The purpose of this study was to compare the effect of Real Experimentation (RE) and Virtual Experimentation (VE) on pre-service teachers' understanding of scientific concepts in the domain of heat and temperature. A pre-post comparison study design was conducted that involved 182 undergraduate pre-service elementary school teachers enrolled in an introductory physics course on Heat and Temperature. The participants were assigned to three experimental groups (EG1=59 students, EG2=33 students, EG3= 34 students) and a control group (CG=56 students). The CG used RE to conduct the experiments, whereas the EG1 used VE. The EG2 and EG3 used a combination of RE and VE to conduct the same experiments. Conceptual tests were administered to assess students' understanding. Findings revealed that RE, VE, and the combination of the two methods appeared to be equally effective in promoting students' conceptual understanding in the domain of heat and temperature.