What would steam look like...

…if it were somehow hypothetically released from containment without condensing, or if you could see inside a high-pressure steam line without breaking containment? Would it be an invisible gas? Is high-pressure steam actually a superheated liquid while under pressure? Got to thinking about this today while stuck in traffic.

I think it would just be a gas.

steam is invisible.

Dead stim!

is not.

If you look at a steam whistle (or even a teapot) the steam is invisible for the first second until the vapor condenses.

Here ya go…

Ah, yeah, I didn’t think about that. Neat video.

Superheated water vapor is indeed invisible, as people have found to their sorrow when unexpectedly encountering broken steam pipes. :eek:

At a high enough pressure and temperature water becomes a supercritical fluid, which cannot strictly be called either a gas or a liquid. However in most applications of steam it is a gas.

High or low pressure steam can be superheated or not superheated. Depends temperature.