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BuffaloBoyHowdy t1_j5wfkzm wrote

Reply to comment by Ausoge in How hot is the steam coming out of nuclear power plants? by ivy-claw

This. You can't really see steam itself. All that white stuff is water vapor. Look closely at a kettle with boiling water. As the mist comes out of the spout, there should be a clear space at the opening, that's the steam. It quickly condenses into water vapor, which is what you see. Don't stick your finger in it.

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ramriot t1_j5x57pm wrote

Yup, this is why Live Steam is so damn dangerous. If a high pressure steam line develops a crack the escaping steam can sound like a banshee on heat but is also completely invisible. The jet is just hanging out there waiting to slice off your limbs or scald you do death.

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Rangoras t1_j5yyang wrote

If we ever had a super heated steam leak in the engine room we were trained to grab a broom or other stick and wave it in front of you from floor to above your head while moving slowly. When the broom was cut in half by the invisible steam jet you found the general leak location.

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unclepaprika t1_j5wiewo wrote

2 steps forward, 1 step back. Didn't we just establish that steam IS water vapor?

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lurkandpounce t1_j5ym84p wrote

Steam is water in a gaseous form and invisible.

Water vapor is made up of water droplets that are so light they are carried by the air currents.

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BuffaloBoyHowdy t1_j5zc5xr wrote

Steam is water vapor; water vapor is not steam. A square is a rectangle; a rectangle is not a square. Both are parallelagrams; but a parallelagram isn't a square or a rectangle. A thumb is a finger but a finger is not a thumb. Things are just like that sometimes.

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[deleted] t1_j5wmz6o wrote

[removed]

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TrappedInASkinnerBox t1_j5wy37c wrote

On the engineering side at least the gaseous phase is definitely referred to as "steam" not "water vapor"

Saturated steam, superheated steam, etc

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mightyn0mad t1_j5x4ezm wrote

Seconded. Steam is steam, we do not call it water vapour. Depending on conditions it can be saturated steam (the one that looks white) or superheated steam (the colourless one)

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Angdrambor t1_j5wob3l wrote

>Steam is droplets of liquid water suspended in the air which appears white due to light scattering.
>
>Vapor is colorless and transparent. You cannot see it.

When I took thermo in my country, we refered to it the other way around. Steam is the invisible gas phase, "vapor" is the white cloud of liquid droplets.

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lichlord t1_j5wrrfh wrote

Was it thermo taught by scientists or engineers?

Thermo in chemistry and physics usually simplifies steam into gaseous water.

In engineering thermo courses the focus is less in phases and equations of state, and more on work and transformations. Engineering thermo will often distinguish between wet, dry, and superheated steam.

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CYWNightmare t1_j5x2odw wrote

I thought rainbows were water vapour with light hitting it so wouldn't I see water vapour to an extent?

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