Question

A miner working 900 ft below the surface had a soft drink beverage during the lunch break. To his surprise, the drink seemed very flat (that is, not much effervescence was observed upon removing the cap). Shortly after lunch, he took the elevator up to the surface. During the trip up, he felt a great urge to belch. Explain.

Answer 1

At a depth of 900 feet, the pressure of air i.e. the atmospheric pressure is much higher than the surroundings. When a beverage is opened, its internal pressure is usually higher than atmospheric. So effervescence is observed. At the depth of 900 feet, due to high atmospheric pressure, the difference is not much. So not much effervescence was observed.

As the miner came to the surface, he was moving to an area of low pressure. So the ingested CO2 rushed out to the area of low pressure. Hence he felt a great urge to belch.