My daughter (while in 2nd grade) joined my class for bring your child to work day, and she worked with the 8th graders as they made models of geologic time. This activity was engaging for both age groups. Find the details for the activity here.
Disclaimer: Adding machine tape may be hard to find on short notice. Check online, or at office supply stores. I’ve seen versions that are done on toilet paper too, but it would be easiest to color and draw on the adding machine tape.