Making Lava lamps for Science

Year Five may have a few keen future scientists.  As part of our study of the properties of materials we conducted an experiment observing the different states of matter:  Solid, liquid and gas.  Creating a lava lamp using oil, water, food dye and alka seltzer contains two liquids, a solid and a gas all at the same time!  It also has two immiscible liquids (liquids that don't mix.)