How did Nikola Tesla contribute to science?

In 1887, he constructed the initial brushless alternate-current induction motor. He demonstrated the brushless two-phase one-fifth horsepower (150 W) induction motor to the American Institute of Electrical Engineers (now IEEE) in 1888. Also in 1888, he developed the principles of his Tesla coil wich he patented it 1891.

In April 1887, Tesla began investigating what would later be called X-rays using his own devices as well as Crookes tubes. He did this by experimenting with high voltages and vacuum tubes. His technical publications indicate that he invented and developed a special single-electrode X-ray tube. Tesla's tubes differed from other X-ray tubes in that they had no target electrode.

At the 1893 World's Fair, the World Columbian Exposition, in Chicago, Illinois, celebrating the 400th anniversary of Christopher Columbus' first voyage to America, an international exposition was held, in which, for the first time, a building was devoted to electrical exhibits. It was a historic event and the beginning of a revolution as Tesla and Westinghouse introduced visitors to AC power by providing AC energy to illuminate the World Columbian Exposition. The public at large observed firsthand the qualities and abilities of AC power.

Some doubted that the system would generate enough electricity to power industry in Buffalo. Tesla was sure it would work, saying that Niagara Falls had the ability to power the entire eastern U.S. On November 16, 1896, the first transmission of electrical power between two cities was sent from Niagara Falls to industries in Buffalo from the first commercial two-phase power plants (known as hydroelectric generators) at the Edward Dean Adams Station. The hydroelectric generators were built by Westinghouse Electric Corporation from Tesla's AC system patent designs. Tesla's system designs alleviated the limitations of the previous DC methods. The nameplates on the generators bear Tesla's name. He also set the 60 hertz standard for North America. It took five years to complete the whole facility.

He was the genius that created:

Alternating-current power transmission

The Death Ray Machine

Fluorescent lights

Induction motor

Polyphase alternating-current system

Radio

Rotating magnetic field principle

Telephone repeater

Tesla coil transformer

Wireless communication