愛因斯坦玩具設計的改良與等效原理的教學應用

Re-production of Einstein's Toy And Its Related Teaching Applications

梁立國(Lih-Kuo Liang)

《物理教育學刊》 19卷2期 (2018/12) Pp. 21-30

https://doi.org/10.6212/CPE.201812_19(2).0003

摘要

愛因斯坦的最後一個生日(1955年3月14日)，鄰居Eric Rogers送他一個在自由落下重力消失瞬間，彈力將銅球拉回碗裡的玩具以演示廣義相對論中的普遍原理—等效原理。在此，我以高爾夫球取代銅球，扯鈴的半碗增加玩具的強度，長桿則以伸縮桿代替，高爾夫球可將一般實驗室所使用原長為20公分的彈簧拉長15公分；改良後的玩具大小適中、攜帶方便，且具有質量輕、重心低以及彈簧穩定性佳等特性，操作上也較為得心應手。在教學方面：等效原理的三種演示，可應用於非慣性座標運動時假想力的形成，包括電梯問題與繩張力計算；關於玩具設計的動力學機制是簡諧運動很好的演示教具；而運用重力與重力消失的概念，可以小孔孔徑與表面張力係數計算水滴在下落瞬間，球形半徑的值。

關鍵字

等效原理 ； 重力 ； 簡諧運動 ； 表面張力

並列摘要

At Einstein's last Birthday (March 14, 1955), his neighbor Eric Rogers gave him a toy that can pulls a copper ball back into the bowl when the toy fall as gravity disappears to demonstrate the principle of equivalence in general relativity. I replace the copper ball with golf, increase the strength with a bowl-shaped bell, the long rod is replaced by a flexible one. The weight of golf can stretch laboratory-used spring 15 cm long. This toy is moderate in size and easy to carry, and is also easy in operation for the stability of spring and its low center of gravity. In physics teaching: the equivalent principle of three kinds of demonstrations, can be applied to non-inertial coordinate motion of the formation of the imaginary force, including elevator and rope tension problems; The dynamic mechanism of toy is also a good design for the demonstration of the simple harmonic motion; And the concept of gravity vanishing can be used to calculate the value of the spherical radius from the pore aperture and surface tension coefficient.

並列關鍵字

principle of equivalence ； gravity ； simple harmonic motion ； surface tension