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Carboniferous Period – Geology

By |2019-02-28T09:47:59-07:00June 23rd, 2017|Geology|

Dragonfly When was the Carboniferous period? With the end of the Devonian period about 359 million years ago, the Carboniferous period got started. More about the Devonian Quick summary of geological eras All our geology articles What was the Earth like then? Most of the land on Earth was warm and swampy, which [...]

Calcium project – Chalk and lemon juice – Chemistry

By |2019-02-26T05:52:48-07:00June 1st, 2017|Chemistry|

Need chalk? Buy chalk Chalk has calcium in it Take a piece of regular white chalk, like for writing on a blackboard. Make sure the chalk is calcium carbonate like the kind in the picture. Some kinds of chalk are made of plaster of paris. You don't want those. What is calcium? More [...]

Calcium – Atoms and Chemistry

By |2019-02-26T05:37:02-07:00June 1st, 2017|Biology, 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 iron, calcium is one kind of atom it makes along the way. More about stars And about atoms All our chemistry articles What's [...]