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Phase transition (1934 words) |
 | Near the critical point, the fluid is sufficiently hot and compressed that the distinction between the liquid and gaseous phases is almost non-existent. |
 | This is associated with the phenomenon of critical opalescence, a milky appearance of the liquid, due to density fluctuations at all possible wavelengths (including those of visible light). |
 | For example, the critical exponents at the liquid-gas critical point have been found to be independent of the chemical composition of the fluid. |
| Special Circumstances: Critical Opalescence (660 words) |
 | Critical opalescence is a strikingly beautiful effect that is seen when water is heated to a temperature of 374 degrees Celsius under high pressure. |
 | In that critical state, the fluid is continually fluctuating between gas and liquid, and the fluctuations are seen visually as a multicolored sparkling. |
 | Galison uses critical opalescence as a metaphor for the merging of technology, science, and philosophy that happened in the minds of Poincaré and Einstein in the spring of 1905. |