Tin cry

Tin cry

Tin cry is the characteristic sound heard when a bar made of tin is bent. Variously described as a "screaming" or "crackling" sound, the effect is caused by the crystal twinning in the metal.[1] The sound is not particularly loud, despite terms like "crying" and "screaming". It is very noticeable when a hot-dip tin coated sheet metal is bent at high speed over rollers during processing.

Tin cry is often demonstrated using a simple science experiment. A bar of tin will "cry" repeatedly when bent until it breaks. The experiment can then be recycled by melting and recrystallizing the metal. The low melting point of tin, 231.9 °C (449.4 °F; 505.0 K), makes re-casting easy. Tin anneals at reasonably-low temperature as well, normalizing tin's microstructure of crystallites/grains.

Although the cry is most typical of tin, a similar effect occurs in other metals, such as niobium,[citation needed] indium,[2] zinc,[citation needed] cadmium,[3] gallium,[citation needed] and solid mercury.[4]

  1. ^ "Video of the demonstration". University of Cambridge. Archived from the original on 23 February 2014. Retrieved 15 February 2021.
  2. ^ "LibreTexts, Chemistry, Chemistry of Indium". 2 October 2013.
  3. ^ "LibreTexts, Chemistry, Chemistry of Cadmium". 2 October 2013.
  4. ^ Reeder, Cody (17 Mar 2015). Bending Solid Mercury: It Cries!. Retrieved 3 December 2021.