Water Signs as the Three States of Water
Cancer is liquid. It can be a soothing rain or a devastating downpour. It's vast like the ocean and flows everywhere, but it's vulnerable in the sense that anyone can easily swim in it, drink it, pollute it. Of course the depths are a different story as you never know what's lurking in there...
Scorpio is solid. Think an iceberg, a gargantuan chunk of unwavering ice that would take an eternity to melt or chip away at. So cold that its mere presence cools whatever's around it. And while icicles may be sharp and snowstorms may be overwhelming, light snow showers are peaceful and the snowflakes themselves are beautiful, each one unique.
Pisces is gas. It can be formless like steam, or it can take any shape as a big cloud in the blue sky. Always floating, never in the same place. Unreachable, untouchable, unfathomable.