Chapter Seven — Elemental Matters
A Short History of Nearly Everything – by Bill Bryson
Chapter 7 – Elemental Matters
- Brownian motion, which established the active nature of molecules, was discovered not by a chemist but by a Scottish botanist, Robert Brown. What Brown noticed, in 1827, was that tiny grains of pollen suspended in water remained indefinitely in motion no matter how long he gave the grains to settle. The cause of this perpetual motion – namely the actions of invisible molecules – was long a mystery.
- In 1811 an Italian, Lorenzo Avogadro, made a discovery that would prove highly significant in the long term – namely, that two equal volumes of gases of any type, if kept at the same pressure and temperature, will contain identical numbers of molecules. This fact became known as Avogadro’s principle.
- Using Avogadro’s mathematics, chemists were eventually able to work out, for instance, that a typical atom had a diameter of 0.00000008 centimeters.
- Atomic weight is the number of protons plus the number of neutrons in a given element. It should not be confused with the atomic number, which is the number of protons in the nucleus of a particular element.
- Robert E. Krebs made the following statement: “Without a doubt, the Periodic Table of the Chemical Elements is the most elegant organizational chart ever devised.” The chart is primarily the work of Dmitri Mendeleyev.
- Today, we have 120 or so known elements, with 92 occurring naturally and a couple dozen more that have been created in laboratories.
- Marie Curie is the only person ever to win a Nobel Prize in both chemistry and physics.
- Radiation is so pernicious and long-lasting that even now Marie Curie’s papers and cookbooks from the 1890’s are too dangerous to handle. Her laboratory books are kept in lead-lined boxes, and those who wish to see them must don protective clothing.
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