This activity is about classification of matter into pure substances and mixtures. It provides background information for the interactive activity below.
Among other things, students learn that solutions are not always liquid: homogeneous mixtures can also take gaseous or solid forms. (In the case of a solid solution, like a metal alloy, the different chemicals typically become mixed in the liquid phase and later harden into a solid.)
First show the diagram’s various stages that show how different categories of matter fit into one another. In this diagram, more specific categories are nested inside of more general ones.
Pretty much all the materials around us, and even in us, fit into one of two categories:
- Pure Substances (also called chemicals)
- Mixtures (combine multiple chemicals with chemcial reaction)
Within pure substances category there are:
- Elemental Substances (made of just one kind of atom)
- Compounds (combine multiple atoms in definite proportions)
Within the mixture category there are:
- Homogeneous Mixtures (also called "solutions")
- Heterogeneous Mixtures (unevenly mixed)