One is that he observed when people were machining cannon barrels, a lot of heat was generated, and there was a lot of work done.

第一种说法说焦耳发现,制作加农炮筒时，会产生大量的热，同时这中间有大量的做功。

麻省理工公开课 - 热力学与动力学课程节选

He was the first generation to go to college, grew up in the farms, and as such, he was very skilled with machining.

他是家里面第一个大学生，出生在农场，他很精通机械。

麻省理工公开课 - 固态化学导论课程节选