SC.8.P.8.9: Distinguish among mixtures (including solutions) and pure substances…

Kitchen Chemistry Grades 7–8

Fizzing, curdling and colour changes with things from the grocery store. Students gather evidence of new substances, weigh a reaction in a sealed bottle, and turn red cabbage into an acid detector.

• Is it a new substance? 50–60 min

  Teams run six quick kitchen changes, from dissolving sugar to curdling milk, and record properties before and after. They sort each change as physical or chemical using evidence, and find out why a single clue like bubbles or a colour change isn't proof on its own.

• Where does the mass go? 50–60 min

  Teams weigh baking soda and vinegar reacting in an open cup, then in a capped pop bottle. The open cup gets lighter and the capped bottle doesn't, until they open it. Students use atoms to explain why mass is never lost in a reaction, only let out.

• Can red cabbage tell acid from base? 50–60 min

  Students add purple cabbage juice to safe household liquids and watch it turn pink, purple, blue or green. They build a colour scale, sort the liquids into acids and bases, identify two mystery liquids, and watch an acid and a base cancel each other out.