Turning points - Light Flashcards
What was Newtons corpuscular theory of light?
Newton hypothesised that light was made up of tiny, weightless particles, that travel in straight lines. He called this particles corpuscules.
How did Newton use his corpuscular theory to suggest why shadows occur?
Newton suggested that shadows are formed because when the corpuscles from the light source hit an opaque object, the corpuscles were stopped, and a shadow is formed. The greater the amount of corpuscles blocked, the darker the shadow.
Huygen could not explain why shadows are formed usig his wave theory.
What did Newton suggest about the colour of light?
Newton suggested that the corpuscles of light were coloured, and the different coloures travalled at different speeds due to different particle sizes.
Red travells slower, due due the corpuscles that make up red light having a larger size, compared the blue or violet who have smaller corpuscles and therefore travel slower.
What did Newton suggest about reflection and refraction using his cirpuscular theory of light?
During reflection, we know that the angles of incidence and reflection do not change. Newton said that during reflection, a corpuscles velocity component parallel to the mirror is unchanged.
During refraction, the angles of incidence and refraction are different, so Newton realised that a velocity change must occur.
Newton suggested that when light moves from a less dense medium to a more dense medium, like from air to water, the corpusculars velocity increases. Newton said that the for a more dense medium, the medium exerts an attractive force on the corpuscle which increases its velocity component at right angles to the surface.
While Newton’s corpuscular theory focuses on particle behavior and attraction/repulsion by the medium, Huygens’ wave theory describes light as a continuous wave process, explaining both refraction and reflection through the bending of wavefronts.
Why was Newtsons theory more widely accepted than Huygens?
- Due to Newtons higher reputation and scientific autority.
- Newton’s theory aligned more with the prevailing scientific thinking of the time, which often leaned toward particle-based explanations in nature.
- Newton’s corpuscular theory offered a simple, intuitive explanation for both reflection and refraction.
While Huygens’ wave theory could explain these phenomena too, it required more complex thinking about wave behavior, and the concept of waves was not as easily accepted at the time.
What was the significance of Youngs double slit experiment on Newtons theory of light?
Young found that light waves interfere, constructively and also destructively, causing bright and also dark fringes.
Newton predicted that there would be no pattern, the corpuscles would travel in straight lines, and there would be two bright regions directly behind the slits. Newton predicted there would be no diffraction, but indeed there was.
The double slit experiment strongly showed evidence for Huygens theory of light however.
