A portable teaching tool for observing simple harmonic motion in vertical direction was fabricated using a coil spring. A photo-sensor and an X-T recorder were used to detect the oscillation. The regular intervals between the signal wave forms drawn on the recording paper were in good agreement with the period in the theory of simple harmonic oscillation. On the basis of the experimental results, this article describes the applicability of the teaching tool to student practice and demonstration lectures. The discussion includes a qualitative approach to amplitude from the angle of pedagogy of simple harmonic motion.
