response 150 of 365:

Oct 31 14:46 UTC 2000

        I've seen some awfully convoluted addresses before.  When designing
a db, it's always best to allow considerable leeway in the field length.

response 152 of 365:

Oct 31 22:33 UTC 2000

Two "address" fields is prety standard.  Essential for "123 Any Street",
"Suite 500".

response 154 of 365:

Nov 1 19:08 UTC 2000

Unless you're planning to have (literally) billions of entries in your tables,
you're almost certainly better off making your address fields much bigger than
you ever expect to need them.  You're far more likely to run into hassles and
errors dealing with field size limitations than tables that are too large.

response 156 of 365:

Nov 1 22:32 UTC 2000

I have a random short question for people:
Recently I've been heating up a lot of water for tea in the microwave.
Sometimes it gets really hot, but isn't boiling when I take it out of the
microwave, but then when I put the tea bag in, it starts bubbling all over
the place. Why?

response 158 of 365:

Nov 1 22:47 UTC 2000

There's a term for that, and I forget... It could happen on the stove, too,
but is much less likely to. It was on some TV science show I saw it explained,
maybe TV Food's Good Eats (with Alton Brown... that guy kicks ass, a cooking
show where every recipe's scientific properties are explained).

Anyway, back to the question. I'm sure I'll get the details wrong, but it has
to do with surface tension. In order to break the surface tension, it's not
enough that the water be at 212F... it can be somewhat more than that. Water
won't vaporize at the boiling point without help. Usually, imperfections in
the cooking surface are enough to create eddies of cold and hot water, but
when water is heated in the microwave, it needs more rocks to eddy around in
order to avoid "superheating" (that's the term), because it heats up so much
faster. If you use a ceramic mug or cup, odds are that the imperfections in
the internal surface aren't nearly enough to cause bubbles to form.
Superheating usually only takes place in clear, fairly pure liquids (esp.
water), and is more likely to occur when the heated liquid isn't being
jostled (creating eddies, breaking the surface tension, etc.).

Ways to avoid it: Use a mug with a graded internal surface, put some
micro-wave safe utensil in the mug as it's heating (gives someplace for the
bubbles to gather), make sure the microwave has a rotating tray, bump the
microwave before opening it.

The danger (this was used in that notorious McDonald's suit): Superheated
water is obviously hotter than expected, and suddenly breaking the tension
by picking up the mug could result in a tiny explosion, as all those really
hot molecules that have been trying to vaporize do so all at once. That
doesn't really happen very often, though (or you'd be hearing this explanation
more often ;} ).

response 160 of 365:

Nov 1 22:58 UTC 2000

Hey, my explanation wasn't far off. Here's a more professional answer:
There is a story circulating by email about a 26 year old man who heated a
cup of water in a microwave oven and had it "explode in his face" when he took
it out. He suffered serious burns as a result. Is this possible and, if so,
how did it happen? -- JJ, Kirksville, Missouri

Yes, this sort of accident can happen. The water superheated and then boiled
violently when disturbed. Here's how it works:

Water can always evaporate into dry air, but it normally only does so at its
surface. When water molecules leave the surface faster than they return, the
quantity of liquid water gradually diminishes. That's ordinary evaporation.
However, when water is heated to its boiling temperature, it can begin to
evaporate not only from its surface, but also from within. If a steam bubble
forms inside the hot water, water molecules can evaporate into that steam
bubble and make it grow larger and larger. The high temperature is necessary
because the pressure inside the bubble depends on the temperature. At low
temperature, the bubble pressure is too low and the surrounding atmospheric
pressure smashes it. That's why boiling only occurs at or above water's
boiling temperature. Since pressure is involved, boiling temperature depends
on air pressure. At high altitude, boiling occurs at lower temperature than
at sea level.

But pay attention to the phrase "If a steam bubble forms" in the previous
paragraph. That's easier said than done. Forming the initial steam bubble into
which water molecules can evaporate is a process known as "nucleation." It
requires a good number of water molecules to spontaneously and simultaneously
break apart from one another to form a gas. That's a rare event. Even in a
cup of water at several degrees above the boiling temperature, you might have
to wait minutes before such a rare event occurred. In reality, it usually
occurs at a defect in the cup or an impurity in the water--anything that can
help those first few water molecules form the seed bubble. When you heat water
on the stove, the hot spots at the bottom of the pot or defects in the pot
bottom usually assist nucleation so that boiling occurs soon after the boiling
temperature is reached. But when you heat pure water in a smooth cup using
a microwave oven, there is virtually nothing present to help nucleation occur.
The water can heat right past its boiling temperature without boiling. The
water then superheats--its temperature rising above its boiling temperature.
When you shake the cup or sprinkle something like sugar or salt into it, you
initiate nucleation and the water then boils violently.

