The hot gases move fast as they leave the back of the rocket.

Indeed, some applications require contact between the material and the hot gas.

"The smoke and hot gas are going to kill our plants," he said.

So a fire is made out of matter, but it is like a hot gas.

He had breathed in some very hot gas and air.

This means that fusion only occurs within a very hot gas.

This is due to the buoyant force on the hot gas.

Fire isn't a substance at all, but a process involving hot gases.

Consider, as a thought experiment, dropping an amount of hot gas into a black hole.

There is a small earthquake and hot gas explodes into the lake.