can't have a thunderstorm without thunder! What causes thunder? Thunder is caused by lightning. The bright light of the lightning flash caused by the return stroke mentioned above represents a great deal of energy.

The air that is now heated to such a high temperature had no time to expand, so it is now at a very high pressure. The high pressure air then expands outward into the surrounding air compressing it and causing a disturbance that propagates in all directions away from the stroke.

The disturbance is a shock wave for the first 10 yards, after which it becomes an ordinary sound wave, or thunder. Fun fact: thunder can seem like it goes on and on because each point along the channel produces a shock wave and sound wave, so what you hear as thunder is actually an accumulation of multiple sound waves from the different portions of the lightning channel.

Thunder starts at the same time, but its sound travels one million times more slowly, about metres per second. The distance can be estimated by counting the time interval between the lightning flash and the start of the thunder. If you count seconds and divide them by three, you get the distance in kilometres. Thunder is rarely heard at a distance of more than 20 km.

Thunder cannot hurt anybody except by the sound-pressure shock if the lightning hits very close , and the risk of being struck by lightning is far less than that of being killed in a car crash. Most lightning occurs as cloud flashes, which are harmless on the ground.

Most of the flashes that do strike the ground cause little or no damage or harm. Lightning often chooses a well-exposed target on the ground, usually a high well-conducting object standing alone. Lightning strikes lone trees on high ground, so a wise thing would be to not seek a shelter under a tree. If you are in the open and find no shelter, make yourself low by crouching down, keeping the feet together.

Indirect dangers from thunderstorms are lightning-ignited fires, overvoltages in electric and telecommunication lines, and gusts of strong wind. Lightning strikes aircraft, but the people inside are safe because it runs around the outside. Lightning strikes tall buildings, but they have lightning conductors to carry the electricity harmlessly to the ground. The safest place might be in a car. Skip to main content.

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