This article describes a project in which students investigate the question: What dihedral angles between pairs of mirrors in a kaleidoscope result in perfectly symmetric images? The unit culminates with students building their own kaleidoscopes. This content aligns with parts of the Common Core's standards for fifth grade (classify…

Infinity and infinitely small numbers pique the curiosity of middle school students. From a very young age, many students are intrigued, interested, and even fascinated by extremely large or extremely small numbers or quantities. This article describes an activity that takes this curiosity about infinity into the domain of adding the numbers of an…

This article describes a hands-on activity in which students convert decimals to fractions, measure, make scale drawings, use algebraic formulas, and use visualization to construct a three-dimensional physical model of a portion of the seafloor. In the process, they learn about sound, speed, and ocean exploration. (Contains 2 figures.)