Let students hunt for the signs of chemical change with their senses and bodies.
Sign-spotting with senses
Before the bicarb-and-vinegar reaction, give each group a "detective checklist" of the four signs (gas, colour change, heat/light, new material). As they run the reaction, they physically check off each sign they detect — feeling the cup for temperature change, watching for bubbles, listening to the fizz. Engaging multiple senses makes "a new substance was made" concrete.
Sorting on the move
Run the reversible/irreversible sort as a physical line-up. Students hold a change card and arrange themselves along a line from "easily reversible" to "completely irreversible", then justify their position to a neighbour. Re-sorting their bodies makes the spectrum tangible.