Question

A miner working $260\mathrm{m}$ below sea level opened a carbonated soft drink during a lunch break. To his surprise, the soft drink tasted rather "flat." Shortly afterward, the miner took an elevator to the surface. During the trip up, he could not stop belching. Why?

Short answer

The miner belched because CO₂ gas released from the drink under lower pressure builds up in his stomach, prompting belching.

Step-by-step solution

Understanding the Scenario

The miner opened a carbonated drink 260 meters below sea level. At this depth, the atmospheric pressure is higher than at sea level.

Pressure and Carbonation

Carbonated drinks contain dissolved carbon dioxide (CO₂). When the pressure is higher, as it is below sea level, more CO₂ can stay dissolved in the liquid. This is why the drink might taste flat, as less CO₂ is released as bubbles.

Effects of Reducing Pressure

As the miner travels up, the pressure decreases. Decreased pressure lowers the solubility of CO₂ in the drink, causing more CO₂ to be released from the liquid, thus increasing carbonation at sea level.

Belching Explained

The belching occurred because the released CO₂ gas from the soft drink builds up in the miner's stomach, leading to gas release through belching as the pressure equalizes with the decrease in ambient pressure.

Key concepts

Carbon Dioxide Solubility

In a carbonated drink, carbon dioxide ( CO₂ ) is dissolved to create fizz. However, how much CO₂ stays dissolved in the liquid depends heavily on pressure. The higher the pressure, the more CO₂ can dissolve into the drink. At a depth of 260 meters below sea level, the atmospheric pressure is much greater than at the surface. This increased pressure means more CO₂ remains dissolved in the soft drink. When the miner opened his drink underwater, it didn't fizz as much and tasted flat because a lot of CO₂ was still trapped in the liquid under pressure.

Atmospheric Pressure Effects

Atmospheric pressure plays a crucial role in the behavior of gases in liquids. Below sea level, the pressure is significantly higher than at sea level.

• High pressure allows more gas to dissolve into liquids, such as CO₂ in a carbonated drink.
• When pressure goes down, less gas stays dissolved, leading to more of it escaping.

This is why, when the miner began ascending to the surface, the pressure on the drink reduced, leading to an increased release of CO₂. As pressure decreases, the CO₂ that was dissolved in the drink under high pressure is no longer stable and escapes as bubbles.

Belching and Pressure Changes

Belching is often caused by gas building up in the stomach. In this case, the miner experienced belching because the carbonated drink released more CO₂ gas as the elevator ascended to the surface. The drop in pressure not only affected the drink but also the miner's digestive system:

• Decreased pressure helped more CO₂ escape from the liquid and enter the stomach.
• The body responds by releasing excess gas, resulting in belching.

The release of CO₂ through belching is the body’s way of adjusting to the rapid change in pressure as the miner ascends.

Submarine Pressure Differences

Underwater environments, like the depth of 260 meters where the miner was, exhibit pressure significantly higher than at the surface. This pressure directly affects how gases behave in different environments:

• Submarine pressures can keep gases like CO₂ dissolved in liquids longer.
• As you move to lower-pressure areas, like the surface, these gases are more likely to escape.

In a typical submarine environment, the higher pressure maintains the gas solubility, making activities like consuming carbonated drinks different from surface conditions. Understanding these differences can explain why carbonated drinks behave unusually at depth, similar to our miner's experience.