North coast storm. Lightning over the ocean. Photographed from Seven Mile Beach, Lennox Head looking north east. Photo Patrick Gorbunovs / The Northern Star
North coast storm. Lightning over the ocean. Photographed from Seven Mile Beach, Lennox Head looking north east. Photo Patrick Gorbunovs / The Northern Star

Why are thunderbolts and lightning very, very frightening?

We all know "thunderbolt and lightning (is) very, very frightening", thanks Freddie, but what makes thunder so … well thunderous?

Residents across the Northern Rivers experienced "window rattling" thunder during this morning's storm, and wondered why some thunder was louder, and scarier, than others.

We looked to experts to explain it.

This cool video by National Geographic on YouTube explains the science behind storms, lightning and thunder.

Basically, positive and negative build up in a storm cloud, eventually forming electricity that results in the lightning strike.

This happens so quickly, the air around the lightning expands rapidly, causing a shockwave in the air.

A spokeswoman from the Bureau of Meteorology said thunder, "is a shockwave for about the first 10m then becomes an ordinary sound wave as it dissipates through the air".

She said many elements can affect how loud the thunder sounds.

She said during a thunderstorm, there is often a lot of reflection of sound.

Thunder can bounce around between clouds and the ground, making it sound much louder and carrying the sound for longer, then if it were to dissipate in the air in an open field.

Other elements also impact the sound.

Humidity - thunder is louder with higher humidity as moist air absorbs less energy as it is less dense than dry air.

Wind - it distorts sound, think of an outdoor stadium

Temperature - sound passes through hot air faster than cold air because it is less dense.

Terrain and clouds - sound waves bounce off these.

Lightning can also be very loud when it hits something.

The BoM spokeswoman said the rattling of windows people were experiencing was probably caused by the ground shock of lightning hitting the ground, or an object, rather than the shockwave.

Also, light travels faster than sound, so the old wives tale, where the seconds between seeing the lightning and hearing the thunder equates to how far away it struck land, has truth.

Interesting fact: The scientific study of thunder is called brontology.



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