NSES Content Standard E  
Science and Technology: Understanding about science and technology 
Grades K-4, page 138 

Tools help scientists make better observations, measurements, and equipment for investigations. They help scientists see, measure, and do things that they could not otherwise see, measure, and do. 

Benchmark 3A The Nature of Technology: Technology and Science
Grades K-2, page 44
Tools are used to do things better or more easily and to do some things that could not otherwise be done at all. In technology, tools are used to observe, measure, and make things.