Scientific inquiry is widely accepted as a method of science teaching. Understanding its characteristics, called Nature of Scientific Inquiry (NOSI), is also necessary for a whole conception of scientific inquiry. In this study NOSI aspects were taught explicitly through student inquiries in nature in two summer science camps. Students conducted four inquiries through their questions about surrounding soil, water, plants, and animals under the guidance of university science educators. At the end of each investigation, students presented their inquiry. NOSI aspects were made explicit by one of the science educators in the context of the investigations. Effectiveness of the science camp program and its retention were determined by applying Views of Scientific Inquiry (VOSI-S) (Schwartz et al. 2008) questionnaire as pre-, post-, and retention test after two months. The patterns in the data were similar. The science camp program was effective in developing three of six NOSI aspects which were questions guide scientific research, multiple methods of research, and difference between data and evidence. Students' learning of these aspects was retained. Discussion about these and the other three aspects is included in the paper. Implications of differences between school and out-of-school science experiences are also discussed.