圓盤風扇陀螺之設計及其進動現象之分析

圓盤風扇陀螺係採用電力驅動的風扇，風扇馬達則固定於圓盤上。當風扇高速旋轉時，圓盤可藉由動態平衡直立起來，並隨風扇進動旋轉。本實驗設計考慮了光碟（直徑約12cm）與塑膠圓盤（直徑約18cm）兩種不同面積的圓盤，再利用鐵墊片、磁鐵及連接線變換等方式，設法控制角動量與淨外力矩的變化。光碟與塑膠圓盤的實驗結果皆顯示角動量愈大或淨外力矩愈小，圓盤進動旋轉現象愈不明顯，而角動量或淨外力矩的方向改變皆能造成圓盤進動旋轉方向改變。這些結果大致與理論預測相符。其中面積較大的塑膠圓盤雖可直接吸附磁鐵探究淨外力矩的影響，但相對也會受到較大風扇導引氣流的影響，以致實驗結果與理論預測有些差距。

關鍵字

進動；動態平衡；陀螺

並列摘要

The device of disk-fan spinning top is made of an electricity-power fan fixed on disk. When the fan spins at high speed, the disk can rotate due to the fan's precession and stand vertically due to dynamical equilibrium. The experimental design considers two different sizes of plates: a CD (about 12 cm in diameter) and a plastic disk (about 18 cm in diameter). We use the iron pad and the magnet, or change the connecting wire to control the variation of the angular momentum and the net torque. Results show that the bigger angular momentum or smaller net torque causes the less obvious precession phenomenon. Moreover, the different direction of the angular momentum and the net torque cause the different direction of the precession. Our results almost correspond to theoretical predictions. Although the larger plastic disk can directly be attached a magnet to explore the influences on net torque, it is affected by larger airflow, occurring some deviation between the experiment result and the theoretical prediction.

並列關鍵字

precession ； dynamic equilibrium ； spinning top

國際替代計量

圓盤風扇陀螺之設計及其進動現象之分析

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