Intelligent personal assistants (IPAs) carry massive potential in enhancing students' performance through individualized dynamic scaffolding strategy. Despite IPAs being increasingly recognized among educationists, little is known about their application in the development of students' scientific inquiry skills, particularly in physics. This study integrated the use of Apple's Siri in physics learning and examined the impact on secondary school student's scientific inquiry skills, and how these interactions affect their learning experiences. This mixed-method study conducted two field quasi-experiments (School A: science boarding school; School B: vocational boarding school) and post-experimental focus group discussions. Each school had two classes that were randomly assigned as experimental and control groups. The quantitative data showed that the experimental groups developed significantly higher scientific inquiry skills in comparison to the control groups (School A: p = 0.050; School B: p < 0.001) with moderate (d = 0.62) to large effect size (d = 1.82). The qualitative data further revealed the perceived ability of the IPA to support students' individualized learning by providing timely scaffolding. This study offers substantial empirical data to support the effectiveness of the IPA in increasing secondary school students' achievement in physics and scientific inquiry skills.