Each discipline of science has its own ways of doing research, e.g. social sciences primarily use qualitative and non-experimental methods, with occasional use of experimental methods.
Selected methods are natural observation, historical research, ethno-graphic research, cross-sectional study, longitudinal study, cohort study, case study, correlational research, model building, action research, and participatory learning and action (PLA).
Some of these methods are also employed by natural scientists.