Fortunately, serious microwave superheating accidents are unusual--this is
the first injury I've ever heard about. You could minimize the chance of this
sort of problem by deliberately nucleating boiling before removing the cup
from the microwave. Inserting a metal spoon or almost any food into the water
should trigger boiling in superheated water. A pinch of sugar will do the
trick, something I've often noticed when I heat tea in the microwave.
 
http://rabi.phys.virginia.edu/HTW//microwave_ovens.html

response 162 of 365:

Nov 2 00:47 UTC 2000

You shouldn't make tea with superheated water anyway. It is too hot.
Tea should be made with water below the boiling point. Air is driven
out of the water when heated to too close to boiling, which makes the
tea not taste quite as good. 

However in regard to boiling and superheat, etc, the explanation by
brighn is essentially correct. 

response 164 of 365:

Nov 2 16:05 UTC 2000

Personally, I like the strategy of putting a little sugar in the water ...
tea made with boiling water tends not to be as sweet (in my experience). It's
definitely blander than tea made with close-to-boiling (say, 190F) water.

response 166 of 365:

Nov 2 23:29 UTC 2000

Can anyone recommend a very simplified DOS-based spreadsheet that only adds
rows and columns, no other fancy math, no charts, no graphs?  It would save
typing in the month names so many times, which I have to do if I use my little
database program to keep track of monthly expenses and then do subtotals. 
The other option is to continue with paper and pencil and a calculator, and
write in month names only once, but then have to calculate each row and
column separately (i. e., enter each amount twice).  
Does DOS possibly have a function like this built-in?

response 168 of 365:

Nov 3 01:38 UTC 2000

I can boil plain water in the kitty cooker all day and the most that happens
is the water level in the cup drops. If I put in coffee or tea or anything
else it promptly boils over and goes all over the place. The time-to-boil is
pretty much the same either way as far as I can tell.

response 170 of 365:

Nov 4 21:22 UTC 2000

Is this a calculator?  The matrix calculators seem to add matrix A to matrix
B, rather than adding rows and columns within a matrix.  

response 172 of 365:

Nov 5 17:37 UTC 2000

You can dispense with the Hz information, since your power source is 
presumably the same or close enough not to matter for all the options, 
and likewise, your source voltage is likely the same for all three.  
(Besides, those are for the user's information regarding the required 
source, whereas the wattage is how much power the appliance draws, which 
is what is relevant to the cost.)

So:
        Stove:  6.9 KW/9.9 KW   (I'd guess the smaller number is the stove, 
larger is oven)
        Micro:  1.15 KW
        Crock:  75 W

Since the heat used is directly converted from the electrical energy, and 
since the amount of heat required to boil the water should be relatively 
static, the cost factor is directly determined by the relative efficiency 
of the appliances.  In other words, which one wastes the least amount of 
energy in heating the water?

Since the microwave has that big motor in it which sounds like a fan when 
you run it, you can assume that the energy it takes to run that is not 
necessarily going directly into heating the water.  Major inefficiency.  
However, that may be balanced out by the efficiency of the microwaves 
themselves versus the heating element on the stove or in the crockpot.  
Especially when you consider that it will take 2 minutes or less to boil 
2 cups in the micro versus several minutes on the stove, and much longer 
in the crock.  Since you say the crock doesn't really even boil, then you 
may want to remove it from consideration.

Now we have all the relevant information.  The micro draws 1.15KW to the 
6.9KW of the stove.  Assuming a constant rate of power draw during 
heating, the determining factor is the time required.  Since the micro 
draws less power per unit of time, *and* since it heats the water to the 
boiling point faster than the stove, the obvious answer seems to be the 
micro.

Did I miss anything?

response 174 of 365:

Nov 5 19:16 UTC 2000

        The oven will more than likely be 240 volt, drawing power from
both legs of your electrical line to the house.  The meter spins to 
measure the leg with the greatest draw at the time.  Therefore, with
a balance across the legs used by the electric oven could be more
efficent than you think.
        Still electric oven element on-time would seems to up to 10x 
microwave on time, along with maybe that 9.9kw draw verseus 1.15kw
draw during on-time.