Eli5: Why do all my cups and glasses have rims on the bottom that collect water in the dishwasher?

Question

Eli5: Why do all my cups and glasses have rims on the bottom that collect water in the dishwasher?

In: Other

Answer 1

Depending on the material, it also makes the cup more rigid. A plane is easily bent/folded/distorted because every direction can be a fold line. A convex shape doesn’t fold easily, so the shape is sturdier.