If you plant carrot seeds you will get carrots and if you design widgets you will get widgets. Our whole education system, under the pressures of NCLB, is designed to measure, and subsequently value, student retention of knowledge as opposed to their understanding of that knowledge. There's such a vast difference between knowing that the sun "rises" in the east to understanding what that means.
The financial pressures associated with being a "failing school" as measured by tests in language and mathematics mean there is little time for the type of activities required to develop deep understanding in science as opposed to simple recall as measured on spurious multiple choice questions.
In the early 1960s the US was devastated by the Russian Sputnik triumph. The next two decades were characterized by feverish investment in hands-on (now known as minds-on, hands-on) science in an effort to produce a nation of scientifically literate students. Programs such as ESS and SCIS (known as alphabet science programs because they all had acronyms) proliferated and science education had its golden era. Today, we struggle to get even a couple of hours a week of science education in most elementary school classrooms so it is no wonder that we are producing a nation of scientifically illiterate students.