Rain is wet and wonderful, right?
Droppeth-ing upon the place beneath – reviving the plants, bringing us water to drink.
Good, pure, wonderful rain – the freshest water on the planet.
Because of global warming, see. Full of acids and pollutants, like everything else we touch.
Another step towards certain doom.
A bit otherwise, that.
A drop of the real stuff
In Oz, rainwater runs off the roof into tanks.
For drinking when you run out of beer – to shower with, or top up the goldfish bowl. You wouldn’t use it if it wasn’t dinkum.
Yeah, sure – most of the time it’s clean and uncontaminated – a real life-giver.
Except something happens when it’s chucking it down.
That tangy smell you get from fresh rain?
You’re not imagining it, that’s the smell of earth riding up on microscopic bubbles of air, released from the impact of raindrops on the ground.
A bunch of researchers at Massachusetts Institute of Technology (MIT) have actually filmed it – used a high-speed camera to show a fizz like champagne bubbles popping into the air.
Which means minute traces of whatever’s in the earth are thrown up too – minerals, dust, bacteria. Tiny specks of stuff that are so small they rise and swirl in the tiniest eddy.
No bigger than a micron (a millionth of a metre), they ride along with all the other things that breed by dispersal – dandelion seeds, for instance.
Which is how you could get unlucky and come down with e. coli, staphylococcus aureus or some other bug. Enough to give you a nasty tummy ache.
Or that scary Ebola virus we keep hearing about – only 200 nanometres across – barely a 100,000th of a micron. Small enough to blow anywhere.
All from a single drop on the hard sun-baked earth.
Splash, splatter, splat
It gets messier with plants.
Each hit is like a mortar, smashing and fragmenting. Flinging out anything that might sit on a leaf – sap, pesticides, fluid from fungal parasites – and of course, more bacteria.
Some of it hits and sprays, reaching up and around the plant to 18 inches or more.
But leaves are free-floating, resilient, twisting in the wind.
Incoming raindrops weigh them down, spring-loaded, to catapult up and away into the blue – spinning and shattering into tinier fragments.
Particles so small they could ride the wind for thousands of miles and still never settle – viruses, small bacteria, fumes, soot, oil vapour, tobacco smoke, the works.
OK, so you like splashing round in the rain.
Coughs and sneezes spread diseases – and now you know how they got there. (Tweet this)
Better be careful, like grandmother says.
It’s a lot more than a cold you could catch.
Originally posted 2015-02-05 13:30:22.