It worked for a while. How do I know? Because in class, more kids would take the initiative to come to me with questions regarding understanding rather than procedure. Because kids were getting group practice on sophisticated (more or less) questions done in class. Because I could see on thatquiz that students were doing their assignments and I loved seeing what was going well and needed re-teaching.
Then it didn't work anymore. Maybe it was in part because I was gone for a week and lost the connection with the class somehow. Students also say watching youtube videos was good (because you can replay) but also bad because you couldn't interact with the teacher to ask questions, etc. Of course, it's a much less social type of learning, and losing the social side can be hugely demotivational. The thatquiz homeworks, while done by many students, were sometimes done in something like 2 seconds per question - indicating that just maybe the students were copying other students' answers or in other ways avoiding actually thinking about the exercises.
The test results were horrible. We had a wonderful constructive chat afterwards, with the class unanimously agreeing to go back to the "old way", with going over new content in class and independent practice/review at home.
Even though it's disappointing that the flipped classroom strategy didn't work, I'm happy we tried it. It's this kind of experimentation that makes teaching fun, and the only way to eventually find more effective teaching strategies. If we hadn't tried it, I would always have wondered if we were missing out on something spectacular. Also, the kids learned a lot from this. Many of them still want me to post videos and they use thatquiz for extra practice with direct feedback, strategies they learned from our flipped classroom experiment.
Afterwards, I talked at length about why we tried flipped classroom (to get more time for problem solving / exercises in class because the students were not doing them at home). We talked about homework and how much they were doing. Very little, it turns out, and is rather unsurprising. We talked about if they want to do homework (unanimous yes) and how I can support them in doing it. I proposed, and the kiddos agreed, to try Mimi's strategy. In short, we agreed that the students will do at least 12 exercises from the book every week, I will collect them and choose one exercise per student to mark and give feedback on the overall level of difficulty of the exercises the students have chosen to do. Students seem enthusiastic about this idea, and I'm excited to try out yet another homework strategy. :)