basalt

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26 06, 2017

What causes volcanoes? Geology

By |2018-04-21T11:56:42-07:00June 26th, 2017|Geology|0 Comments

Volcano erupting Volcanoes are places where the plates of the Earth's surface have cracks in them, so that the very hot melted rocks that are under the tectonic plates bubble up to the surface. We call the hot melted rocks magma. The magma is under a lot of pressure inside the Earth's plates, [...]

26 06, 2017

What are igneous rocks? Volcanic stone

By |2019-09-10T05:42:47-07:00June 26th, 2017|Geology|0 Comments

Igneous rocks: Obsidian tools What does "igneous" mean? Igneous means "fiery", and igneous rocks are rocks that were made by heating them up in a fire. Usually that fire is the big fire inside the earth, under the earth's crust. The first scientist who identified this kind of rock was ibn Sina. He [...]

25 06, 2017

Feldspar rock – a kind of igneous rock

By |2019-06-07T19:17:22-07:00June 25th, 2017|Geology|0 Comments

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 [...]

25 06, 2017

What is basalt? Igneous rock

By |2019-02-10T14:53:51-07:00June 25th, 2017|Geology|0 Comments

Where does basalt come from? Basalt is a fine-grained, hard rock that forms when bits of lava shoot out of volcanoes, so it's one kind of igneous rock. Igneous rocks Volcanoes All our geology articles What is basalt made of? Early Stone Age basalt choppers from Olduvai Gorge (Tanzania) When the lava cools [...]

12 06, 2017

Ancient Economy – Simple economic history

By |2018-04-19T11:10:59-07:00June 12th, 2017|Economy|0 Comments

Ancient economy: a bone sickle - the flint teeth are missing now Trade or self-sufficiency? Even today experts don't really understand how economics works. Historians also disagree about how economics worked in antiquity and in the middle ages. Some historians think that long ago most people were self-sufficient. They ate and wore mostly [...]