Ordovician Period – limestone and liverwort
The Ordovician period saw the evolution of the octopus At the end of the Cambrian period, about 488 million years ago, most of the plants and animals living on Earth [...]
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06, 2017
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06, 2017
What happened in the Archaean Eon?
Archaean Eon: A volcano erupts out of the water The beginning of the Archaean Eon After the end of the Hadean Eon is the beginning of the Archaean Eon. That's about [...]
1
06, 2017
Calcium – Atoms and Chemistry
Chalk cliff (made of calcium atoms) in Cottonwood Canyon, Pueblo, Colorado What is calcium? When a star is on the way to converting all of its carbon and oxygen atoms into [...]
25
05, 2017
What is marble? History of Art
What is marble? A Cycladic figurine from Ancient Greece in marble, once realistically painted. What is marble made out of? Marble is metamorphic limestone . That is, marble is a metamorphic rock [...]
25
05, 2017
What is limestone? History of Art
A block of limestone Starting with seashells Limestone is a kind of sedimentary stone that is very common all over the world. This kind of stone forms out of the shells of [...]
25
05, 2017
What is fresco painting? History of Art
Fresco painting from Thera, Greece (about 1600 BC) Why are they called frescos? Fresco is the Italian word for "fresh", and that's because painters do fresco painting on fresh, wet plaster [...]
25
05, 2017
What is tufa? History of Architecture
A block of tufa from Caere with an Etruscan inscription on it. Tufa (some people call it "tuff") is a kind of limestone that is very common in Italy. Tufa [...]
25
05, 2017
What is travertine? History of Architecture
Is travertine marble? No. The travertine is the white stone in between the bricks (This is from the Colosseum in Rome) Is travertine marble? Travertine is a kind of sedimentary [...]
24
05, 2017
Why do people plaster walls? History of Architecture
A bit of plaster left on the wall of a Punic house from Carthage People used plaster to cover the bare stone or mudbrick on the walls of houses, both [...]
