The Straight Dope 02/02/2007

The Straight Dope -- By Cecil Adams
http://www.straightdope.com

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THE STRAIGHT DOPE 02/02/2007

Dear Cecil:

In 2002 you said, "Long a target of fringe groups, fluoridation is
widely considered one of the great public-health achievements of the
last century." My wife has shown me a lot of Internet back-and-forth
suggesting a host of problems that can be blamed on fluoridation. Some
say fluoride is industrial waste and that the mining industry duped us
into thinking it's healthy so we'd want it in our water. So is fluoride
deadly or healthy, or do we just not know? --James B., Columbia,
Maryland

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Cecil replies:

Oh, we've got a pretty fair idea. Fact is, like a lot of things (Tylenol
and water come to mind), fluoride can be either good or bad for you
depending on how much you get. In small amounts the stuff is definitely
salubrious. Though a few holdouts still argue, most research I've seen
credits fluoridation with the sharp drop in tooth decay seen throughout
the developed world over the past 40 years. In the U.S., 67 percent of
those drinking public water get fluoride in it and tooth decay has
fallen 68 percent since the late 60s, leading the Centers for Disease
Control to call water fluoridation one of the top ten public-health
achievements of the 20th century. Too much of a good thing, on the other
hand -- and we're talking milligrams per kilo of body weight, not gallons
-- and you've got problems, ranging from stained teeth and upset stomach
to death.

Although fluoride's contribution to healthy teeth had been suspected
earlier, the guy chiefly responsible for getting people to focus on the
usefulness of having it in drinking water is Dr. Frederick McKay, who in
1909 began investigating a tooth discoloration so common among residents
of Colorado Springs that it was known as "Colorado brown stain." After
peering into the mouths of nearly 3,000 kids in the area and finding
that 87 percent had stained teeth, McKay and colleagues went on to
establish that (a) such teeth were unusually resistant to serious
cavities and (b) the cause of both phenomena was the naturally high
fluoride level in the local water supply. After further research showed
that one part per million of fluoride in drinking water reduced tooth
decay with minimal risk of stained teeth, Grand Rapids, Michigan, became
the first city to artificially fluoridate its water in 1945. Thousands
of other municipalities have done so since.

For more, see:
http://www.straightdope.com/columns/070202.html

STAFF REPORT

Dear Straight Dope:

I've seen a lot of movies that feature gun silencers, and got to
thinking about how they work. Are they really as effective as they're
made to look on the big screen? I've fired quite a few firearms, and
have a good idea for how loud they are in real life. I'm guessing that
it takes a pretty clever device to reduce the deafening "BOOM" of, say,
a .45 automatic to the discrete "thup" that you see and hear in the
movies. What's the scoop? How do gun silencers work? Are they legal? 
--RevMarTye  

SDSTAFF Bricker responds:  

Though Hollywood treatments of firearms aren't noted for their realism, 
silencers by and large are an exception   they work pretty much as
depicted, at least for the first few uses. Before we get into ways to
silence guns, though, it's useful to examine what makes them so loud.

You may think those metal thingies Jack Bauer loads into his weapon, or
would load if it were ever empty, are bullets. Not exactly. Strictly
speaking they're cartridges -- a bullet clamped in a casing. The bullet is
the projectile that's shot out of the gun barrel; the casing holds the
bullet, primer, and gunpowder together before the shot is fired. Pulling
the gun's trigger typically slams a pin into the rear end of the casing.
That ignites the primer at the base of the cartridge, which in turn causes
the powder to explode, releasing hot gas. The resultant high pressure
blasts the bullet out of the casing, down the barrel, and out into the
wild blue. Behind it, the hot gas from the explosion also emerges, no
longer confined to the narrow barrel. Just as a party balloon pops loudly
when ruptured, the escaping gas makes a loud bang. (The bullet, if it's
traveling faster than sound, may also contribute a mini sonic boom to the
mix).

For more, see: 
http://www.straightdope.com/mailbag/msilencer.htm

STRAIGHT DOPE CLASSIC - 03/30/1990

Dear Cecil: 

I want to start my own country. My question is, how do I go about this?
I assume it is illegal to buy land in an existing country and proclaim
sovereignty simply by virtue of ownership. Is there any way to avoid
this difficulty and either (1) buy some territory in an existing country
with the intent of seceding; (2) claim some previously unclaimed (or at
least not very heavily guarded) land; (3) settle an area that had not
existed earlier (e.g., a volcanic island); or (4) find some other way to
realize my dream of founding a nation where all people are truly equal,
the state respects individual rights, and free pizza delivery is
constitutionally guaranteed? The fate of a nation rests on your answer.
--James Hyder, Columbia, Maryland

Cecil replies:  

I'm used to it, James. There are several schools of thought on what it
takes to establish an independent state. One is that you're a nation if 
other countries recognize you as such. This approach has a certain
practical appeal, but from a philosophical standpoint it eats. It suggests
the minimum number of nations you can have is two, so each can
recognize the other. More important, it denies reality: if you look like a
nation and act like a nation, why should nonrecognition by a bunch of
foreigners prevent you from actually being a nation?  

OK, but what constitutes looking and acting like a nation? Opinions
differ, but some suggest there are four conditions: 

For more, see:
http://www.straightdope.com/classics/a3_300.html

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