Remember the times when we were little and we used to feel scared of the thunder and lightning when there’s a storm? The booming sound is so loud it sounds like a bomb exploding. This childish impression is somewhat true.
Exploding Air
Thunder is produced when air explodes inside a thundercloud when lightning heats it up. A strike of lightening can immediately heat up the air to between 15,000 and 60,000 degrees Fahrenheit, which is hotter than the Sun’s surface. When the air is heated quickly, it expands violently and then contracts, which causes an explosion of air. Boom! The air rushing out sets up a sound wave of vibrating air, which is what we call as thunder.
Cold and Warm Fronts
Lightening and thunder happen at exactly the same time because lightning is produced by cold and warm masses of air clashing against each other. The friction between them create sparks of electricity that we call lightning, which shoots down to the ground. Aside from lightning, the clash between cold and warm fronts of air produce a booming sound that is thunder.
Why do we see lightning first before we hear thunder?
Both thunder and lightning happen at the same time, but we see lightning first before we hear the thunder. This is because light travels faster than the speed of sound through the atmosphere. The longer the gap between the lightening and thunder the further away the thunderstorm is.
Light travels faster than sound and the sound of thunder takes about three seconds to travel one kilometer. If you count to three just before you hear the thunder, the lightning is about one kilometer away. If the lightning and the thunder happen at the same time then the lightning is surely very, very close.
Why does thunder rumble?
The sound of thunder differ from time to time. It’s often described as a rumble or a roll. Thunder rumbles because of two things: the lightning bolt and the clouds. A lightning bolt can have forks zigzagging all over the place. The limbs can branch out for many miles.
As a result, when the air explodes whenever lightning heats the air, the compression waves created by each part of the lightning bolt will reach you at different times. The sound wave that has traveled a greater distance will be softer and will arrive later than a sound wave that was created by a part of the lightning bolt that was closer to you.
The second factor that makes thunder rumble is the presence of clouds and mountains around the area. The sound wave bounces around and off the clouds, the ground, and other objects nearby much like the way your voice would echo in a canyon or large auditorium. This is why the sound of thunder might get loud, then soften a bit, then get loud again.
There can be lightning without thunder, but not thunder without lightning. The reason may be because the person is too far away to hear the thunder. The sound waves have dissipated, but the lightning is still visible across the sky.