1900:
- Phonograph (Emile Berliner's gramophone): An improved version of the phonograph allowed for better sound recording and reproduction.
- Zeppelins (Count Ferdinand von Zeppelin): Early rigid airships capable of controlled flight.
1901:
- Vacuum cleaner: Invented by Hubert Cecil Booth, the first vacuum cleaner was powered by an electric motor.
1903:
- Wright brothers' first flight: Orville and Wilbur Wright achieved the first successful, controlled, sustained flight in a heavier-than-air craft.
1905:
- Theory of relativity: Albert Einstein proposed the special theory of relativity, revolutionizing our understanding of space, time, and gravity.
1906:
- Triode vacuum tube: Lee De Forest's invention made possible the amplification of electronic signals, essential for radio and telephony.
1908:
- Ford Model T: Henry Ford introduced the revolutionary mass-produced car, making automobiles more accessible.
1911:
- Superconductivity: Dutch physicist Heike Kamerlingh Onnes discovered that certain materials exhibited a complete disappearance of electrical resistance when cooled to very low temperatures.
1913:
- Diesel engine: Rudolf Diesel's invention offered greater efficiency in converting fuel into mechanical energy, becoming vital for transportation and industry.
1914:
- Panama Canal opens: Facilitating trade and reducing travel time between the Atlantic and Pacific oceans.
1915:
- X-ray crystallography: William Henry Bragg and William Lawrence Bragg used X-rays to determine the structure of crystals.
1918:
- Electronic amplifier: Lee De Forest and Harold Arnold expanded on the triode vacuum tube to create the first practical electronic amplifier.
1919:
- First transatlantic flight: British aviators John Alcock and Arthur Whitten Brown made the first non-stop transatlantic flight.
1920:
- Radio broadcasting: The first commercial radio stations began broadcasting, introducing entertainment and news to a wide audience.
These highlights illustrate some of the key inventions and discoveries that profoundly shaped technology, transportation, communication, and scientific understanding during the first two decades of the 20th century.