h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Yeah, I am. Now give me that ball, because it's going to rain and you're to come inside and watch television. No buts, inside NOW.

Some reading for a rainy day;

A5527514 - Rain

Aw... but Mr James, playtime isn't over until one o'clock

What did I say? NO Buts! Now get inside or I'll send you up to see Mr Sangster. And you know he doesn't like having his time wasted.

*mutters* Ok...

s'ok Matt, I told you to ignore it if you wished

'Acid rain is formed when chemical pollutants, like poisonous smoke from factories and fossil fuel power stations containing for the most part chemicals like sulphur dioxide (SO2), oxides of nitrogen (NOx) and - more rarely - carbon dioxide (CO2). These chemicals combine with the water vapour in the atmosphere creating, for want of a better phrase, acid rainclouds.'

The 'poisonous' here is irrelevant. I would word it as:

'Acid rain is formed when pollutant gases, present in smoke from sources such as factories, fossil fuel power stations, and the internal combustion engine (qv), containing for the most part chemicals like sulphur dioxide (SO2), oxides of nitrogen (NOx) and - more rarely - carbon dioxide (CO2) dissolve in water vapour in the atmosphere and eventually precipitate out as rain.'



'Acid rain is more of a problem in regions of the world where lakes and rivers are also polluted, as the water vapour evaporating from the large expanses of water already contains noxious chemicals. When acid rain falls it can be devastating, much like showers of vinegar, and can kill off plant life and leave forests, such as the Black Forest, Germany, in ruin'.


This is not true. Any pollutants present in the lakes remain, for the large part, dissolved. The pollutants are blown over in weather systems from the industrial regions of Europe - including GB

One of the problems is that it mobilises aluminium ions, naturally present in the soil, and which are toxic to animals and plants. (I mentioned this in somedody's Entry on 'Chemical Pollutants from the Industrial Combustion Engine' (or some such title). I can't remember if this as entered the EG yet but, if so, you should link to t <ok?

BigAl - have reworded that section, will add you as Chemical Consultant too

in Essex we used to get a very odd form of rain. It used to occationally rain sand

If the conditions were right, sand picked over the Sahara would be carried over europe and dumped on essex (and probably other places too). Always strange to wake up and find my car with a thin film of sand over it.

How very odd indeed. Are you sure it wasn't some strange Student Group to blame...

No, we get those sand showers here. The wind blows up from Africa, bringing it all with it for two weeks a year. We are due it any day soon.

Lovely Entry Matt. I don't usually have the patience for Entries this long, but this was a fine read.

<>

you do, will ensure you still get... perhaps?

Could this do with a section on the three main causes/types of rainfall (relief, convectional, frontal)? You've kind of got them in the entry anyway but I think they're worth mentioning. In fact I've been planning to do an entry just on those three for a bit now but since we've got a rain entry on the way you can do it.

Or I could write you a little section on it.

Or you could disregard this post and keep your entry as it is, since its quite long already.

DDD - Have taken your perhaps and made it a percertain

Iac - I might be able to squeeze something in regardnig those...I'll do some reading up on them first

Right, have included some brief information concerning the three main types of rain, cheers Iac

Great Scott! I've just used up all my paper printing this out - and not one chicken joke? *sigh* Well, you do mention chickens around about Noah's ark so I feel somewhat mollified.

Just kidding, or course - this is a great read.

>>The rain then soaks into the ground, or falls back into streams that flow into rivers<<
This implies that soaking into the ground is a dead end, but of course it is taken up by vegetation and returned to the air, or percolates through the ground and fills the streams less directly - or is pumped from the ground and sent up as fountains in Las Vegas.

>>When no rain reaches the ground through evaporation, it is called virga - a phenomena often seen in especially hot and dry desert areas.<<
Just fyi - virgas appear as dark columns underneath clouds that stop short of the ground. Also, and I don't know why this is, but you can smell rain from miles away in the desert long before it reaches you.

>>So cows, like any other sensible creature...<<
Cows are sensible creatures? I did not know this.

>>The source of this scent is in fact a chemical known as petrichor<<
I didn't know this either - thanks - seriously. This entry is just full of fascinating bits.

>>Cloud-seeding is not a brilliant way of creating rain, and it's probably just as productive to don a silly hat and dance about.<<
Actually, I heard a talk by some bloke in Texas, who reported it has been used with measurable success there. Isn't it an idea that Bernard Vonnegut (brother of Kurt) came up with? I think?

I'll have a more careful read-through this eve.

Top Notch!

Cheers pail. I'll wait until you've had a proper read to make any changes

Maybe I can get a chicken joke in there somehow...

Well, this is certainly a fine piece

Cloud seeding has been tried with various substances. In 1947, Bernard Vonnegut (scientist brother to the writer Kurt) sussed that silver iodide should be effective and it remains the preffered seeding agent today. The problem with seeding is not that it doesn't actually induce rain, because it does. The problem is that it requires clouds - so when there's already clouds it probably raining anyway, and when there's a drought and you'd really like to seed clouds, there's none handy.

>>Frontal rain occurs when warm air rises over cold air, forcing it to rise.<<
This is slightly confusing to me - perhaps 'when warm air meets cold air which is denser and forces the warm air to rise.'

>>Raining Cats and Dogs<<
You leave out the possibility that many occurrences of raining creatures are folklore. Having said that, I do find that some dead chickens have hit australian homes:
http://news.bbc.co.uk/2/hi/asia-pacific/4253209.stm
It seems likely the result beer consumption and access to a catapult - but it remains unsolved and one headline read 'It's raining hen'

Regarding raindrops bouncing because of their spherical shape - this implies an elastic interaction. Surely the raindrop, whatever its shape, breaks up on impact and some of the remaining energy drives smaller drops back into the air - or, you know, something like that.

Finally, you might want to offer this important warning about dining alfresco while it's raining - it will take an inordinately long time to finish your soup.



Great work

pail.

I'll get onto those points as soon as I can, and repost when I've addressed them

Rightio, I think I've addressed all the points made, all except the al fresco dining one, because I think that's an Entry in itself *hint hint*

Pheww...