What you're seeing when you put it through a prism is that you heat hydrogen up and it doesn't just glow like a white light, it just emits light at particular colors, a red one, a light blue one, some dark blue ones.
把它透过棱镜时你看见的是， 你加热氢气，它并不会发出 白色的光， 它只发出特别的颜色的光， 一道红的，一道浅蓝的，一些深蓝色的。