I use Starter Questions, or Warm-Ups each day to re-focus the students onto the topic. Our school is on a block schedule, and since I see them every other day, these question really help. My students record their answers in their notebook, so that they have them for review purposes. We then discuss and share answers.
This product contains 15 starter questions for use during a unit on geologic time and fossils - one question per power point slide, with the second slide showing a suggested answer.
Questions are written so that they will require a bit more from the students than just information recall. Thinking, analyzing, and researching will be required. It helps if enough of your students have a device to use so that they may research some of the answers if you have not introduced the topic yet.
I often use some of these questions before I have talked about the topic, and use some of them for review of the previous class discussion.