Tin cry Tin cry A tin cry is the characteristic sound heard when a bar of tin is bent. Variously described as a "screaming" or "crackling" sound, the effect is caused by the crystal twinning in the metal. 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. The tin cry is often demonstrated as a simple science experiment. The bar of tin will "cry" repeatedly when bent until it breaks. The experiment can then be recycled by melting and
Gift Gift A gift or a present is an item given to someone without the expectation of payment or anything in return. An item is not a gift if that item is already owned by the one to whom it is given. Although gift-giving might involve an expectation of reciprocity, a gift is meant to be free. In many countries, the act of mutually exchanging money, goods, etc. may sustain social relations and contribute to social cohesion. Economists have elaborated the economics of gift-giving into the notion of a gift economy. By extension the term "gift" can refer to any item