The flipped classroom in its simplest form is swapping the lecture part of a traditional classroom instructional model from inside the classroom to outside the classroom; in order that more time can be made available inside the classroom for more personalised learning.

Flipped Classroom Image from: https://vimeo.com/70893101

In its most well known formulation - this involves the teacher creating instructional videos which the learners view outside the classroom for homework - they then do what was their homework (assignments, etc.) in class time where they can receive more personalised help. However as Jon Bergmann explains this is only one way in which a flipped classroom could take place. It doens't necessarily require videos and the key for him is answering the question - "What's the best use of your face-to-face class time?" For him as a Science teacher it was more time doing experiments and working on harder problems. For PE teachers he talked to - it was more time moving the body and less time explaining how the body should move. In my own experience it was to free up more time for investigative work in the maths classroom.

Other key lessons for Bergmann are that we must teach students how to view the videos (do the first few in the classroom and teach them how you want them to record notes) and also build in interactivity wherever possible.

Bergmann and Sams (2012) who are perhaps most famously associated with this practice no longer promote this particular model (which they call "Flipped Learning 101")  but rather promote what they call "Flipped Mastery Learning." This involves making all their videos for the entire course available at once so that students are able to move through the material at their own pace. 

While this practice is undoubtedly more efficient - and if applied well could free up enormous amounts of time in the classroom there is a key feature which requires further scrutiny.

This is the fact that no matter how well the time is spent in the classroom - the lecture has still been retained. That is, the instructional model is the same; essential learning takes place though transmission - from video to student - rather than knowledge being constructed by the learner or co-constructed by learner, peers and teacher. Kalantzis and Cope (2017) describe this as being a "didactic pedagogy... brought back to life." 

The challenge then perhaps in considering the flipped classroom is not only to make the best use of the time available in the classroom but also to look at whether alternative ways of knowledge construction can be utilised.

References:

Bergmann, J. and Sams, A. (2012). Flip your classroom: Reach every student in every class every day.

Cope, B. and Kalantzis, M. (2017) e-Learning Ecologies: Principles for New Learning and Assessment.