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History of glass – Who invented glass?

By |2019-07-07T10:37:45-07:00September 5th, 2017|Ancient, Science, West Asia|

Obsidian: naturally occurring glass History of glass: Glass beads from Old Kingdom Egypt, about 2700-2500 BC People have been using naturally occurring glass since the Stone Age, when they wanted an especially sharp edge on a tool or an arrowhead. What is obsidian? Egyptian science African science All our ancient Egypt articles All Africa [...]

Mercury – Planets – Astronomy

By |2018-05-31T11:49:17-07:00August 18th, 2017|Physics|

Mercury from space Mercury is the closest planet to our Sun. At some parts of its orbit, Mercury is only about 46 million kilometers away from the sun. Because Mercury is so close to the sun, it is very hot there. It is so hot that all the carbon dioxide and oxygen has boiled away, and Mercury has very little [...]

Feldspar rock – a kind of igneous rock

By |2019-06-07T19:17:22-07:00June 25th, 2017|Geology|

A feldspar rock quarry in India Is feldspar rare? Feldspar is a very common igneous rock. More than half of the Earth's crust is made of feldspar. What are igneous rocks? All our geology articles What is feldspar made of? When molecules of aluminum, silica and oxygen get together with potassium, they combine [...]

What is silicon? Atoms, elements, chemistry

By |2018-04-24T14:46:23-07:00June 2nd, 2017|Chemistry|

Diagram of a silicon atom When a red giant star is getting older and runs out of helium fuel, it starts to convert the oxygen atoms in the star into silicon atoms. All silicon is made this way, inside a red giant star. Silicon is heavier than oxygen, because oxygen has only eight protons [...]