Ballast is a material used to provide stability and weight to various structures, such as ships, trains, and even buildings. In ships, ballast is often water or heavy materials placed in the hull to lower the center of gravity, improving balance and preventing capsizing. In railways, ballast consists of crushed stone or gravel that supports the tracks and helps with drainage. In addition to its use in transportation, ballast can also refer to materials used in construction. For example, in concrete, ballast can be added to increase density and strength. Overall, ballast plays a crucial role in ensuring safety and stability in various applications.