[exarch]

The (scientist approved) test for determining basic matter phases is very rudimentary. Put the object/quantity in question in a can. Does it fill the whole space of the can, no matter what size can you use? Then it's a gas. Does it fill just the bottom of the can? Then it's a liquid. Does it instead retain its shape? Then it's a solid.

[knodi123]

The urban legend says that it's like pitch; if you put it in the can, it will slowly fill the bottom of the can, but it will take many centuries since it flows so slowly.

This is not true, but it means your test would not convince anybody of anything.

[exarch]

It should be convincing, because the test specifies a time limit in the range of a couple of minutes.