Roger wrote:
On Sun, 05 Feb 2006 17:50:04 GMT, Richard Lamb
wrote:

Might we go a bit farther?

The reason I ask is that I've seen people take big lungfuls of Helium,
which (obviously) doesn't produce the same effect.

A really big lung full can make you light headed in a hurry, but
beyond that?


Can someone explain why N is such a disaster but He doesn't?

"I think" it has to do with the partial pressure of He compared to N,
but I really don't know.

Partial Pressure of a gas is what the pressure would be if all the
other gasses were removed without changing the volume.

Equal volumes of gas at the same temperature and pressure have
equal numbers of molecules (Avogadro's law). So no, that isn't
the explanation.

There are warnings about inhaling He, but
I've not heard of any reactions like those of N2.

The warnings I have heard regard hydrocarbon contaminants
like compressor oils, putting the huffer at risk for chemical
pneumonia.

Still, He is used
as an N2 replacement in diving air at times to reduce the likely hood
of getting the bends on deep dives.


One presumes contaminants like compressor oils are filtered out
when the Helium is intended for that purpose, something one might
not bother to do for balloons.

--

FF