The sinking of the Titanic in 1912 was not simply an iceberg collision; it was deeply related to buoyancy and the ship’s structure. Water flooding in from the collision reduced buoyancy, and ultimately, the ship could not overcome gravity and sank.
What comes to mind when you hear the word “Titanic”? Many people will recall the tragic love story of its two protagonists. However, in the field of shipbuilding, the Titanic is remembered as the worst maritime disaster in history, where a passenger ship collided with an iceberg, resulting in massive loss of life. This incident became such a major topic that it led to significantly strengthened passenger ship safety regulations. So how could a ship built so robustly, one that floated so well on water, sink simply from colliding with an iceberg? This question can be answered by understanding the principle of how a ship floats on water. Before explaining why the Titanic sank, I will first explain why a ship floats on water.
What does it mean for an object to float on water? It means the net force acting on the object is zero, signifying a state of equilibrium. Naver Encyclopedia defines this equilibrium state as “a condition where forces act upon an object, yet the object remains stationary.” Here, one can infer that besides the weight of the ship made of heavy steel plates, another force exists to counterbalance it. In physics, this is called buoyancy. An object submerged in a fluid like water or air receives a force from the fluid in the opposite direction of gravity; this force is called buoyancy. In other words, a ship can float because it is in a state of equilibrium where the magnitude of the gravitational force (the weight of the ship itself) equals the magnitude of the buoyant force generated by the ship floating on the water.
So why does a ship made of iron plates, which have the same weight, not sink? The key concept here is the magnitude of buoyancy. To understand buoyancy’s magnitude, consider Archimedes’ famous bath anecdote. Archimedes realized that the weight of the displaced water was equal to the buoyant force when he noticed the water pushed out as he entered the bath. This allowed him to determine whether a crown was made of real gold. In this story, the weight of water used to explain buoyancy is the product of volume and density. Here, volume refers to the amount of the object—the iron plate or ship—submerged in the fluid, while density refers to the compactness of the fluid displaced by the iron plate or ship. This demonstrates that buoyant force is proportional to both volume and density. A simple iron plate sinks because its volume is small, despite having the same weight and water density as the plate itself. Conversely, a ship, having the same weight and water density as the plate but a much larger volume, achieves a balance between gravitational force and buoyant force, allowing it to float. In other words, because a ship has a large submerged volume, its buoyant force is relatively greater than that of a simple iron plate, allowing it to float.
We have examined the principle enabling a ship to float on water through the preceding process. Now, we will explain why the Titanic, which was floating well, sank after colliding with an iceberg. As explained earlier, buoyancy is proportional to the volume submerged in water. To be more specific, this refers to the closed volume submerged in water. “Closed” here means the surfaces in contact with water have no holes or gaps, preventing water from entering the object’s interior. In other words, for a ship to receive buoyancy, water must not be able to enter its interior. When the Titanic collided with an iceberg, a hole was punched in the front left section of the ship. Water poured in through this hole, causing the ship to lose a portion of its enclosed volume. Consequently, the buoyant force decreased. As buoyancy became less than the gravitational force, the equilibrium of forces was lost, causing the ship to sink.
Through the sinking of the Titanic, we learned about buoyancy. To summarize the previous content: buoyancy is the force that balances the gravitational force acting on a ship, enabling it to float on water. Its magnitude equals the weight of the water displaced, which is proportional to the submerged volume of the object and the density of the water. Here, the submerged volume refers to the enclosed space without any openings for water to enter. The sinking of the Titanic sent shockwaves through the shipbuilding industry. The world responded by creating the SOLAS regulations, striving to minimize the volume of water displaced even if a ship collides with an iceberg. This represents the global effort to prevent another tragedy like the Titanic’s sinking.
The tragedy of the Titanic remains an event that transcends a simple love story, serving as a reminder of the importance of scientific principles and technology. It teaches us that we must understand the scientific concepts related to an object’s buoyancy and strive to achieve safer maritime transportation through this understanding.
