philosophy of science
falsafe-ye dâneš (#)
Fr.: philosophie des sciences
The critical study of the basic principles and concepts of a particular branch of knowledge. The philosophy of science is particularly concerned with the nature of scientific facts, the structure of scientific statements, and relations between them.
From New Latin, from Gk. phlogiston, neuter of phlogistos "inflammable, burnt up," from phlogizein "to set on fire, burn," from phlox "flame, blaze;" from PIE root *bhel- "to shine, burn."
Fložiston, loan from Fr, as above.
An obsolete theory of combustion in which all flammable objects were supposed to contain a substance called → phlogiston, which was released when the object burned. The existence of this hypothetical substance was proposed in 1669 by Johann Becher, who called it terra pinguis "fat earth." For example, as wood burns it releases phlogiston into the air, leaving ash behind. Ash was therefore wood minus phlogiston. In the early 18th century Georg Stahl renamed the substance phlogiston. The theory was disproved by Antoine Lavoisier in 1783, who proved the principle of conservation of mass, refuted the phlogiston theory and proposed the oxygen theory of burning.
The inner → satellite of → Mars orbiting less than 6,000 km above the surface of Mars, closer to its → primary than any other → moon in the → solar system. Phobos is irregularly shaped, 27 x 22 x 18 km in size and orbits Mars in 0.319 days. Phobos' orbit is decaying at a rate of about 2 centimeters per year; it is therefore expected to break up and crash onto Mars within the next 50 million years. See also: → Roche limit, → orbit decay.
In Gk. mythology, Phobos is one of the sons of Ares (Mars) and Aphrodite (Venus). The name means "fear, panic, flight."
The outermost of Saturn's known satellites, also known as Saturn IX. It is 220 km in diameter and orbits Saturn in 550.5 days at a distance of 12,952,000 km.
In Gk. mythology, Phoebe is the daughter of Uranus and Gaia; grandmother of Apollo and Artemis.
Fr.: anneau de Phœbé
A giant ring around Saturn spanning an area of space from a distance of ~ 128 Saturn equatorial radii, RS (60,330 km) to 207 RS, that is, from about 7.7 × 106 to 12.4 × 106 km from the planet. Its vertical thickness is about 40 RS. The Phoebe ring was detected in 2009 using NASA's infrared → Spitzer Space Telescope. The Phoebe ring is made up mainly of dust particles about 10 to 20 microns in size, or about one-tenth to one-fifth the average width of a human hair. Rocks that are the size of soccer balls or larger with diameters of more than about 20 cm make up no more than about 10 percent of the ring (Verbiscer et al., 2009, Nature, 461, 1098).
L. Phoenix, also phenix, from Gk. phoinix a mythical bird of great beauty which according to one account lived 500 years, burned itself to ashes on a pyre, and rose alive from the ashes to live another period.
Qoqnos, from Ar., from Gk., as above, or, for some reasons (mistake?), from Gk. kuknos, → Cygnus.
A speech sound considered as a physical event without regard to its place in the sound system of a language.
From Gk. phone "voice, sound," phonein "to speak;" cf. L. fama "talk, reputation, fame."
Âva "voice, sound," related to âvâz "voice, sound, song" (both prefixed forms), bâng "voice, sound, clamour" (Mid.Pers. vâng), vâžé "word," variants vâj-, vâk-, vâ-, vâz-, vât-; Av. vacah- "word," vaocanghê "to decalre" (by means of speech), from vac- "to speak, say;" cf. Skt. vakti "speaks, says," vacas- "word;" Gk. epos "word;" L. vox "voice;" PIE base *wek- "to speak."
The smallest phonetic unit in a language that can distinguish one word from another.
From Fr. phonème, from Gk. phonema "speech sound, utterance," from phonein "to sound," → phone.
Vâj "voice," variant of vâž, vâz-, âvâz etc., → phone.
A branch of linguistics dealing with the analysis, description, and classification of speech sounds. More specifically, phonetics deals with the physical production of → phonemes regardless of language, while → phonology studies how those sounds are put together to create meaningful words in a particular language.
A combining form meaning "sound, voice," used in the formation of compound words. Also phon-, especially before a vowel.
From Gk. phon-, phono-, form → phone "voice, sound, speech"
A branch of linguistics that studies the rules in any given language that govern how → phonemes are combined to create meaningful words. Phonology and → phonetics study two different aspects of sound, but the concepts are dependent on each other in the creation of language.
A quantum of vibrational or acoustic energy in a crystal lattice, being the analog of a photon of electromagnetic energy.
A specific type of → photoluminescence that continues for an appreciable time after the stimulating process has ceased. Phosphorescence is due to the existence of metastable → excited states of the atoms and molecules from which a change to the normal state is hindered for some reason or other. The change from the → metastable metastable state to the normal one becomes possible only as a result of some additional excitation, for example the application of heat.
1) fosfor (#); 2) rujâ, setâre-ye bâmdâdi (#)
1) Nonmetallic chemical element; symbol P. → Atomic number 15;
→ atomic weight 30.97376;
→ melting point 44.1°C;
→ boiling point about 280°C. It
was discovered by the German merchant Hennig Brand in 1669.
L. Phosphorus "morning star," from Gk. Phosphoros "morning star," literally "light bearing," from phos "light" + phoros "bearer," from pherein "to carry," cognate with Pers. bordan "to carry, lead" (→ periphery). The chemical element is such called because of its white color.
1) Fosfor, loan from Fr.
The supersymmetric partner of the → photon.
From phot, from → photon + -ino supersymmetric particle suffix.
šid- (#), nur- (#)
From Gk. combining form of phos (genitive photos).
Šid- "light, sunlight," from Mid.Pers. šêt "shining, radiant, bright;"
Av. xšaēta- "shining, brilliant, splendid, excellent."
A situation in which all of the energy of a photon is transferred to an atom, molecule, or nucleus.
Electrode capable of releasing electrons when illuminated.
The study of the chemical and physical changes occurring when a molecule or atom absorbs photons of light.