Ice is water frozen into the solid state. It can appear transparent or opaque bluish-white color, depending on the presence of impurities or air inclusions. The addition of other materials such as soil may further alter the appearance.
Ice appears in nature in forms of snowflakes, hail, icicles, glaciers, pack ice, and entire polar ice caps. It is an important component of the global climate, and plays an important role in the water cycle. Furthermore, ice has numerous cultural applications, from ice cooling of drinks to winter sports and the art of ice sculpting.
The molecules in solid ice may be arranged in different ways, called phases, depending on the temperature and pressure. Usually ice is the phase known as ice Ih, which is the most abundant of the varying solid phases on the Earth's surface. The most common phase transition to ice Ih occurs when liquid water is cooled below 0°C (273.15K, 32°F) at standard atmospheric pressure. It can also deposit from vapour with no intervening liquid phase, such as in the formation of frost.
Generally, a battle is a conceptual component in the hierarchy of combat in warfare between two or more armed forces, or combatants. In a battle, each combatant will seek to defeat the others, with defeat determined by the conditions of a military campaign. Battles generally are well defined in duration, area and force commitment.
Wars and military campaigns are guided by strategy, whereas battles take place on a level of planning and execution known as operational mobility. German strategist Carl von Clausewitz stated that "the employment of battles ... to achieve the object of war" was the essence of strategy.
The definition of a battle cannot be arrived at solely through the names of historical battles, many of which are misnomers. The word battle is a loanword in English from the Old French bataille, first attested in 1297, from Late Latin battualia, meaning "exercise of soldiers and gladiators in fighting and fencing", from Late Latin (taken from Germanic) battuere "beat", from which the English word battery is also derived via Middle English batri, and comes from the staged battles in the Colosseum in Rome that may have numbered 10,000 individuals.