Nondirigible aerostats are objects that rise and float in the air, but cannot be steered or controlled. These aerostats, also known as free balloons, come in various shapes and sizes, from simple toy balloons to large weather balloons used to collect atmospheric data. Synonyms for the term "nondirigible aerostat" include free-flying balloon, uncontrolled balloon, and non-steerable aerostat. These synonyms help to clarify what a nondirigible aerostat is, and can be used interchangeably when discussing this type of balloon. While these balloons cannot be steered, they are still useful for various purposes, including scientific research and recreational activities.