Why are standard drinking cups shaped the way the are, wider on the top and more narrow toward the bottom?

Question

Wouldn’t it make more sense to have the cup be a consistent width throughout? Or, even make the cup wider at the bottom to make it more stable when sitting on a surface?

In: Engineering

Answer 1

It’s easier to stack a cup that’s wider at the top than one that’s the same width the whole way up or one that’s wider at the bottom. It also makes it a little easier to drink, but I don’t think that’s as much of a reason as the stacking since just making it wide enough to drink easily the whole way down would also work.