Benchmark 12C
Habits of Mind: Manipulation and Observation
Grades K-2, page 293

Measure the length in whole units of objects having straight edges.

NSES Content Standard A 
Science as Inquiry: Abilities necessary to do scientific inquiry
Grades K-4, page 122
Employ simple equipment and tools to gather data and extend the senses. In early years, students develop simple skills, such as how to observe, measure, cut, connect, switch, turn on and off, pour, hold, tie, and hook. Beginning with simple instruments, students can use rulers to measure the length, height, and depth of objects and materials; thermometers to measure temperature; watches to measure time; beam balances and spring scales to measure weight and force; magnifiers to observe objects and organisms; and microscopes to observe the finer details of plants, animals, rocks, and other materials. Children also develop skills in the use of computers and calculators for conducting investigations.

NSES Content Standard E 
Science and Technology: Abilities of technological design
Grades K-4, page 137
Implementing proposed solutions. Children should develop abilities to work individually and collaboratively and to use suitable tools, techniques, and quantitative measurements when appropriate. Students should demonstrate the ability to balance simple constraints in problem solving.