The class did a density lab where they change the density of water by adding different amounts of salt. The hard part is to decant the solution so the different densities don’t mix. We used food coloring to show each different density layer. The bottom layer has 2.5 teaspoons of salt. The middle layer has 1 teaspoon of salt, and the top layer has no salt, just yellow food coloring. We used 100ml of water for each layer. Put a piece of cardboard on top of the red layer to decant. The class did a great job.