From the Latin scintilla (a spark in English), in everyday language it means to emit a flash of light like a spark. Flash of light. As a physical phenomenon, it is used to describe (1) the phenomenon in which a bright spot is observed momentarily when radiation hits an object (especially a fluorescent material), (2) the twinkling of a star, and (3) the phenomenon in which distant objects appear to flicker outdoors on a clear day. (1) was discovered independently by Elster and Geitel in 1903, and by Crookes. In the early development of atomic physics, Rutherford and Geiger used it to count the number of α (alpha) particles emitted from radium C (bismuth 214) and to measure the charge of the α particles from the accompanying current. It is still used today to detect charged particles, γ (gamma) rays, neutron rays, etc. (2) is a phenomenon in which stars close to the horizon twinkle violently due to atmospheric disturbances when observing them from the ground, and is described in Newton's Optics. (3) is also a familiar phenomenon that occurs for the same reason as (2). [Kouzo Ishiguro and Takahiro Kuga] [Reference item] |Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend |
ラテン語のscintilla(英語ではa spark)に由来し、日常語としては火花のようにぴかりと光を発する意。閃光(せんこう)。物理現象としては、(1)物体(とくに蛍光体)に放射線が衝突する際に瞬間的に強く輝く光点が観測される現象、(2)恒星のまたたき(twinkling)、(3)晴れた日に野外で遠くの物が揺らいで見えるかげろう現象、などを表す用語として使用される。(1)は1903年にエルスターとガイテル、またクルックスがそれぞれ独立に発見した。原子物理学発展の初期にはラザフォード、ガイガーがこれを使ってラジウムC(ビスマス214)から放出されたα(アルファ)粒子の数を数え、またそれに伴って流れる電流とからα粒子のもっている電荷を測定した。現在でも荷電粒子、γ(ガンマ)線、中性子線などの検出に使われている。(2)は地上で恒星を観測するときに大気の揺らぎのためにとくに地平線に近い星が激しくまたたく現象で、ニュートンの『光学』にもその記述がある。(3)も(2)と同様な原因で生ずる身近な現象である。 [石黒浩三・久我隆弘] [参照項目] |出典 小学館 日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について 情報 | 凡例 |
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