system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how can my cat find my cup of water at night if water has no taste or colour?
gpt
I suspect you mean smell, not taste. (If it's tasting water, it's already found it.)

Water does have a smell, it's just that humans don't smell it. We don't need to, and it's better for us to be able to smell anything that's polluting the water (these smells would be drowned out if we were smelling the water). It's possible that other animals, such as cats, could smell water.

Also, it does have *some* color to it, but that's not really relevant. Even colorless things that are transparent can still be seen. You can see if a glass is empty or full. So can your cat.

Your cat has also probably learned that glass shaped things often contain water, so it doesn't need to look for water specifically, it needs to look for a glass. This is like when you want to go find water, you don't try to see the water or smell it, you look for tiled floors, because you know that's the kitchen and where water comes from.