| Congratulations from The Amazing
Randi
Forrest,
Please convey to Shawn my congratulations on the SAS success.
I know how much hard work went into getting it all off the
ground, and it’s really paid off.
James Randi.
Shawn Carlson was delighted to receive this message from
The Amazing Randi. Editor.
Watch for This New Article in
TCS
Editor,
This is in regard to your Nov 18th, 2005 article, "The
Quest for a 21st Century Prototyping Board" (The
Citizen Scientist, 18 November 2005).
As an electronics designer, I am regularly looking for PCB
prototyping systems which can save me development time. I
would like to call attention to one system in particular which
has significantly
increased my productivity; Snap-Apart prototyping systems
from Bellin Dynamic Systems
Inc.
I have found these kits especially handy when adapting small
SMD parts like SOT-23 and TSSOP to DIP. They are not especially
cheap, but I have found them to be a worthwhile investment
and I am sure other SAS members will appreciate them.
These kits are also available through Mouser.
Ryan Shuttleworth
Prototyping electronic circuits using surface mount technology
(SMT) can be intimidating for the novice. This is why we were
glad to publish the "The
Quest for a 21st Century Prototyping Board." Ryan's
letter suggested the obvious, so we contacted him to ask if
he could provide a product review. he agreed. Watch for it
in the next issue of TCS. Editor.
Bumblebee Stingers?
Editor,
The "Gallery"
for the 18 November 2005 issue of The Citizen Scientist
is about bumblebees by David R. Brooks. There is an error
in the statement: "...queen and drone bumblebees are
equipped with a stinger,...". Since the stinger in the
bumblebee (and any other stinging hymenopterid) is
a modified ovipositor, the drone (male) cannot sting.
Tom Gartner
Reader Tom Gartner is correct. The statement should have
read, "Worker [not queen and drone] bumblebees are equipped
with a stinger, but they rarely use it against curious people."
The error is mine. Editor.
Transforming Hydrogen Sulfide into
Sulfur Dioxide?
Editor,
Shawn's alchemical magic for transmuting a silver coin into
"gold" is really neat. That's the first I've heard
of it. However I think he has led his correspondent a little
astray regarding the chemistry (without the "al")
involved.
The rotten egg odor is due to hydrogen sulfide (H2S),
not sulfur dioxide (SO2). SO2 has a
suffocating odor which can literally take your breath away
if you inhale a lung full of it. For all I know there may
be a bit of it formed along with H2S when an egg
is hard boiled and would contribute to the flavor, but I'm
quite sure the gold color is due to formation of silver sulfide
(Ag2S). After all, ferric sulfide (iron pyrite,
Fe2S3) has been rightly called "fool's
gold."
H2S is the culprit responsible for giving chem
labs their reputation for being malodorous. The classical
course in qualitative analysis involved separating and identifying
the metals in an "unknown" based on the properties
of their sulfides, and the H2S required was generated
by reacting ferrous sulfide (FeS) with dilute sulfuric acid
in an impressive piece of glassware called a Kipp Generator.
H2S is quite toxic, being comparable to hydrogen
cyanide in that respect. It's not as treacherous as cyanide
since its repulsive odor warns against over exposure Nonetheless
a few years back a technician at the University of Maine was
killed by over exposure to H2S when he entered
a tank to clean it out
I trust Shawn will pass along some of this information to
his correspondent. We wouldn't want her to be embarrassed
at the fair by some know-it-all (like me, I suppose) questioning
her chemistry.
Norman F. Stanley
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are welcome. Letters are subject to light editing to correct
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