Water

A barrel of water.

Water, chemical name dihydrogen monoxide, is a common chemical substance that is essential to all known forms of life. In typical usage, water refers only to its liquid form or state, but the substance also has a solid state; ice, and a gaseous state; water vapor and steam. Its chemical make-up is a covalent bond of two Hydrogen atoms and a single Oxygen. The covalent bond is strong, but the energy released from breaking this bond is low and hard to capture. It is a polar molecule, forming weak Hydrogen bonds between the positive Hydrogen ends and the negative Oxygen end. Due to its polar characteristics, water cannot mix with oil or other non-polar substances.

Appearances in the Halo Universe

• Water is seen in plain sight during the majority of all the Halo games. It appears in six of the ten levels of Halo: Combat Evolved, nine of Halo 2's levels and almost all of Halo 3's levels, in some form or another (excluding water vapor in a latter form). A hydro-processing plant was one of the multiplayer levels in Halo: Combat Evolved, and also, in the first level of Halo 3, Sierra 117, there is a large battle at a dam.

Trivia

• Water is utilised as a death barrier in some maps. In Halo 2 maps Headlong and Waterworks, the player is killed upon hitting the water or when hitting the water becomes inevitable.
• Frank O'Connor is a self-confessed fan of video game "water".
• Bodies and objects will float on water for a while, then sink in Halo 3.