Example: My lifelong dream of making my fortune by cornering the lint market just didn't pan out.
Origin: Early prospectors panned for gold. They would swirl a mix of soil and water around the pan.
Because Gold is very dense, with a little skill the pan could be swirled at just the right speed to allow the gold to settle to the bottom of the pan, while the dirt and low-density particles would wash over the side. This would continue until there was nothing left but gravel -- and maybe a little speck of gold if it "panned out"!
