In both cases, high concentrations of the gas are dark, while low concentrations are light.

在两幅图中，气体密度越高的区域颜色也就越深，低密度区则更浅。

youdao

In both cases, high concentrations of the gas are dark, while low concentrations are light.

在两幅图中，气体密度越高的区域颜色也就越深，低密度区则更浅。

youdao