The current conditions in Indonesia show that student activities in the learning process tend to be passive which impacts factual knowledge. This study aims to analyze the effectiveness of concrete media in improving students' factual knowledge through observing activities. This study was quasi-experimental, designed in a non-equivalent post with only a control group. The population examined where the 4th-grade elementary school students in the 2013 curriculum pioneer school, Buleleng Regency. A total of 353 students were randomly sampled, and a group of 56 students was identified to take part. Data were collected on students' factual knowledge using objective tests. Data were analyzed using descriptive statistics, namely modus, median, mean, and inferential statistics, i.e., the t-test. The results of the t-test analysis with t-count were greater than the t-table, 5.46 > 2.00. Thus, it can be concluded that observing learning activities assisted by concrete media has a positive effect on students' factual knowledge in an elementary school. This finding will have implications that will lead to an increase in the factual knowledge of students in elementary schools by using concrete media through observing activities.