As we wrap up our chemistry unit, we have been exploring chemical reactions. As much as I would love the whole class to walk away with the ability do discuss endothermic reactions, precipitate formation, and the conservation of mass, none of those are what I really care about the big “takeaway” being. The biggest concept I hope they walk away from our science unit is an understanding of the Scientific Method, and how we test ideas.
After introducing the concept of a chemical reaction though a candle demo, we started exploring a more common example - baking soda and vinegar.
Using our observations, we discussed what was happening during the reaction. We identified the reactant and products and talked about the fact that there should be the same number of atoms of each type on the product side and the reactant side.
From there, we reviewed the scientific method and the steps of an experiment. Using that structure, students used guided inquiry to explore a testable question about the baking soda and vinegar reaction. To investigate the question “What ratio of materials creates the best reaction?” students chose two different amounts of each material. This allowed them to test four different ratios of materials.
Following the procedure, gathered their materials and followed the procedure for mixing the materials.
Students recorded what happened through both quantitative (measurable), and qualitative (observational) methods.
Using their data and observations, they wrote conclusions about which ratio they thought created the best reaction. As we discussed, students thought about other great testable questions we could have extended to, including “what if we warmed up the vinegar?” and “does the shape of the container matter?”
After the experiment was done, we continued to solidify our understanding of conservation of mass by building the reaction in skittles. We picked a different colors to represent each type of atom. From there, they built and recorded the molecules in the reactants and then rearranged them into the products.
Would I like them to be able to identify the reactants and products in a reaction? Definitely! But in the long run, knowing how to learn though testing a hypothesis is more important.