12 牛頓的粒子論怎樣解釋折射定律？當炮彈抵達水面時，會受到與水面成直角的「折射力」影響，因而減慢速度，並偏離法線。光線的表現則剛好相反。要解釋這個觀察現象，牛頓假設光在水中的前進速度較快，所以會偏向法線。（這個解釋有甚麼問題？）問題：光在水中的速度真的較快嗎？在牛頓和惠更斯的年代還沒有人能測量光的速度空氣炮彈光Newton thus described the nature of light as follows (the theory was closely linked to his mechanics): it comprises corpuscles of different masses emitted by a source; these are propagated in space at a tremendous velocity. When they reach the surface of a medium, these particles are acted upon by a refracting force, excited by them, which is perpendicular to the surface and proportional to the density of the affected body and acts at a short distance from it. This force, deflecting the trajectory of the corpuscles, causes reflection, refraction, dispersion and what Grimaldi called diffraction.水
20 科學定律是對大自然現象間的關係或規律的描述。 甚麼是科學定律？甚麼是科學理論？科學定律是對大自然現象間的關係或規律的描述。例子：理想氣體定律PV = nRT科學理論是對這些關係或規律的解釋。The followings are definitions of a law and a theory.Laws are generalizations, principles or patterns in nature. (McComas, 1998)Laws are descriptive statements of relationships among observable phenomena. (Lederman et al., 2002)Theories are the explanations of those generalizations. (McComas, 1998)Scientific theories are well-established, highly substantiated, internally consistent systems of explanations.(Suppe, 1977, cited in Lederman et al., 2002)例子：分子運動論
35 研究光電效應的裝置中（如下所示），要量度光的強度、光的頻率、所產生的電壓和電流的大小。 愛因斯坦的光電效應實驗提供了甚麼證據支持光粒子理論？Teaching notes: According to the wave theory, the strength / intensity of light is in proportion to its brightness: a bright light should have been plenty strong enough to create a large current.e-Light光
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