# What would steam look like... **URL:** \ **Category:** Factual Questions\ **Created:** [May 22, 2014, 12:55am UTC](https://boards.straightdope.com/t/what-would-steam-look-like/688975 "2014-05-22T00:55:58Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![RearEchelon](https://avatars.discourse-cdn.com/v4/letter/r/b4bc9f/32.png) [@RearEchelon](https://boards.straightdope.com/u/RearEchelon)\ **Post date:** [May 22, 2014, 12:55am UTC](https://boards.straightdope.com/t/what-would-steam-look-like/688975/1 "2014-05-22T00:55:58Z")
…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. ---
**Author:** ![robert\_columbia](https://avatars.discourse-cdn.com/v4/letter/r/e79b87/32.png) [@robert\_columbia](https://boards.straightdope.com/u/robert_columbia)\ **Post date:** [May 22, 2014, 12:57am UTC](https://boards.straightdope.com/t/what-would-steam-look-like/688975/2 "2014-05-22T00:57:20Z")
I think it would just be a gas. ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [May 22, 2014, 1:15am UTC](https://boards.straightdope.com/t/what-would-steam-look-like/688975/3 "2014-05-22T01:15:40Z")
steam is invisible. Dead stim! is not. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [May 22, 2014, 1:19am UTC](https://boards.straightdope.com/t/what-would-steam-look-like/688975/4 "2014-05-22T01:19:45Z")
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… [![](https://img.youtube.com/vi/73txXT21aZU/maxresdefault.jpg "Working Model of Stephenson's STEAM ENGINE made of GLASS ! Rare!") ](https://www.youtube.com/watch?v=73txXT21aZU) ---
**Author:** ![RearEchelon](https://avatars.discourse-cdn.com/v4/letter/r/b4bc9f/32.png) [@RearEchelon](https://boards.straightdope.com/u/RearEchelon)\ **Post date:** [May 22, 2014, 1:24am UTC](https://boards.straightdope.com/t/what-would-steam-look-like/688975/5 "2014-05-22T01:24:20Z")
> [@Joey\_P](#): > > 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… > [http://www.youtube.com/watch?v=73txXT21aZU](http://www.youtube.com/watch?v=73txXT21aZU) Ah, yeah, I didn’t think about that. Neat video. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [May 22, 2014, 1:29am UTC](https://boards.straightdope.com/t/what-would-steam-look-like/688975/6 "2014-05-22T01:29:13Z")
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. ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [May 22, 2014, 4:26am UTC](https://boards.straightdope.com/t/what-would-steam-look-like/688975/7 "2014-05-22T04:26:17Z")
> [@RearEchelon](#): > > …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. High or low pressure steam can be superheated or not superheated. Depends temperature.