Formative assessment takes place in steps 3 and 7 of the activity. When students are asked about whether air has mass, Level 2 students, in particular, may not believe that air has mass or is made of atoms. They probably think of air as insubstantial—not a material like solids or liquids. Some Level 2 students and virtually all Level 3 students say that air has mass and is made of atoms, but they often fail to consider the mass of gases or the atoms and molecules in gases when they explain carbon transforming processes, like combustion or plant growth.
When students are asked questions about atoms in ethanol, most students will confirm that ethanol contains atoms, but many of them will not be able to apply the facts about atoms to the atoms in ethanol. For example, saying that the ethanol is “burned up” or “turned into energy” is in conflict with the first fact: Atoms last forever. When questioned about atoms in flames, students may have difficulty because in a flame we see both materials: glowing gases and white-hot particles of soot, which are made of atoms; and forms of energy, heat and light, which are not made of atoms.
Remember that these questions are particularly difficult and especially challenging for Level 2 students who are just learning to connect atomic models with macroscopic phenomena.