u/Bitter_Bandicoot8067

I don't really know how to ask this question, so please bear with me.

If you have a container that is open to the atmosphere on top and open a drain on the bottom (such as a bath tub) in what order does the water flow out? (Does the bottom water flow out before the rest? Does the water just flow down?)

I know this is a probably a complex answer, so feel free to simply it for me. This is just something I am curious about.

I appreciate the help. I don't know how to phrase the question to be able to google it.