Basic Information
Water is the liquid version of the substance also known as ice when solid, or steam when heated into a mist. Water is also often used as a general term to refer to that substance in any phase.
Chemical Properties
Compared to long chains of carbon molecules, water may seem somewhat simple, but don't let it fool you. It may only be made of two Hydrogen atoms, and one Oxygen atom, but H20 has a lot of surprising properties, and comes in many varieties. Water has two open atomic connectors, often referred to as hydrogen bonds. These cause water molecules to group together, stick to other substances via adhesion, and have a weak negative electric charge. This explains how water can act as the universal solvent, breaking down or carrying various other molecules. It also means that water forms larger structures of just water, from simple pairings of two water molecules, all the way up to elaborate 280-molecule patterns shaped like an icosahedron.
Even when cooled until solid, water has a variety of different crystaline patterns it can take, each with slightly different physical properties. While only two forms of ice naturally occur on earth, about 15 other exotic forms of ice can be made in a laboratory and are expected to exist in nature in other parts of the solar system. The temperatures and pressures at which water can exist in solid form, and the properties it has as ice, are fairly unique in the chemical world. Most liquids sink when frozen, but frozen water floats atop non-frozen water. If water behaved more like other liquids, it would result in lakes dying every winter, but instead the ice at the top insulates the water below it and life is preserved.
At room temperature and one atmosphere of pressure, water is a colorless, odorless liquid. It is almost transparent to light, blocking only a portion of the ultra-violet end of the spectrum, which can give it a faint blue color when observed in quantity. This transparency allows seaweed, plankton and other aquatic plants to grow underwater, and for fish and other aquatic animals to see.
Being "transparent" to our sense of smell, however, is a property of our noses, not the water. Humans have just never developed a fine-tuned water-sniffing organ, possibly because our bodies have other senses that can detect the humidity, feel, and sometimes sound of water, and possibly because there's so much water vapor in the air, we'd be constantly smelling it.
Biological Properties
Life as we know it requires water. Water is in every cell of life here on earth. It acts as a biological solvent, dissolving various chemicals into solution, so that they may be transported more readily via the body's cells. Water also helps regulate temperature within the body. It's likely then, that alien life evolving on other planets may have the same relationship we do with water. But it's far from guaranteed, as Alien Biochemistry may diverge significantly from our own.
Magical Properites
In most variations on the classical elements, water is listed as one of the four or five elements. Water elementals are usually depicted as the liquid form of water, rather than being clouds of water vapor or having bodies of ice.
Water-based magics include general elementalism as well as the narrower hydromancy. Dowsing and cloudbusting occupy a gray area between magic and psionics, and could be categorized as either depending on your game system. Some versions of cryokinesis may allow manipulation of ice, and this is a fairly common power in the superhero genre.
See Also:
- Boiling Point
- Fountain of Youth
- Drowning
- Gas
- Goldilocks Zone
- Homeopathic Medicine
- Hydrogen
- Ice
- Ice Nine
- Intertidal Zone
- Lake
- Liquid
- Non-Water Biological Solvents
- Ocean
- Oxygen
- Plumbing
- Polywater
- River
- Solid
- Steam
- Thirst
- Tides
- Triple Point
- Underwater
- Universal Solvent
- Water of Life
- Weather
Sources
Game and Story Use
- Water is a vital resource, especially in a desert or other arid climate. Many survival scenarios rely on it, and outdoorsman-type characters have a chance to shine in the gaming spotlight in such environments. ("Thanks, Fred, your Ranger really saved the party that time!")
- Opposite environments can be every bit as dangerous as well. See undertow, hypothermia, drowning, etc.
- Water rights, or the effects of irrigation or a major dam project could be the trigger for a war or other political conflict.
- An under-developed nation whose population exceeds their ability to provide fresh, clean water will end up having to either:
- buy water,
- take water by force,
- or suffer the consequences to the health of it's citizenry.
- An under-developed nation whose population exceeds their ability to provide fresh, clean water will end up having to either:
- It's likely that intelligent, tool-using life will only develop on planets somewhat similar to our own, with roughly the same amount of water. This may tightly confine what planets you can expect to find life on. See Goldilocks Planet.
- A planet with too little water (see Desert Planet), or water that only occurs as a gas or solid (see Ice Planet) may make some biological functions difficult. This might restrict life to the microscopic scale, if only small quantities of liquid water exist. Alternately, it may result in some creativity on the part of mother nature: see Alien Biochemistry and Non-Water Biological Solvents for ideas on how to evolve without water.
- A planet that's covered entirely in liquid water (see Water World) is likely to have life, but not highly-developed technological life. For one thing, they'd have a hard time ever discovering fire, which means no cooking, no smelting, and no combustion engine. While this still leaves open a few possible avenues of progress, it's rather hard to assemble a cuckoo clock while fighting against an underwater current. Just sayin'.
- The Mad Scientist or other villain has a plan to dry up, steal, or poison the water supply of an entire nation. Only the PCs can stop him!