July 10: Nikola Tesla born, Onnes liquefies helium, Scopes monkey trial starts

Nikola Tesla is born

Serbian-American electric engineer, inventor and researcher Nikola Tesla was born on 10 July 1856. He is best known for his design and development work on AC (alternating current) electricity supply systems, and designing the Tesla Coil – an electrical resonant transformer circuit used to produce high-voltage, low-current, high frequency alternating-current electricity. His work on AC current famously pitted him against DC current proponent Thomas Edison (his former boss).

Tesla’s influence and inventions have led to several things named after him including an oscillator, a turbine, a crater on the Moon, and the motor vehicle company we know of today.

Nikola tesla
Credit: Martin van Meytes


Helium liquefied

On 10 July 1908 Dutch physicist Kamerlingh Onnes became the first person to make helium liquid at a temperature of 4.2 K (about -269°C). Onnes received the 1913 Nobel Prize in Physics for his low temperature work. Today liquid helium can be used as a cryogenic refrigerant and is produced commercially for use in superconducting magnets like those found in in magnetic resonance imaging (MRI) machines.

Scopes monkey trial

On 10 July 1925, the Scopes monkey trial began in Dayton, Tennessee, USA. A local schoolteacher, John Scopes, was prosecuted for teaching the theory of evolution in school, prohibited under the state’s Butler Act.

John scopes
Photograph of John Scopes by Watson Davis


Towering US legal and political figures William Jennings Bryan (for the prosecution) and Clarence Darrow (defending Scopes) helped attract attention to the trial. Scopes was convicted and fined $100.

The law was repealed on 17 May 1967.

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