Question

whu bubbles expand as they rise to the surface

Answer 1

The bubble gets bigger when it go up to the surface because there is less pressure as it rises to the surface.Air is less dense than water and thus the force of gravity is less on the bubble than on the surrounding water then the bubbles rise.

Answer 2

The bubble gets bigger when it go up to the surface because there is less pressure as it rises to the surface. Air is less dense than water and thus the force of gravity is less on the bubble than on the surrounding water then the bubble rise .