Worksheets with various levels are major instructional material in open classroom, but sometimes they have been arbitrarily developed in elementaryschools. Especially, pedagogical elements of science course seem to have been neglected in developing science learning papers. To solve these problems, a model of worksheets was developed considering the contextual nature of science knowledge and educational constructivism. The frame of this model is composed of inquiry skill and context, which are two dimensions of each learning task. The level of each worksheet was determined by the level of inquiry skills and the familiarity of contexts.