Sand storm

• Autores: Julian Smith
• Localización: New scientist, ISSN 0262-4079, Nº. 3165, 2018, págs. 35-39
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Like stars, snowflakes and blades of grass, sand is one of those things that seems to be in infinite supply. It has been a symbol for quantities beyond counting since ancient times. When the biblical hero Joseph faces an impending famine in the book of Genesis he stored up grain in great abundance like the sand of the sea, until he stopped measuring it, for it was beyond measure. Think of sand and you probably picture the golden-brown stuff on the beach, which is largely made of silicon dioxide. Yet sand is defined not by its composition, but by the size of its grains, which are smaller than gravel and larger than silt. Roughly speaking, that means between 2 and 0.06 millimetres. The different kinds suit different applications, but there is one need that dwarfs all others. Between 60% and 75% of the sand we mine goes to sate our hunger for concrete.