Why are plastic coke bottles made with bumpy bottoms?

Answer 1

Its to make the plastic more durable. Over the years the plastic bottles are getting thinner to save money and its better for the environment. So in doing so the weakest ends are the top and the bottom. the top and the bottom is a little denser then the rest of the bottle. All plastic bottles are different on the bottom, but they have the same density. Coke chose this one for looks as well.

Answer 2

to keep it standing up on not flat surfaces =] like if you are in a beach or sumthin it will balance out. Also becuase it looks cool i guess =] =]

funn question!!