The Periodic Table
State the distinguishing properties of solids, liquids and gases
5 mins
1，引入：
演示物质变化的实验，要求学生观察变化前后物质的颜色、状态、并口头描述并记录实验现象。
[实验 1]水的沸腾
[实验 2]胆矾的研碎
[实验 3]蜡烛的燃烧
[实验 4]加热固体碘
讨论：什么是固体？什么是液体和气体？
2，讲解：
A solid, at a given temperature, has a definite volume and shape which may be affected by changes
in temperature.
A liquid, at a given temperature, has a fixed volume and will take up the shape of any container into
which it is poured.
A gas, at a given temperature, has neither a definite shape nor a definite volume.
3，例题：
4，课堂练习：
5，诊断：
6，作业：
