I found something interesting when I looked through my old copy of Cosmos by Carl Sagan. It was about classical Greek science. As strange as it may seem, at the time, many philosophers thought that air did not exist. It was just space. I am unsure how they explained wind, but they must have had some confabulation to make the wind fit into their worldview.
But the philosopher Empedocles came up with an easy demonstration that air was something, rather than nothing. He used a clepsydra, or water clock to prove it. The water dripped down at a steady rate, and was replaced by air at the top. But if air is not allowed to enter the top, the water will not drip. You can see the same phenomenon if you suck liquid into a straw, then close off the top of the straw, the fluid will not drip out. If the air was nothing, then this could not happen.
There are, all around us, many simple ways to test scientific hypotheses. When I wrote my book, Scientifically Thinking (see my website), I had not thought of this particular example. But you can read about lots of others in my book. Science is just, as Huxley said, organized common sense.