Just because a flipped classroom is called a flipped classroom doesn't mean that there can't be some review for the beginning portion of class time. This means that the issue of students not being prepared can be resolved by 5~10 minutes in the beginning of class. The rest they can pick up from their peers who have done the work through group work, discussions or class collaboration.

Most of the flipped classroom materials are not very long (the well-done materials are usually somewhere between 5~7minutes). This means they can watch the video while they take the bus to work, during their lunch time at school, or a quick 10 minutes after school on a school computer if they do not have access to devices.

If a student goes into class with some notion of what is going to be covered in class that day, I think that is a plus for their learning.

A flipped classroom is a method that can be implemented by using these tools -- a simple way to check and hold students accountable for looking at the material beforehand is to administer a pre-class quiz that the students have to take before class starts. This way, even if the students don't look at the video, the teacher will know the important key points to go over in the first 5-10 minutes of class and can spend the rest of the class time to do group work, discussions, debates, etc.

Flipper learning is a great teaching method to use for classes that are application oriented. For example, my college physics class utilized a flipped classroom. The students were responsible for watching a video that discussed the basic conceptual understandings of a certain topic and then to take a pre-class quiz before class time. The instructor would then spend 10~15 minutes going over the topics and the students would then use the rest of the class time to solve problems by discussing with peers, do lab work and take a short quiz at the end of the class.

The pre-class quiz was a tool to make sure that students were held responsible for preparing for the class but it also helped the instructor be aware of what students did not understand in the pre-class video. Then, in the first 10~15 minutes, the instructor would go over the pre-quiz and point out questions that majority of students got incorrect. This was a great way to measure pre-existing knowledge and level of understanding before class even started. Teachers who have access to Google Classroom can definitely implement this method; it is easy to create a quiz using Google forms or Quizlet to gather data before class starts.

I also believe that all too often in a class like math or physics, students do not learn problem solving if the problem-solving is done for them. What I mean to say is in teaching methods like direct instruction, the students learn from the teacher but they rarely are forced to generate their own thoughts. In a flipped classroom, if implemented well, the students would have to discuss with their peers to try to solve the problem because the teacher will not solve it for them. I think it is a great way for students to be active participants in their learning.