Much fuss has been made of this, with some claiming to have "invented" it and writing books, giving lecture tours and making money from what is really an old idea.
What is flipped teaching?
Traditionally, students would meet something in class, explore it, even do some exercises and then for homework review, develop, reinforce etc. That is, the student sees the material first in class under guidance and then works on it at home, alone. Flipped teaching is when the student sees the material first at home, perhaps alone, and explores it, perhaps with some exercises to assist, and then secondly takes it to class to work with it under guidance.
I used this method in the 1980s with High School students. I was teaching literature and, for example, I would give students an essay by Professor X and ask them to read it, paraphrase its arguments and then take a position for or against those arguments, all the while referring to the essay and the text we were studying. Or I would give them several articles from newspapers and magazines and ask them to find the similarities. Incidentally, the best results came from seemingly unrelated topics which would send the students looking at style and perspective
I don't know where this approach originated, if I "invented" it or acquired it from my teacher preparation classes, or from my experienced colleagues. In the 1990s, I learnt it was used routinely at business schools and was sometimes called "cold calling" or the "Harvard method". Students would be given case studies to read and analyze prior to the class, and one or more would then be chosen at random to present to the class, or to lead a group, before the professor stepped in with his/her perspectives or even the real point of the reading.
The only change in the noughties has been the advent of internet, broadband and HD streaming so that students can watch podcasts or videos which to me, is no different from the reading of the eighties and nineties. Flipped teaching is just a new name for an old approach.