On Mon, 18 Jun 2007 13:17:31 +0200, "David \(Normandy\)"
wrote and included this (or some of this):

As a reckless teenager in the 70's I used to have some fun with a mixture of
concentrated nitric and sulphuric acids. A drop or two of a certain cough
remedy and you've got the loudest 'bangers' on November the 5th ;-) Just
don't drop them!

Ammonium Tri-Iodide was good fun, too.


We used to drop it around the lab floors and let it dry out in blobs.
Frightened the kecks off a few cleaners sweeping up the next morning.





--
®óñ© © ²°¹°-°³

Ammonium Tri-Iodide was good fun, too.

We used to drop it around the lab floors and let it dry out in blobs.
Frightened the kecks off a few cleaners sweeping up the next morning.
--
®óñ© © ²°¹°-°³

Yes, fond memories of the stuff. When doing "A" level chemistry I made some
and it ended up all over the benches. My chemistry partner came in and
tossed her book onto the bench "BANG" and a small black hole in her book!
The chemistry lecturer came trotting to the back of the lab, and thinking
fast I exclaimed - "Sir - there was a big bang when she put her book down!".
"Yes!" said the lecturer, "Some idiot has made ammonium tri-iodide" and
looked at me suspiciously. Got away with it though.

Also had fun with the stuff at the paint factory. A little blob on the power
button of a big machine. The bloke came to start up to his machine and
pushed the 'ON' button - 'BANG' - He got the site electrician looking at his
machine for ages and was baffled how he got such a big "electrical" shock!

David.

On Mon, 18 Jun 2007 14:26:36 +0200, "David \(Normandy\)"
wrote and included this (or some of this):

Ammonium Tri-Iodide was good fun, too.

We used to drop it around the lab floors and let it dry out in blobs.
Frightened the kecks off a few cleaners sweeping up the next morning.
--
®óñ© © ²°¹°-°³

Yes, fond memories of the stuff. When doing "A" level chemistry I made some
and it ended up all over the benches. My chemistry partner came in and
tossed her book onto the bench "BANG" and a small black hole in her book!
The chemistry lecturer came trotting to the back of the lab, and thinking
fast I exclaimed - "Sir - there was a big bang when she put her book down!".
"Yes!" said the lecturer, "Some idiot has made ammonium tri-iodide" and
looked at me suspiciously. Got away with it though.

Many moons ago, when I started in a Path Lab, we used to wash out
glassware etc with detergent, hot water and bottle brushes, followed
by a rinse with ether before draining (to help with the drying, I
suppose)

A shedload of ether got left in the large sink and then the
Pathologist came in and tossed his fag-end into it.
That was a good day, too.


--
®óñ© © ²°¹°-°³

"Tom" wrote in message
...
David (Normandy) wrote:
The kids
were highly impressed with magnesium ribbon burning in pure oxygen -
they were blind for a while with "welders arc eye" but what the hey.

You might know about chemistry, but you know nothing about welding. Arc
Eye (photokeratitis) is a UV burn to the cornea (often confused with the
much worse "flash" which is a UV burn to the retina).

Had you given those children Arc Eye you would have found youself in
court.

Tom

I was using "arc eye" as a grammatical simile, a figure of speech to
describe a flash of light that was so intense it left everyone who was
watching partially blind for several minutes. It is common in chemistry
classes to demonstrate magnesium ribbon burning in normal air (with 20%
oxygen) which is very bright. In fact burning magnesium powder used to be
used as the flash in old plate photography. The flash produced when burning
magnesium in 100% pure oxygen is somewhat more extreme.

David.

"David (Normandy)" a écrit dans le message de
...

"Mary Fisher" wrote in message
t...

"David (Normandy)" wrote in message
...

The story you read sounds as though it were found in a sensational red
top,
professional gardeners still recommend the use of leached soot and
leached ash.

Mary

I can't remember where I read it now. I guess it makes sense if it is
left out in the rain to allow the noxious salts to leach out before it
is used on the garden. The problem only exists with coal ash/soot and
not wood ash/soot of course. Coal can contain all manner of toxic
minerals including arsenic, mercury, cadmium etc

David.

But only in very small quantities. Supposing they were absorbed by
plants - it would be in even smaller quantities and we wouldn't eat all
the plant anyway ...

I always leave wood ash in the open and wouldn't use it until it's been
rained on, it contains very caustic salts which can burn flesh and plants
until they're converted to the hydrated version.

Mary



Do I detect a fellow chemist? Potassium oxide (K2O) produced in the
burning, getting hydrated to become potassium hydroxide (KOH) which upon
exposure to carbon dioxide in the air eventually becomes potassium
carbonate (K2CO3).

To be chemically pedantic, it's bicarbonate (KHCO3).

The pre-war (WW2) gardeners' "bible", Gardeners Enquire Within, was very
much into soot. Enviro-friendly leaf mould was frowned upon.

I guess some of the components of soot would be insecticidal and/or
fungicidal, like coal tar spray (roses used to be easy to grow disease free
in big towns).

Regarding heavy metals, it's all in the dose. A kilogram of pristine soil
could contain a few micrograms of almost every element in the periodic
table, and arsenic is close to or above current safe limits in many parts of
the world. Sewage sludge, which contains some heavy metals, is dispersed in
a calculated manner. Gardeners don't have access to an analycal laboratory,
so the best advice is use soot and ashes, but use common sense and don't
overdo it.

Regards


David