In doing so, they develop the ability to recognize general patterns that tie ideas together-an ability that frees students from learning many individual facts.
Students discuss or demonstrate various ways to separate mixtures by physical means.
Demonstrate how to distinguish between mixtures and compounds. Demonstrate that elements in a chemical compound can be separated only by destroying the compound. Have students compare the conductivity of various substances in solution. This can lead to a discussion of the existence of ions. Students classify as elements, compounds, or mixtures common materials such as water, copper, lead, brass, naturally occurring metal ores, salt, sugar, chocolate chip cookies, coffee, tea, and iced tea.