Anyway, the original point was that red/blue marks
on taps stand for "hot"/"cold", not for "dangerous"/
"safe" (AFAICT, blue isn't routinely used to mean
"safe"). When suggested to devise a colour code for
"hot"/"cold" taps, LSD proposed a yellow/green code
meaning "dangerous"/"safe" instead. Then I pointed
out that the hot-water tap is not a danger if you
just heat tap-water to _usable_ levels and not to
crazy dangerous levels, so the dangerous/safe code
is only meaningful to those who apparently like to
live a risky life and routinely heat their tap-water
to dangerous levels.

No. What I am trying to point out (if you listen for a while), is that
it doesn't matter about OUR water temperature. Somewhere, sometime, when
someone was color-coding early faucets, he had hot water of some
temperature. *His* opinion on whether *his* hot water was dangerous is
the only opinion that matters in this discussion. Intuitive to you is
irrelevant. Intuitive to me is irrelevant. Intuitive to him is relevant.
Do you have any data on what a typical hot water temperature was when
the first red/blue faucet was made? I bet that the hot water was coming
straight out of a poorly regulated boiler, and was pretty dangerous at
that time. What has happened since, in the absence of time travel, is
irrelevant.

But we _know_ it wasn't the case that the colour
code was chosen to represent "danger"/"safe",
because that would have been red/green instead
of red/blue. The colours represent temperature,
not safety, and it's easy to see why: the former
is the straightforward association for hot/cold
water taps, the latter would be rather convoluted.
And that was my point.

"Richard" == Richard Herring <richard.herring@baesystems.com> writes:

But we _know_ it wasn't the case that the colour code was
chosen to represent "danger"/"safe", because that would have
been red/green instead of red/blue. The colours represent
temperature, not safety, and it's easy to see why: the former
is the straightforward association for hot/cold water taps, the
latter would be rather convoluted. And that was my point.

And why do you heat your tap-water to a temperature
you know can hurt you? You need to mix it with
cold water in order to use it, don't you? So why do
you waste energy and time heating it up to 70ºC only
to mix it with cold water to reduce its temperature
to say 40ºC?

Nathan> Of course, almost anything can have a reddish tinge under
Nathan> red lighting,

No. Black remains black, by definition.

Liquid nitrogen doesn't come out of the taps in my house. Dangerously
hot water does.

Javier> The normal temperature of the human body is just above
Javier> 35ºC,

It's 37 degrees Celcius, 98.6 Fahrenheit.

Javier> Real cold water feels sharp as a razor when you place your
Javier> hand under the faucet and let the water flow on it, after
Javier> a few moments you need to draw your hand away out of sheer
Javier> pain.

I don't feel it "sharp". That's again a linguocultural thing, I think.

"Nathan" == Nathan Sanders <nathansanders@verizon.net> writes:

No. Black remains black, by definition.

Javier> Things themselves do not have colour. They only reflect
Javier> light.

You're going to tell me that red-hot iron does not emit coloured light?

Javier> Possibly due to the wrong colour tuning of your
Javier> monitor. That "green" is bluegreen/turquoise/azure with
Javier> more blue than green, and not at all grass green. And,
Javier> anyway, green is a cool colour too.

You could say whatever you want. You can even claim that I'm blind
and I'm just doing Usenet with a Braille display.

Evidence?

Javier> And that yellow of usual fire always features reddish
Javier> tinges.

I don't think so. Given that perception is subjective, I don't think
there is any sense to argue around that. To me, flames are yellow.
That's MY perception.

Javier> Have you never had a barbecue or lit up a fire out in the
Javier> country?

The fire of charcoal is very dim. I can't tell if it's red or blue.
(It also depends on ventilation. A well prepared fire using charcoal
has bluer flames. Of course, the burning charcoal itself glows with a
orange colour, like "red-hot" iron.)

Javier> My hot-water tap is never dangerously hot, because I'm not
Javier> that rash and irresponsible.

That's YOUR experience, and that's quite different from MINE. Got it?

Fact: hot water from the tap *somewhere* *sometime* can be dangerously hot.

Are you going to refute that?

Javier> The colour code was not meant to be restricted to one
Javier> particular cultural area, but to be easily understood by
Javier> anyone without previous explanation.

And it fails that purpose.

Javier> (Now you'll tell me you would be unable to guess out the
Javier> meaning of the red/blue code...)

Yeah. I couldn't guess it. People taught me that colour code when I
was young. And most of the time, I don't depend on the colour coding.
I simply switch it on and see (by eye -- the steam) if the water
coming out is hot. And before seeing it, I simply guess that the tape
on the right hand side is cold water.

Fact: *not* everywhere hot water from the tap is
dangerously hot. Therefore, *not* everywhere marking
taps by means of associating "hot water" -> "danger"
is meaningful.

Fact: *everywhere* hot/cold-water taps are associated
with a difference in temperature. Thus, *everywhere*
marking taps as for temperature is meaningful.

Got the point now?

And why do you heat your tap-water to a temperature
you know can hurt you? You need to mix it with
cold water in order to use it, don't you? So why do
you waste energy and time heating it up to 70ºC only
to mix it with cold water to reduce its temperature
to say 40ºC?

To inhibit the growth of bacteria in the hot-water tank.

Nathan> Of course, almost anything can have a reddish tinge under
Nathan> red lighting,

No. Black remains black, by definition.

Hence the "almost" in the piece of my post that you quoted.

Fact: *not* everywhere hot water from the tap is
dangerously hot. Therefore, *not* everywhere marking
taps by means of associating "hot water" -> "danger"
is meaningful.

Fact: *everywhere* hot/cold-water taps are associated
with a difference in temperature. Thus, *everywhere*
marking taps as for temperature is meaningful.

Got the point now?

When will you post the blue-prints for your time machine? How was your
trip back into the past where you confronted the guy with a steam boiler
and told him that marking his faucet red for danger would confuse future
generations, who all knew that sophisticated temperature regulating
faucets would render their hot water safe?

In my corner of the world fire trucks are still greenish yellow, and
police lights are blue and white.

I know some people from (actually, emigrates form HK to) Calgary and
they never mentioned that "surprising" thing to me.

"Nathan" == Nathan Sanders <nathansanders@verizon.net> writes:

Nathan> Of course, almost anything can have a reddish tinge under
Nathan> red lighting,
No. Black remains black, by definition.

Nathan> Hence the "almost" in the piece of my post that you
Nathan> quoted.

"Almost anything" means "most things".

So, your statement implies
that "only a small proportion of things" do not have a reddish tinge
under red lighting.

I'm afraid there are so many black things that I won't consider that
to be "only a small proportion". The "almost anything" is thus an
inapropriate expression.

Nathan> BTW, any decision yet on whether ice is crystalline or
Nathan> not?

No.

That comment of yours is stupid and that doesn't
contradict my point at all: *everywhere* and
*everytime* hot/cold water is associated with
a difference in temperature; *not* everywhere
and *not* everytime hot/cold water is associated
with a difference in safety.

Got it _now_? Or need I repeat it again?