Coin Appears When Water Is Added

The coin appears. Ask students to predict what will happen. Position viewer so rim hides coin, then add water without moving viewer. Key idea: Light bends at the water-air boundary, changing the apparent position. Ask: Did the coin move? Safety and cleanup: Use plastic cup. https://www.siyavula.com/read/za/natural-sciences/grade-8/visible-light/12-visible-light?id=toc-id-4