The Triple Point

[Watch] Triple Point Turns Substance Into A Gas, Solid And Liquid All At Once

Observe: the triple point.

Yes, this liquid is boiling, freezing, and vaporizing simultaneously. It is an amazing thing to watch, and the video already has over 800,000 views since it was posted yesterday.

Enstone, a student at the University of Manchester majoring in physics, was attempting to identify the liquid for class, using a process known as spectrometry. When the liquid froze, boiled and vaporized, the student posted the video on YouTube and reddit to find out what had happened: he had found the triple point.

Reddit user Justin007isback helpfully explains:

“It’s called the ‘triple point’. It is where a substance is in all three forms (liquid, solid, gas) at the same time.”

According to Justin’s explanation, at the beginning of the video, the pressure is lowered by removing air from the glass. This causes the liquid to boil at a low temperature. As gas escapes the liquid, the liquid that is left cools down because of the kinetic energy that has left. The lower temperature causes the liquid to freeze.

So, some of the substance might be liquid, while at the same time some is gas and some is solid. The temperature and pressure must be kept at a precise point in order to allow the substance to switch between all three phases quickly. This temperature and pressure is called the triple point.

YouTube user Raresh Vlad Bunea commented, “It’s not often people outside a lab get to see what this looks like, because you need a vacuum pump and some chemistry kit to achieve it. But it is amazing to see a fluid freeze and bubble and look like still liquid all at the same time.”

Since many substances have a triple point, and the student did not record the temperature reached inside the glass, there has been raging debate over whether the clear substance might be water. You can view the science debate on reddit here.

The triple point of water is 0.01*C and 0.0060373 atm, which is not too hard to achieve with the correct, lab-grade equipment. Round glass flasks like this one are often designed to withstand low temperatures. Many comments are claiming that it is water, or most likely water, for this reason.

Still, I wouldn’t drink it without knowing for sure. Haven’t you heard the H2SO4 joke?

Little Timmy took a drink,
But he will drink no more,
For what he thought was H2O,
Was H2SO4.

Though, I suppose if it was at the triple point, it would be difficult for Timmy to drink.

Interested in more viral YouTube videos? Try Violinist Lindesey Stirling Goes Viral.

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