Why do corpses float

Corpses float in water primarily due to the accumulation of gases within the body that are produced during decomposition. Here’s how this process works:

1. Initial Sinking

• When a body first enters the water, it is usually denser than the surrounding water because it has a high concentration of soft tissues and limited trapped gases. As a result, it initially sinks.

2. Decomposition and Gas Production

• After death, bacteria within the body begin breaking down tissues, a process that produces gases like methane, carbon dioxide, and hydrogen sulfide. These gases accumulate in the body cavities, particularly in the chest and abdomen.
• The gas buildup causes the body to expand, reducing its overall density relative to the water, which provides buoyancy. This increase in buoyancy causes the body to eventually float to the surface.

3. Factors Affecting Floatation

• Water Temperature: In colder water, decomposition is slower, so gas buildup takes more time, delaying the floating process. In warmer water, decomposition happens faster, causing the body to float sooner.
• Body Composition: Individuals with higher body fat may float sooner because fat is less dense than muscle and has natural buoyancy.
• Time and Exposure: Bodies in water for longer periods may sink again once the gases escape or if other environmental factors (such as animal activity or water currents) disrupt the body.

4. Flipping

• Typically, the gases in the chest and abdomen make the torso more buoyant than the limbs and head, often causing the body to float face-down, particularly in the case of human corpses.

Summary

A corpse floats in water due to gases produced during decomposition, which increase buoyancy and bring the body to the surface. This phenomenon is influenced by temperature, body composition, and the time spent in water.