By Edwin Cartlidge | Copyright: New Scientist | Persian translation: Mahmoud Haj-Zamani | Re-typed and re-edited: Sky and Weather Network
Water is the most abundant—and arguably the most important—liquid on Earth. Its importance, however, is not limited to biological phenomena. Compared with other substances on Earth, water has remarkable physical properties, many of which can be regarded as factors that make it particularly compatible with life. [source]
X-ray image of water molecules.
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| Image from the original article |
The universe confronts us with many difficult mysteries, from the nature of dark matter and the origin of the universe to the search for a theory of everything. Yet an equally intriguing puzzle on a much smaller scale can be investigated in an ordinary kitchen. Fill a glass with cold water and drop in an ice cube. The familiar fact that ice floats is the first unusual property. Measure the temperature at different depths and another appears: near the ice the water is close to 0°C, while near the bottom it can be about 4°C. Water reaches its maximum density at about 4°C, an unusual behaviour that distinguishes it from ordinary liquids. [source]