sciencehabit writes "The first-ever use of interactive computer tasks on a national science assessment suggests that most U.S. students struggle with the reasoning skills needed to investigate multiple variables, make strategic decisions, and explain experimental results. The results (PDF) are part of the National Assessment of Educational Progress that was given in 2009 to a representative sample of students in grades four, eight, and 12. What the vast majority of students can do, the data show, is make straightforward analyses. More than three-quarters of fourth grade students, for example, could determine which plants were sun-loving and which preferred the shade when using a simulated greenhouse to determine the ideal amount of sunlight for the growth of mystery plants. When asked about the ideal fertilizer levels for plant growth, however, only one-third of the students were able to perform the required experiment, which featured nine possible fertilizer levels and only six trays. Fewer than half the students were able to use supporting evidence to write an accurate explanation of the results. Similar patterns emerged for students in grades 8 and 12."