When learning about mixtures, elements and compounds, students can begin to understand the concepts by learning to identify what elements make up common objects. Bring in objects that students would regularly find in the classroom and at home and explain what elements they contain, such as graphite in a pencil, aluminum in a can, zinc in a penny and fluorine compounds in toothpaste. After this activity, begin to teach students about elements from the periodic table by having them color in their own periodic table or create a matching card where students list the element name on one card and the symbol or characteristics on another.
A mixture is a combination of substance where no chemical reaction has occurred. Students can practice separating mixtures to help learn about this concept. HMH School Publishers offers an online mixtures lab that teachers can use in the classroom to teach students about how to separate mixtures. Students receive a variety of mixtures and must devise a plan to separate the components of the mixture and choose the appropriate tools to separate them. Add a real-life aspect by having students solve a problem such as how to remove oil from water after an oil spill.
Explain to students that when elements combine, they form compounds. Using the periodic table, provide students with formulas for some common compounds such as baking soda, sugar and rubbing alcohol and ask students to determine which elements are found in each compound. Using different-colored gumdrops and toothpicks, have students practice making visual models of chemical compounds. Assign a different element to each color of compound and provide formulas that use those elements, then have students represent the formulas by using toothpicks to stick the gumdrops together.
Using their knowledge of elements, compounds and mixtures students can complete activities that require them to distinguish between the three. FOSS, a science curriculum organization, offers an online junkyard analysis game where students use a bulldozer to pick up items in a junkyard and determine whether they are an element, compound or mixture. A similar game can be played in the classroom where the teacher brings in common items that are made up of elements, compounds and mixtures such as vegetable soup, copper wire, a helium-filled balloon, breakfast cereal, dry ice, or a household cleaner. Play a game by calling on students to correctly identify whether the items are an element, compound or mixture.