How Many Changes Can You See?
Close observation of this system, and its subsequent motion, can lead to a great discussion of a myriad of science concepts. At the start, differences in texture (feel), color, smell and viscosity (thickness) of the substances can be noted. Identifying each substance as a solid, liquid, or gas can also be helpful as students process the similarities and differences of each state of matter.
After pouring one liquid on top of the other, the fact that one liquid is heavier than the other can be used to discuss density differences. The observation that the liquids are insoluble in each other can also lead to some excellent discussions in with respect to mixing, dissolving, and dispersing. As tiny pieces of Alka-Seltzer are added, the system is quickly propelled into a fast moving and quickly changing arena. As students observe and describe these changes, they can infer whether each represents a physical or chemical change.
Key Concepts: matter, mixtures, viscosity,density, solids, liquids, gases, chemical and physical changes.
