How does a drop of water get its shape?

If the drop is small enough, it is a perfect sphere. A sphere is the geometrical shape that has the smallest surface area for its volume. The drop takes this shape because water molecules are pulling inward toward each other, and tend to stick to each other. So when not confined by a container and with nothing around it to distort its shape a very tiny water drop is perfectly round like a ball.
If the drop is larger like a raindrop, it has domed top and semi- flattened bottom because as it falls, it must push the air out of its way. It is that upward push of the air being displaced that causes the falling drop to have a rather flattened bottom, so that it looks like a tear drop.

the bits of water piles up. this makes the dome shapes