The pressure inside a bubble is greater than the pressure outside the bubble when it forms. This indicates that the pressure on the bubble’s inner surface is larger than the pressure on its outer surface. As a result, there is a differential in pressure between inside the bubble and outside the bubble. To put it another way, there is too much pressure inside the bubble.

Pressure × Radius = Surface Tension

Here the pressure is Gauge Pressure, i.e. the difference between absolute pressure and atmospheric pressure

Thus, the ratio of gauge pressures is 1:2

Consequently, the ratio of radii is 2:1

We know that Volume ∝ radius3

Therefore the ratio of volumes is 8:1

A bubble will always have a spherical form. This is due to the bubble’s surface tension. The force produced by molecules on each other per unit length is known as surface tension. Due to surface tension, the bubble tends to occupy the smallest possible surface area, whereas the sphere has the smallest possible surface area. As a result, a spherical bubble is generated.