# The shape of a bubble? [duplicate]

I have always wondered about a shape of a soap bubble. Why is it always spherical and not some other shape (like, cylindrical)? And why are the layers of the soap bubbles so thin? Also when someone tries to create a giant bubble, why does it burst so easily?

• possible duplicate of Why does a bubble take a spherical shape? Jun 4, 2015 at 7:47
• This question contains two subquestions. The first (about spherical shape) is a duplicate as @JohnRennie suggested. The second (about the bursting) is not, as far as I can tell. user237444: I suggest you rewrite your question to focus only on the second subquestion. Jun 4, 2015 at 9:17

## 1 Answer

The pressure acting on a bubble pushes on it. The bubble must move into the shape with the least pressure acting on it. The bubble, however, must maintain a constant volume. The shape with the smaller surface area for a constant volume is a sphere (the mathematical proof is complex), so the bubble takes on that shape.