Comparing and Measuring focuses on activities that first graders enjoy on their own - finding out who's taller, what's longer, and what's farther. The explorations provide a solid groundwork for understanding that measuring is based on comparing and that the use of standard units enables people to work with and communicate size comparisons effectively.

The activities in Comparing and Measuring move students in steps from the concrete toward the more representational. Initially, students make general comparisons and observe that size is a common criterion on which comparisons are based. Then, students work together to:

• Make life-size cutouts of their bodies and use them to compare heights.
• Match strips of adding machine tape to their cutouts.
• Use the strips to make a bar graph of their resuslts.
• Match strips to the distances that they flip toy Flippers.

Following the matching activities, students move to measuring in units. By beginning with nonstandard units --their feet -- students see that nonstandard units produce different result. When different groups use a variety of standard units (toothpicks, coffee stirrers, spools, pencils), students see that results are consistent only among the groups using the same unit. When the class uses a common standard unit, the students see consistent results.

In the unit's final section, Unifix Cubes become the classroom standard. Students make and use paper measuring strips that represent 10 Unifix Cubes and discuss any observd advantages of the strips. By attaching several strips, the students make longer measuring tapes. In the final lesson, the students again use the Flippers, this time quantifying the distances by using their new measuring tapes.

By demonstrating the need for precise beginning and ending points, a common starting line, and standard units, Comparing and Measuring prepares students for formal measuring in units such as inches and centimeters.