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Sensitive Flames

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  p-234

2025-11-20

519

Demonstration. - Select a piece of small gals tubing and draw it to a point in the Bunsen flame, leaving a fine opening. Connect the other end, by means of a rubber tube, to a gas supply, and if you have the right size of hole in the tube, and the right pressure of gas, which is generally greater than city gas mains supply, you will get a long line of flame, as in A (Fig.1), that is just on the point of flaring. Make any kind of a sharp sound, and the flame will at once drop down to the form of B, and will keep flaring in that form as long as the sound continues. A shrill whistle, the rattle of keys, or any hissing sound will produce the same effect, showing that this is a very sensitive form of flame. Does the rapid change in pressure at the mouth of the tube, caused by the waves of condensation and rarefaction due to the high pitch of these sounds, explain the action of the flame? Test this flame by giving a shrill whistle outside of the room when the door is closed.