Summary Smash wintergreen lifesavers in a dark space to show luminescence from mechanical cleavage (triboluminescence). Science content Chemistry: Atoms, Molecules (3-7) Chemistry: Chemical Changes (2, 7) Physics: Light and Sound (1) Physics: Energy forms, Conservation of Energy (1, 3, 4, 5) Science competencies (+ questioning + manipulation + others that are in every activity) Evaluating: inferring (3 up) Lessons activity is in Light from Chemistry Materials dark room e.g. behind curtains on the school stage wintergreen lifesavers (must contain methyl salicylate) hammer dark cloth clear piece of plexi, or other hard plastic tray to contain flying lifesaver pieces Procedure This activity needs quite a dark area, so give students a while to get their eyes adjusted to the dark first. Place a wintergreen lifesaver on the cloth under the piece of plexi. Smash the plexi with a hammer. As the candy gets broken into small pieces, flashes of blue light are seen in different places under the plexi. Young student explanation: when you hit the candy you put in energy. The energy comes out again as light. Older student explanation: As you hit the candy you separate charged particles. As electricity flows between them it excites the nitrogen in the air. The excited nitrogen re-emits the energy as light - mostly UV but some blue. This happens with regular sugar, but the light emitted is mostly UV so not so visible. The wintergreen flavour amplifies the light - methyl salicylate is a fluorescent molecule: it absorbs the UV emitted by the nitrogen and re-emits blue light, so making the light given off more in the visible range where we can see it. Notes Apparently you can also see the sparks by crushing the wintergreens with your teeth with your mouth partially open. Grades taught Gr 1 Gr 2 Gr 3 Gr 4
