[目的]1.强化对杠杆原理的理解;2.提高动手能力和学习、应用科学的兴趣.[器材]圆柱形蜡烛一根、大号缝衣针1根、同样高低的玻璃杯两只、薄铁皮(或塑料板)1块、圆形小碟(或纸片)两只.[步骤]1.把蜡烛底端的蜡刮掉一些,让它像顶端一样露出烛芯.2.将缝衣针从蜡烛的中间穿过,应注意使穿孔稍微高于中轴线.6 [Objective] 1. To strengthen the understanding of the principle of leverage; 2. To improve the practical ability and learning, the interest of applied science. [Equipment] a cylindrical candle, a large needle, the same two glass, 1 sheet of thin sheet metal (or plastic plate) and 2 small round discs (or pieces of paper) [Procedure] 1. Scratch the wax at the bottom of the candle to reveal the wick like the top 2. Suture Needle through the middle of the candle, should pay attention to make the perforation slightly higher than the central axis