Tin tears

Tin cries. Not tears, but when tin is bent it elicits a peculiar sound called by metallurgists a "tin cry". Indium also lets out a scream when deformed, as Michael Cassidy pointed out in an earlier comment.

You are hearing the sound made by a phase transition, a change in the structure of the metal at the atomic level. Indium in its crystalline form is tetragonal, when bent, the mechanical stress induces "twinning" in which sections of the crystal become mirror images of adjacent planes. Twinning plays a role in mechanical failure of metals subject to stress, the research literature goes back roughly a century.

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Listen to a recording of indium "screaming" made by Theodore Gray at the WGBH studios. It's an unnerving sound, more like a crackling than a scream.

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The photo is courtesy of David Hammon in the physics department at the University of Vermont.