Other Density Demos:
I attached a Word document that is a template for a guided lab report that you feel free to modify and use.
Other Ideas and Resources:
These are just some ideas and alternate extensions.
Some additional references will many different versions of this same idea:
DENSITY: SALTWATER COLUMN LAB TEACHER PREPARATION
Explains a different way to prepare solutions and some "discussion" questions as a worksheet for students
Written from the standpoint of ocean science for elementary school. Contains a lot of "teacher lingo" (e.g. key concepts, big idea, objectives, etc.)
GEMS: Discovering Density book
This book costs $18, but I think is where I first saw the idea for this lab. The handouts are free online in Spanish. So that might make this a cool activity to do with students learning Spanish too!
Steve Spangler 7-Layer Density Column
This link provides a video showing a different density experiment with different types of liquids to see how their relative densities are different. They do use the word "heavier" instead of density. He uses a slightly different way of layering.
NOAA Lesson Plan: Hot, Cold, Fresh and Salty
Another Earth Science/Oceans connection. This lesson plan gives ideas about having students compare hot and cold water and fresh and salty water. These are extensions that would be great to add to a simpler lesson like the one I posted.