In this demonstration, learners compare and contrast regular water ice to dry ice (frozen carbon dioxide). Both samples are placed in a solution of acid-base indicator. The regular ice floats and the acid-base indicator does not change color; the dry ice sinks and the acid-base indicator changes color to show an acid solution has formed. This demonstration is part of a set of demonstrations and activities that can be used together for a larger lesson. Resource contains vocabulary definitions and suggestions for assessment, extensions, and scaling for different levels of learners.