Agreed. The bug bombs do provide a good test for the propane detector.

"Rosalie B." wrote in message
...
x-no-archive:yes
Steve Christensen wrote:

In article , Rosalie B.
says...

x-no-archive:yes "Paul" wrote:

Errr....why not just go buy a chunk of dryice, toss it in and close
the
boat up?

One extra Oxygen molecule.

But it's not available is it? I thought it would be bound up and
unusable.
We spray it on a fire to choke it out so I figured it may have oxygen
but
it's not available. For that matter, water has oxygen too doesn't it?
But
you can't breathe it since it's not available.

I may be wrong ... I'm just wondering.

Carbon dioxide (from dry ice) is a simple asphyxiant. If it displaces
the oxygen in the air it will kill you, but it takes quite a bit of
it. You can be exposed to 30,000 ppm for 15 minutes and still be OK.

Carbon monoxide at 1500 ppm may lead to death, and the 15 minute
exposure limit is 35 ppm for an hour. This is because without the
extra oxygen molecule, CO has a 200 to 300 times great affinity for
hemoglobin than oxygen does. So even if there is enough oxygen
present, the CO will kick it off the hemoglobin and you will die. So
it isn't just a simple asphyxiant any more.


Roselie is correct about the CO being more than an asphyxiant. But the
object
of all this is to kill roaches, right? It's been awhile since college
zoology,
but I don't think roaches even have circulatory systems, let alone
hemoglobin.

I have frozen roaches in liquid nitrogen (when bored during a late night
in the
lab) only to have them thaw out and crawl away. Hardy little beasts.
Does
anyone even know whether depriving them of oxygen (with CO, CO2, N2,
whatever)
will kill them? I bet it's damn hard to do.

I used to teach middle school science and I asked the 7th grade
students to make an insect collection. In the old days, we used
carbon tet to kill them, but that's not available anymore because of
the ozone layer thing. So the kids had to freeze them. Unfortunately
some insects are very hard to kill by freezing - it was quite common
for the wasps to come to after having been mounted in the collection
box - and boy were they mad!!! A determined wasp could sometimes get
off the pin. We didn't get roaches much.

Ticks (which aren't insects of course) are also hard to kill and we
would occasionally drown them or the children would pick them off
their horses and kill them by zapping them with the end of the
electric fence.

I think the boric acid is really the best solution which offers the
least possibility of your killing yourself. or blowing up your boat
(those insect bombs are often quite flammable when the propellant is
propane).

grandma Rosalie