Matter and its changes.
物质及其变化。
Matter can change in many ways.
物质可以以多种方式变化。
You can tear, bend, or fold a solid.
你可以撕裂、弯曲或折叠固体。
The solid will look different, but it is still the same thing.
固体看起来会不同，但它仍然是一样的东西。
However, matter can change into something else.
然而，物质可以变成别的东西。
When you burn wood, it changes into ash.
当你烧木头时，它会变成灰烬。
You can mix things and make a mixture.
你可以混合东西，使混合物。
A mixture is two or more kinds of matter put together.
混合物是两种或两种以上的物质放在一起。
When you mix solids, they don't change and they are easy to separate.
当你混合固体时，它们不会改变，而且很容易分离。
But some mixtures are hard to separate.
但是有些混合物很难分离。
When you put a solid into a liquid, some solids will dissolve and make a mixture.
当你把固体放入液体中时，一些固体会溶解并形成混合物。
If you put sugar into hot water, it is hard to separate the sugar from the water.
如果你把糖放进热水里，很难把糖和水分开。