1. When a SCUBA diver dives below the surface of the sea the pressure exerted on their body will increase according to the formula P=ρgh. At a depth of 100m diver blows out a bubble of air with 2cm radius. How big will this bubble be just before it breaks the surface? Hint: Solution: 2. A SCUBA diver breathing air from an 18liter tank, on the surface, takes 0.5 litres of air into her lungs 20 times a minute.