In this research, we used practical experiential inquiry-based scaffold teaching in informal science education teaching about the soap industry, which was a community resource we wished to use in school lessons. Unlike basic hand-wash activities, we designed a ”Soap” teaching lesson. The designed lesson comprised four activities and an extended exercise. We used 105 fifth grade students as our research subjects, and used the Science Inquiry Learning Ability assessment (SILA) and the Achievement Testing of Soap Course (ATSC) to measure their learning over the teaching lessons and to compare the difference in learning between students with different learning inquiry ability. According to our study, ATSC F-test results show SILA high scoring students’ learning achievement is higher than that of SILA middle scoring students, and higher again than SILA low scoring students (p＜.01). Second, we find that most students from SILA high scoring group are capable of experiencing and reflecting. Not only could they generate their own conceptions or principles, but also apply the cardinal principle of soap preservation and solve problems which they encountered in the soap pilling exercise. Third, the SILA middle scoring student group had less sensitivity to the problems. They directly believed the data they had, but didn't think more about why this might happen. It appeared that they could provide various strategies, but not necessarily able to solve the problem. It was necessary for teachers to use scaffolding strategy to lead the students. Fourth, the SILA low scoring student group was in a passive position most of the time. They think conservatively and don't get on well with others. They recognized the natural phenomenon, but had no other ideas, and needed the teacher to give examples and guide them to finish the project.