This research aimed to explore the effects of a virtual lab (VL) and a Microcomputer-based Lab (MBL) on students' performance in scientific modeling. A web-based virtual lab and a low-cost MBL were proposed to help first-year engineering students build scientific models. Empirical research was done in a slope motion experiment. The participants were 118 first-year engineering students in Taiwan, and they were divided into a VL group and an MBL group. From the results of the questionnaire, these groups of students thought that the systems were usable and easy to use, and they expressed positive attitudes towards the labs. The post-test's average score was higher than that of the pre-test for both groups, and the average posttest score of the VL group was better than that of the MBL group. From the students' learning sheets, many students successfully manipulated the experimental variables and built correct models after gradual revision of earlier models. According to the results of the empirical research, these systems helped the students understand the meaning of the experiment and increased students' interests with hands-on labs. A comparison of the results of these two groups suggests the integration of VL and MBL to facilitate students' learning.