How to Model Chemical Reactions with Magnetic Whiteboard Blocks
Chemical reactions happen at a scale students cannot see. Atoms rearrange, electrons shift, and matter transforms, but all of it stays hidden behind symbols on a page. Students are asked to track substances at the macroscopic, particulate, and symbolic levels at the same time, which is a heavy cognitive lift. When a reaction like iron rusting is reduced to 4Fe + 3O₂ → 2Fe₂O₃, the meaning behind the coefficients and subscripts often gets lost.
The video above shows one way to model the reaction. A chemistry lesson with Switch-Its might progress like this.
Modeling rust with Switch-Its
Students can start by writing the macroscopic reaction (solid iron plus oxygen gas yields rust), then drop down to the particulate level by drawing Fe atoms and O₂ molecules with valence electrons on individual Switch-Its magnetic dry-erase blocks. From there, students rearrange the blocks to form Fe₂O₃ units, then count atoms to balance the equation as 4Fe + 3O₂ → 2Fe₂O₃.
Three scales, one reaction
Macroscopic labels sit on top, the symbolic formulas (Fe(s), O₂(g)) sit just below, and the particulate atoms sit at the bottom. Students see all three representations at once.
Valence electrons in plain sight
Students draw dots around each atom to show outer-shell electrons, then mark charges (Fe³⁺, O²⁻) to predict how the atoms will pair up. The bonding logic becomes visible.
Balancing as rearrangement
Once atoms are grouped into Fe₂O₃ units, students physically move blocks to match atom counts on both sides. Coefficients stop being a math trick and start being a count.
The result is an abstraction students can hold in their hands. Iron, oxygen, and rust stop being words on a page and become objects that connect, separate, and recombine, which is what chemical reactions actually are.