Use visuals and video as part of a lesson opening to help students access new content in a unit or lesson. This allows them to preview the topic you are teaching and gives them an image to hold onto throughout the lesson.
In this 4th grade social studies class the students are reading Chains by Laurie Halse Anderson. To preview a slave auction, the Do Now asks students to describe this image in their quick write journals.
Here a teacher is beginning a science unit about osmosis. This video gives students a preview of the content and will support their later reading on the topic.