• Asignatura: Inglés
  • Autor: lemjo
  • hace 9 años

un tema científico en ingles que dure 5 minutos

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Respuesta dada por: TriviñoJosselyn
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Did the Great Pyramids’ builders use concrete?

CAMBRIDGE, Massachusetts — It is a theory that gives indigestion to mainstream archaeologists. Namely, that some of the immense blocks of the Great Pyramids of Egypt might have been cast from synthetic material – the world’s first concrete – not just carved whole from quarries and lugged into place by armies of toilers.

Such an innovation would have saved millions of man-hours of grunting and heaving in construction of the enigmatic edifices on the Giza Plateau.

“It could be they used less sweat and more smarts,” said Linn Hobbs, professor of materials science at the Massachusetts Institute of Technology.

“Maybe the ancient Egyptians didn’t just leave us mysterious monuments and mummies. Maybe they invented concrete 2,000 years before the Romans started using it in their structures.”

That is a notion that would dramatically change engineering history.



TriviñoJosselyn: It has long been believed that the Romans were the first to employ structural concrete in a big way, although the technology may have come from the Greeks.

A handful of determined materials scientists are carrying out experiments with crushed limestone and natural binding chemicals – materials that would have been readily available to ancient Egyptians – designed to show that blocks on the upper reaches of the pyramids may have been cast in place from a slurry poured into wooden molds.
TriviñoJosselyn: At MIT, Hobbs and two colleagues teach a course called Materials in Human Experience. Over the years, undergraduates in the program have recreated from scratch such artifacts as samurai swords, tinkling Meso-American bells and even a swaying 60-foot, or 20-meter, plant-fiber suspension bridge like those built by the Incas.
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