ABSTRACT Physical experiments on real-world systems are proposed as a means to raise learning outcomes and Arduino microcontroller is highlighted as an appropriate tool to perform them. However, experimentation on a real system may encounter various barriers. Therefore, a learning environment was developed in order to perform Arduino experiments on digital entities when the real ones are inaccessible. That was consisted of an Arduino-based pH meter from which measurements were transmitted to three different digital entities: a shoal of goldfish, an ancient Greek temple and an ancient Greek statue. In order to evaluate the learning outcomes of teaching through physical experiments on digital entities, a pre- to post-comparison was conducted on three Greek Junior High Schools. In each school, students were divided into two subgroups. The one group was taught about Acids and Bases through physical Arduino experiments by demonstration, using real instruments and substances, with a simultaneous observation of their effects on the digital entities in real-time, while the other group was taught through the same Arduino experiments by demonstration without the use of the digital entities. The results have demonstrated that students of the former group exhibited greater learning gains regarding Declarative Knowledge than those of the latter one.