Tag: Dmitri Mendeleev
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Scientific discoveries in dreams: Sleeping while the mind works
Edward TaborBethesda, Maryland, United States Some major scientific discoveries have been revealed in dreams during sleep. Since ancient times, Western culture has included a deep belief in the power of dreams to provide information. The Greek philosopher Heraclitus (c. 500 BC) spoke of how “even in their sleep men are at work.”1 The Roman emperor…
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The periodic table of the elements
In this system hydrogen is assigned the number one, lithium is three, carbon six, nitrogen seven, oxygen eight, etc. The elements are organized in rows or periods and columns or groups according to their atomic weight. The elements were discovered beginning in the 18th century when the Swedish chemist Carl Wilhelm Scheele discovered oxygen (1772),…