# What in heaven's name is the 'Water Triple Point '?

• Cortazar
In summary, water has a point in its temperature and pressure where it can be a solid, liquid, and gas.f

#### Cortazar

What in heaven's name is the "'Water Triple Point"'?

And besides all the theory behind it, could you posit an experiment to prove it?

It is the only point in the P,T plane where all three phases of water (solid, liquid, and gas) can coexist in equilibrium.

as for an experiment, well you would need a box of some sort with water inside, where you can carefully control the temperature and pressure, then by adjusting both to the required points, you should be able to see water go from liquid to solid to gas and back to liquid, only making slight changes in the conditions

heres a picture that shows the conditions at the point itself
http://www.sv.vt.edu/classes/MSE2094_NoteBook/96ClassProj/examples/trip_pt1.jpg [Broken]

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And besides all the theory behind it, could you posit an experiment to prove it?

Prove WHAT?

Can you prove chess? Can you prove a car? Can you prove a dog?

And besides all the theory behind it, could you posit an experiment to prove it?

It is the temperature and pressure at which water is solid, liquid, and gas.

Someone in my high school chemistry class produced this state, so I have seen it with my own eyes. Ice floating in boiling water.

Ice floating in boiling water.

Cool.

Is water the only (or one of a rare breed of) substances that has a triple point?

Is water the only (or one of a rare breed of) substances that has a triple point?

Table of triple points (Wikipedia)

Factoid: the triple point of water is part of the definition of the Kelvin temperature scale. It's defined as 273.16 K, exactly.

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Not at all. The Wiki article on triple point includes a list of (some) materials with their triple points.

edit: Sorry. jtbell was faster.

Cool.

Is water the only (or one of a rare breed of) substances that has a triple point?

Apparently not the only one: . I'm having some laughs, I used youtube as a search engine for once, almost unbelievable.

Edit: both jtbell and nasu have been faster.

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Table of triple points (Wikipedia)

Factoid: the triple point of water is part of the definition of the Kelvin temperature scale. It's defined as 273.16 K, exactly.

Not at all. The Wiki article on triple point includes a list of (some) materials with their triple points.

edit: Sorry. jtbell was faster.
Apparently not the only one: . I'm having some laughs, I used youtube as a search engine for once, almost unbelievable.

Edit: both jtbell and nasu have been faster.

Excellent demonstration of the triple point of answers

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