Rijke Flame
A singing flame you play with your hand. Drag the glowing gauze down into the tube's lower half and it spontaneously breaks into a loud standing-wave tone — Rayleigh's thermoacoustic criterion made audible. Slide it up and the song dies. Drag the top handle to set the pipe's length and pitch.
Starts the sound. Drag the glowing gauze into the lower half to make it sing; drag the top handle to change pitch. Leave it idle and it plays itself.