Clear Water Beads 'Vanish'

Invisible-looking beads appear on spoon. Ask students to predict what will happen. Show apparently empty water, then scoop hidden beads. Key idea: Similar refractive index reduces visible boundaries. Ask: How can something be there but hard to see? Safety and cleanup: Choking hazard; teacher-only sealed storage. https://www.aps.org/learning-resources/bendy-light