Hopefully some scientific researchers are trying to determine exactly how dangerous the coronavirus is to students before everyone tries to re-invent the wheel. In any case, if a teacher is doing direct instruction by a video link, there’s no reason why they shouldn’t record a carefully crafted lesson with graphics, imbedded video, and pauses for interaction, and just play the same one over and over. The teacher can answer questions on the message board while the students watch the lesson. Or the teacher could just download a professionally made video about the content from Youtube, and again answer questions while it plays or is paused. If students have to watch the lesson on a screen, it should be more than just some teacher blathering in their kitchen, because it can be. It should be good video.