The benefits of developing children's computational thinking have been widely discussed with various approaches and learning tools. This paper reports the piloting of second-year longitudinal study, aiming to examine the effect of computational thinking education on the 5th grade students (n = 85) as they develop their algorithmic thinking and debugging skills. The results show that students benefited from our designed curriculum with learning gains in algorithmic thinking, especially in analyzing and finding the essential instructions to solve computational problems. Students also achieved significant gains in debugging programs. The study demonstrated that with age-appropriate learning materials and learning approach, even young children can develop computational thinking skills important to thriving in 21st century. This pilot study sets the direction of analyzing the rest of the Sth grade students' performance as well as the next year study.