其实，passage的生词并不多，但是在理解上会有些问题，所以做思维导图的时候应该会很痛苦。
Vocabulary
demonstrate 证明；操作示范
It is said that Galileo demonstrated that Aristotle's belief was false by dropping weights from the leaning tower of Pisa.
acceleration n.加速
(For example, the acceleration is twice as great if the force is twice as great.)
proportional 成比例的
…which states that every body attracts every other body with force that is proportional to the mass of each body.
rotation n.
For example, if one sets aside for a moment the rotation of the earth and its orbit round the sun, one could say that the earth was at rest and that a train on it was traveling north at ninety miles per hour or that the train was at test and the earth was moving south at ninety miles per hour.
改变参照物来进行研究
stub n. 烟蒂
stub out 把 ……熄灭
unambiguously 不含糊地
eclipses 日食，在The Science里其实有提到
propagation 繁殖 n.
equations n. 方程
infrared 红外线的
ultraviolet 紫外线的
postulate假设 assume
platinum铂
coordinate 坐标
ripple细浪
cease减少
decrease
geodesic区面几何
navigator领航人
navigation 导航
dynamic adj.有活力的
n.活力
