All of these experiences lay the foundation for an understanding of how weight affects balance. They begin their investigations by exploring different ways to balance objects. They then examine different strategies for comparing objects. Later, they compare one object with a standard unit to determine its weight. In the first five lessons, students explore balance through a number of activities, such as building structures, observing a beam balance, and creating mobiles.
Students begin by describing their ideas about balance and how weight affects it.
They then construct and explore a beam balance. They discover the important role that weight plays in balance and how a fulcrum can be moved to compensate for unequal or unevenly distributed weight. They apply these concepts to the task of building mobiles in Lesson 5. In Lessons 6 through 9, students begin to compare objects. To do so, they use a tool called the equal-arm balance.