Typical smell Why does it smell like rain in summer?
After heat and drought, now thunderstorms. It smells so pleasantly of rain. Why is that? And why is it life-threatening when lightning strikes nearby? Some answers.
Temperatures of around 30,000 degrees and a sound pressure of up to 130 decibels: summer thunderstorms are an impressive force of nature. But that's precisely why you should only watch them from a distance.
Why does it smell like rain?
Researchers call the typical smell when it rains again after a long dry spell "petrichor". Two Australians, who derived the term in 1964 from the ancient Greek words "petros" (stone) and "ichor" (mythologically the liquid in the veins of the gods), found out in simple terms: the odorless water whirls up dust particles that carry, among other things, the aroma of an oil that plants produce during drought.
How exactly does the scent reach the nose?
Researchers at the Massachusetts Institute of Technology described this in more detail in 2015: A raindrop traps tiny air bubbles beneath it on the ground. These absorb the smell of the dusty ground, then bubble upwards like carbon dioxide in sparkling water and splash out of the drop's surface into the air.
Wind disperses the scents. This is one of the reasons why some people can smell rain before it even falls where they are standing. The researchers found that the smell is more intense in lighter rainfall than in heavy rain.
How do lightning and thunderstorms occur?
Thunderstorms occur when warm, moist air masses rise and cool down very quickly. Ice crystals and water droplets form, from which a thundercloud eventually forms. The rising water droplets collide with the existing droplets. This creates an electrical voltage.
If it exceeds a certain threshold, a gigantic short circuit occurs. The lightning discharges within the cloud or between the cloud and the ground. Incidentally, it never gets hotter on the earth's surface than in a lightning bolt, at least for natural reasons.
Why does it flash?
The air around the lightning bolt heats up very quickly. This causes it to expand as in an explosion. Our ears perceive this sound pressure as a loud bang.
What exactly happens when you are struck by lightning?
The voltage on your body rises to several 100,000 volts. This results in burns and paralysis, possibly even cardiac arrest. Nevertheless, there are always cases where people survive. However, late effects such as memory impairment or eye damage can sometimes occur years later.
How can you protect yourself from a lightning strike?
Thunderstorms are best survived in a car or indoors. If you are caught out in the open, you should avoid trees, masts, fences or bodies of water and make yourself as small as possible - preferably squatting on the balls of your feet in a hollow in the ground. Your feet should be close together.
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