In previous grades, students learned that weight is a measurable attribute and directly compared the weights of two objects. In this lesson, students learn that weight is a measure of how heavy something is. They are introduced to grams and kilograms as metric units for measuring weight. Students hold objects of different numbers of grams and kilograms to familiarize themselves with the units before estimating the weight of objects in those units. Since the distinction between mass and weight is beyond what students need to learn in this grade, the term “weight” is used throughout the unit.

To build a sense of weight measurements and an intuition for comparison, it is extremely helpful for students to have the firsthand experience of holding different weights. To make that possible, some new materials and preparation are required for this lesson.