- In modern physics, the double-slit experiment demonstrates that light and matter can satisfy the seemingly incongruous classical definitions for both waves and particles. This ambiguity is considered evidence for the fundamentally probabilistic nature of quantum mechanics. This type of experiment was first performed by Thomas Young in 1801, as a demonstration of the wave behavior of visible light. In 1927, Davisson and Germer and, independently George Paget Thomson and his research student Alexander Reid demonstrated that electrons show the same behavior, which was later extended to atoms and molecules. Thomas Young’s experiment with light was part of classical physics long before the development of quantum mechanics and the concept of wave–particle duality. He believed it demonstrated that Christiaan Huygens’ wave theory of light was correct, and his experiment is sometimes referred to as Young’s experiment or Young’s slits.
- Russian Empire (Wikivoyage)
The Russian Empire (Российская Империя) was the largest contiguous country in modern times, and the predecessor of the Soviet Union and present-day Russia. Reaching its maximum size during the mid-19th century, it included much of east and central Europe (including Finland and Poland), all of Siberia, much of Central Asia, briefly Alaska and even Fort Ross as far south as present-day California, though the degree of actual control by the tsarist authorities usually declined quite notably going from west to east. It also had a few concessions in China. Throughout world history, only the Mongol Empire and the British Empire have possessed a larger land area than Imperial Russia.