By the end of eighth grade, students will develop an understanding of properties and changes of properties in matter. Students predict what will happen when they mix baking soda with water and with vinegar. Students build models of an element of their choice using materials such as toothpicks, wire, string, and clay or plastic foam balls. They may wish to use three different colors to distinguish the neutrons, protons, and electrons. Have students describe and display their models.
Students pass an electric current through a mixture of baking soda and water.
When the circuit is closed, water is split into hydrogen and oxygen, and bubbles form. When the circuit is open, the reaction stops and no bubbles are produced. Students examine properties of solid elements, classify them according to their properties, and use those properties to classify other objects.