if you travel or if you're reading, particularly in older textbooks.

如果你们旅行或者读老些的课本的话
How does it work?

它的工作原理如何呢
Here was the first kind of experiment that I described earlier.

这是我先前讲的第一个实验
An X-ray source here, the X-ray source is emitting X-rays

这是X射线光源它发出X射线
in all different directions.

向各个方向发射
Some of them would impinge on this object,

有些就会接触到物体
and depending on the density of the material

根据物体密度的不同
within inside this object some of the X-rays would be absorbed

在物体内部一部分X射线被吸收
and some of them would pass through.

一部分则可以通过物体
In a dense part of the object, the X-rays would be absorbed,

在物体致密的部分 X射线会被吸收
in a less dense part, more of the X-rays would pass through.

在疏松的部分就有更多的X射线通过
If you put a piece of film or some kind of a detector behind the object

如果在物体后放上胶片或其他探测器