Chemical Engineering in Daily Life - Question 9 - Standard answers available

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This post was last edited by yjqin1 on 2015-8-20 at 19:23. Winters in the north are bleak and boring. In the 1960s and 1970s, apart from engaging in the fashionable practice of digging ditches in the fields and criticizing the rich, the corrupt, the reactionaries, and the right-wingers, adults would also gamble a little money. The children are even more bored; aside from watching those movies over and over again and pretending to fight just like in the movies, they engage in a form of gambling. Almost no learning needed*. One type of minor gambling game is called “throwing ingots”; its main tool is the so-called “tin ingot,” which is a metal disc that resembles a coin, but is thicker and has a larger diameter. The children have to try every means possible to collect the so-called tin, and then melt it in a small pot. Use another brick to carve out the shape of a \"tin ingot,\" pour the melted tin into it, and once it solidifies, it becomes a tin ingot. Back then, coal was used to do this task; the temperature wasn’t very high, especially in winter, and there was no good insulation either. The melting point of tin is 232 degrees, which is quite high. But I found that the tin had good fluidity and took a long time to solidify. May I ask, what are the chemical or industrial principles behind this?