is James Joule's birthday. Joule was the English physicist who helped formulate the first law of thermodynamics
. He showed heat energy and mechanical work were related and that energy of a system was conserved. He showed electrical energy and heat energy were interchangeable by relating the heat dissipated by a resistor to the electrical current passing though it. Later in life, he worked closely with William Thomson (Lord Kelvin) to establish the absolute temperature scale
. They also discovered the Joule-Kelvin effect where an expanding gas is cooled by the expansion.
Joule never attended a university and began many of his achievements from a home laboratory where he spent his time after his work running the family brewery. After the brewery was sold off, he spent the rest of his life pursuing his scientific hobby. He was a major contributor to the new scientific field of thermodynamics and was honored by naming the SI unit of energy, joule, after him. Find out what else occurred on this day in science history
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