To address the issue of gender disparity in participation in the physics state matriculation exam, a novel school visit program was designed. The program was facilitated by undergraduate university students of physics and related courses who visited schools providing lower secondary education and delivered a single-session workshop including hands-on demonstrations of physics principles, presentations about famous female scientists, information on physics-related careers, and the importance of adopting a growth mindset. In this paper, we present a detailed description of the principles underlying the workshop's design and its final outline. Participants' responses to a pre-post questionnaire are analyzed to assess the immediate effects of the workshop, particularly as regards changes in their opinions about physics and students' intention to study it for their state matriculation exam. Female and male responses are analyzed separately to establish differences in the intervention's effect between the two genders. Results show an increase among female students with positive perceptions of their physics knowledge and familiarity with physics role models. Our attempt to boost confidence, enjoyment, and perceptions of the relevance of physics proved challenging but yielded some positive results. Strikingly, girls reported positive change in their ability to imagine themselves as physicists and their intention to study physics for their matriculation exam. The intervention was more successful among younger girls. Results obtained from boys were positive but to a lesser extent. The study demonstrates an encouraging and strong positive impact of a uniquely designed, single-session intervention, especially on adolescent girls, and contributes to research on the effectiveness of gender equality-oriented science outreach interventions.