A vortex tube is a mechanical device that separates compressed gas into cold and hot streams. It has no mechanical parts and is also known as the Ranque-Hilsch vortex tube.

A tornado is a vortex and may also contain vortices. A vortex is a rotating body of liquid or gass. In a tornado, the vortex is made visible by condensation or dust and debris. It may look like a cone, tapering appendage, or column attatched to the clouds, or may take the appearance of a tube or swirling mass of dust.

Karl Elser has written:

'The behaviour of various gases and the separation of mixtures of gases in a vortex tube'

No. A tornado is defined as a violently rotating column of air extending from the base of a thunderstorm to the ground. The vortex in a tornado tube may rotate, but it meets none of the other criteria.

No. Vortex is a noun.