This activity is perfect for children in lower elementary classrooms as it is hands on and extremely visual. The materials are very easy to find and project is reusable as long as you have Alka-Seltzer tablets to spare. The concept behind how this demonstration works is a little complicated but the resource does a good job at explaining it. I think this activity can serve as a great introduction to the structure of molecules and their different properties of matter (oil vs. water). Observing how different materials interact with each other and being able to describe what is happening is a good foundation for the elementary students to be able to build on and perform their own experiments.