In 1974 the Christmas Lecturer thought he had discovered something that violated the first law of thermodynamics.
Eric Laithwaite was a British electrical engineer and presenter of the 1974 CHRISTMAS LECTURES who sparked a controversial debate with his unconventional views on the behaviour of gyroscopes.
He was convinced that the counterintuitive behaviour of gyroscopes wasn't possible according to the accepted laws of physics. His colleagues did not share his belief. Read the full story, and the impact it had on Laithwaite's career, in this article from Professor of History of Science, Frank James.
Watch YouTuber Derek Muller show the particular demonstration that so baffled Laithwaite:
And then watch the infamous Lecture itself: