Online learning stimulates thought about a "balanced diet" between online tasks and practical 'making tasks' or at least, pen & paper (NO computer) work for mathematics and some asynchronous elements (I mark previous class's work during 6th to 25th minute of next class): 

• First 5mins I explain task and remind where the necessary resources are. 
• 20mins of lesson students work on a pre-defined task (posted in Managebac, Google Classrooms/Docs etc. i.e. online!). I get on and mark/review work set to class that just left.
• 5mins After 20mins, students 'share' their work. A number of ways of doing this: a photo of their paper working out, working out in Onenote classroom, all students show their work using the 'video' teams/hangout etc functionality.
• 5-10mins : I go over, live (Teams, Hangouts, Zoom etc.) any common questions/any common misunderstandings. 
• Next 20mins - I set the task (take 5mins to explain task), students work, I look through their work from previous 20mins.
• Last 5mins - students upload pictures etc. of their work which I will look through & prepare feedback for them in next lesson, using 20minutes of my next lesson (whilst the next class works on their practicaly/making activity).

This activity:  Prism Volumes for example could extend over 1 or 2 lessons. From experience I recommend sand or sugar or rice etc. rather than water!!