The causal model is a specific relational pattern for the cause and effect of a phenomenon in learning with a causalitic-thinking approach (CTA) (causalitic means a combination of causality and analytic). This approach is oriented to increasing the problem-solving ability (PSA) of pre-service teachers and has been implemented in two subjects: work and energy, and thermodynamics. PSA includes the ability to understand (IPSA-1), select (IPSA-2), differentiate (IPSA-3), determine (IPSA-4), apply (IPSA-5), and identify (IPSA-6). This research aimed to investigate causal models in learning Physics, which are possible to develop for increasing PSA. This research was conducted by using a mixed method of an embedded, experimental, two phase design and used a sample of 49 students, with 39 females and 10 males. The differences between pre-test and post-test, and between the PSA gain of the low (Lo) and high (Hi) groups were tested using the Wilcoxon signed-ranks test. Results of the test on the subjects, among all pairs (24 pairs) of t_counted and t_table, showed that there are differences of 71% (for pre- and post-test) and 33% (for Lo and Hi groups) that indicated t_counted<t_table. However, from the investigation of the physics phenomena used, there are six causal models as a result of the first year of this series of research. The models are simple causal model (SCM), divergent causal model (DCM), convergent causal model (CCM), chain causal model (ChCM), simple composite causal model (SCoCM), and chain composite causal model (ChCoCM). These models are useful as references when constructing phenomena for conducting Physics learning or learning for another discipline using this approach.