By Glen Phelan
Units of Measurement: Sizing Things Up introduces students to units of measurement and how they are used in both scientific investigations and everyday life. Students learn that numbers and units go hand in hand—a measurement needs both to make sense. They compare different systems of measurement and investigate the tools used for measuring different physical properties, including mass, length, speed, and time. Students learn to distinguish between estimation and accurate measurements, and they explore the historical development of standardized units. At the end of each two-page spread, a brief statement called The Bottom Line reinforces students’ understanding by summing up the key ideas about units of measurement covered in those pages.