Real-world investigations can move students in the middle grades from their earlier, informal understanding of measurement to the abstract, sophisticated understanding they will need in high school. This book provides hands-on activities that build important strategies and concepts. Students learn about accuracy and estimation and they develop formulas for the perimeter, area and volume of two-and three-dimensional figures. In exploring proportionality, scaling and similarity, they build a scale model of a room and make a pi ruler to help gauge the age of a tree. As they progress from fundamental measures to derived measures, they investigate such rates as speed and density. The supplemental CD-ROM features interactive electronic activities, master copies of activity pages for students and additional readings for teachers.