The Known is finite, the unknown infinite; intellectually we stand on an islet in the midst of an illimitable ocean of inexplicability. Our business in every generation is to reclaim a little more land.  -T.H. Huxley, 1887



This is a simple device. It is a 2 foot tube with a screen mesh around 1/4 of the way from the bottom. We heat the screen with a blow torch until it is red hot. When removed the hot air rises through the tube. This flow velocity causes an instability which creates an acoustic tone. It is a simple example of acoustic instability with heat release.