GlobalNuclearNews

Nuclear History archive — page 18

A glowing vintage glass discharge tube next to a softly lit fluorescent screen on a bright background
Atoms & the Discovery of Radiation

Röntgen Discovers X-rays (1895)

In November 1895 Wilhelm Röntgen noticed a screen glowing beside a covered discharge tube, spent about seven weeks testing the invisible rays, and published the discovery of X-rays that swept the world in 1896.

A glowing glass Crookes tube with a violet beam leaving the cathode, a metal cross in the middle and the cross's dark shadow on the apple-green glowing far end
Atoms & the Discovery of Radiation

Particle or Wave? Cathode Rays from Faraday to the Crookes Tube

From Faraday's dark space in 1838 to Crookes's "radiant matter" lecture in 1879 and Perrin's negative-charge measurement in 1895, cathode rays split physicists into particle and wave camps and built the vacuum tools behind X-rays and the electron.

A grid of blue, teal and amber glass tiles with three glowing empty squares, one golden tile hovering above a gap
Atoms & the Discovery of Radiation

Mendeleev's Periodic Table and Its Blanks (1869)

Mendeleev's 1869 table ordered 63 elements by atomic weight and left gaps whose predicted occupants, gallium, scandium and germanium, were found by 1886.

A polished brass balance scale with a small pearly sphere on the raised pan and a larger sphere on the lower pan, against a bright pale-blue background
Atoms & the Discovery of Radiation

Weighing the Invisible — Dalton's Atomic Theory (1808)

Dalton's 1808 atomic theory gave every element an atom with a characteristic weight and explained the law of multiple proportions, even though his rule of greatest simplicity made water HO and oxygen 7 instead of 16.

A rough block of white marble on a sunlit surface, with clear glass beads breaking away from it and shrinking into fine sparkling grains against a bright blue sky
Atoms & the Discovery of Radiation

Ancient Atomism: Democritus, Epicurus and the Uncuttable Atom

Democritus and Epicurus imagined uncuttable atoms in a void; Lucretius's poem carried the idea, a 1417 rediscovery and Pierre Gassendi revived it, and modern physics kept the name while splitting the atom.