In a previous unit, students described and compared the lengths of objects. In a previous lesson, students explored the difference between flat and solid shapes. In this lesson, students learn about an attribute of solid shapes: weight. Students are introduced to the terms “heavy,” “light,” “heavier,” and “lighter” to describe and compare the weights of objects (MP6). Students describe and compare the weights of objects when the comparison is visually obvious and brainstorm ideas for how to compare the weights when they cannot visually determine which object is heavier. Then students work in groups to compare the weights of objects and record the comparison. Since students will not be using a scale or a balance, objects to compare should have significantly different weights so that students can feel which object is heavier when holding them. In the Lesson Synthesis, students discuss a comparison of one heavier object and multiple light objects.