response 15 of 98:

Dec 31 03:01 UTC 1998

I don't know the chemical names or color numbers of the indicators in
cabbage or delphiniums so haven't been able to look them up (my sources do
not give information based on 'cabbage' or 'delphinium'). However all
indicators are dyes that contain several reactive groups that make them
acidic or basic, such as R-COOH, R-SO3H, or R-OH (on a benzene ring),
which are acidic, and R-NH2 or R=NH, and some others, which are basic. (R-
is the general symbol for the rest of an organic molecule. The rest of the
molecule has alternating single and multiple bonds, which allow electrons
to slosh back and forth. The colors are a consequence of the frequencies
at which the electrons "resonate" on the structure, and the colors are
changed by whether a group is, say, R-COOH or its ionized form R-COO-, or,
say, R-NH2 or its ionized form, R-NH3+. ; 

Of course, there are a lot of dyes that are not indicators, such as the
flavenoids and carotenoids that you mention. These lack the acidic/basic
groups, but have the alternating single and multiple bond structures.

response 17 of 98:

Jan 1 18:46 UTC 1999

Yes, Detroit planes usually take off to the southwest before turning northwest
to fly over Ann Arbor.  Jim gueses actual distances might be 20% longer, but
the factor probably depends on total distance.

What makes purple green beans turn green when cooked?  Is the dye degraded?

Jim concludes that 2 people travelling in a car (with freight) is more fuel
efficient than 2 people in a plane.

response 19 of 98:

Jan 3 20:44 UTC 1999

I got a book on dye plants (written by botanists) and they mention that
tannins (brown) are formed from other dye molecules and are found mainly inteh
bark and near wounds and in galls.  I was wondering what function dye
molecules perform for plants, other than in flowers and fruits, and it looks
like they may react with invasive organisms (those extra electrons could mess
up the metabolism of some monocellular creature, just like they messed up my
skin when I husked black walnuts).  I have also read that saffron protected
cloth from insects, and indigo prevented mildew.  Jim got a different VGA
monitor (not saffron colored but white):  'nothing happened' (he forgot to
plug it into a power source).  No problem seeing just a few characters on this
one, no dimming effect.  Maybe the other monitor is going bad.

response 21 of 98:

Jan 4 04:11 UTC 1999

I could not think of any functional reason for roots or sap to be colored.
Today I mixed up some more old lime, checked with pH paper that it was at
least pH 11 (bright blue), and then put a piece of pickled red cabbage into
it.  The cabbage quickly turned purple then blue and then exuded an emerald
green.  The cabbage itself remained purply-blue.  My book shows the transition
from red purple blue turquoise (missed that) to green, with green at the high
end of the pH.  When my pH paper runs out, all I have to do is buy a red
cabbage (hopefully it will also work without prior fermentation to the red
range of acidity).  The cabbage has been going about two weeks and tastes as
sour as pure vinegar so I refrigerated it.  I can use just the juice for pH.
The corn itself (to which I add the lime water) also turns from an orangy to
a dark green color, presumably the red turns to blue and the yellow gets
stronger or at least persists.  The kernels are bright yellow, no green. 
There is also yellow, red, or blue corn, but apparently corn is not naturally
alkaline, so no emerald-green corn.
        Many vegetables come in either purple or green versions, perhaps this
is due to variations in alkalinity (at higher pH the purple goes to green):
green beans, peppers, brussels sprouts, cabbage, lettuce, chard/beets, turnip,
red versus white runner bean seeds, onions, garlic, eggplant (white or purple,
no yellow pigment?), purple carrots were the original color, gooseberry, red
or yellow cherries (missing pigment here?), red or white currant.  Pink or
white grapefruit.

response 23 of 98:

Apr 6 02:42 UTC 1999

Usually they operate by counting cycles on the input line.
However, I have found that spurious signals such as high levels
of RF can cause them to count fast.  You may have a similar problem.
I don't know of a cure.  Battery-powered quartz clocks are cheap
and don't have this issue, so if you don't need to read them in
the dark, you might want to get a couple.

response 25 of 98:

May 15 00:06 UTC 1999

I discovered while making tortillas that if you are too busy to finish making
them after you soak in CaCO3, boil for an hour, and then rinse 25 times, and
you leave them overnight soaking in the refrigerator in clean water, you no
longer have the caustic effect when you eat them.  There must be alkali
trapped inside after boiling that gets released slowly.  But the steam from
boiling the corn is hard on the nose.

response 27 of 98:

Sep 20 05:57 UTC 1999

It works because that (and similar ones for cosine, etc) are the Taylor
series expansions of the function. There are such series for *all*
functions, and they are derivable by a relatively simple operation (if you
know calculus). Mathematicians have worked for hundreds of years on
deriving alternative way to express one function in terms of others. In
this case, it is the harmonic function being expressed as polynomials.
[The real answer to why it *works* is because they give the same value.
Less pedantically....an expression like sine(x) is just a shorthand for
some operations that give the ratio of the opposite side to the hypotenuse
for the an acute angle of a right triangle - the series is one such
arithmetic operation.] 

response 29 of 98:

Sep 21 06:25 UTC 1999

Yup.

response 31 of 98:

Oct 25 03:58 UTC 1999

In biology class the other day a couple of friends and I got to talking about
dissolving salt in water. Of course it forms Na+ and Cl- ions. Chlorine is
poisonous and sodium ignites in contact with water, but neither
of these reactions happens. Why? My guess was that since the ions have 
the same electron configurations as noble gases, they are nonreactive. Is
this right?

On a related note: Acids attack things because an H+ has no electrons and
therefore can get closer to the outer electrons of other atoms and "pull"
them away. (At least, this is what I was told in an introduction to chem
class last year.) Why are bases, with [OH]- ions, caustic?

response 33 of 98:

Oct 26 04:01 UTC 1999

We did an "experiment" in chemistry a few weeks ago in which we filed pennies
to expose the Zn inside, then put them in HCl solution overnight. If I
remember correctly, it produced H2 gas and ZnCl (or perhaps it is ZnCl2
<oddie does not have a periodic table with him at the moment>), though the
copper did not appear to react at all. This would seem to be a  case of the
H+ ion actually stripping an electron off another atom, forming Zn+ ions
that then were attracted to the Cl- in solution. (I believe ZnCl is ionic
because it consists of a metallic and a non-metallic ion, but I could
be wrong.) In this year's chem class we are only now getting to formation
of molecular bonds; we spent much of the first quarter doing "introduction
to quantum theory." Our teacher offered us some extra credit if we could
solve the Schrodinger wave equation for neon over the weekend ;-P

response 35 of 98:

Oct 26 19:57 UTC 1999

The way I heard it, you don't get H+ ions. Instead you end up with H3O+ ions,
with that loose proton attaching itself to a water molecule.

response 37 of 98:

Nov 5 05:14 UTC 1999

You're right Andrew.  I reread the chapter in the chem textbook on acids and
bases last night. Wouldn't the third bond on H30+ be weaker than the original
bonds forming H2), though? What is the charge difference between the ends
of a water molecule?

I have been trying to figure out the chemical formula of isopropyl alcohol,
the stuff sometimes sold as "rubbing alcohol." An alcohol has a formula
of the form R-0H, says the textbook, and propane is a 3-carbon hydrocarbon
so my guess is this:

 | | |
-C-C-C-OH
 | | |

What does "iso" (Latin for "the same," is all I know) mean in this context?
Could you have an alcohol based on an alkene, alkyne or even a benzene
ring, rather than an alkane?