Physics 1: Particle Theory of Light by YcZNzQ2v


									Physics 1:
Particle Theory of Light

Group 1
II – Camia
Sir Delfin Angeles
Topics to be discussed:
 Corpuscular Theory of Reflection
 Newton’s Arguments
 Corpuscular Theory of Refraction
Unusual Terms:
 Corpuscle - a particle of matter, as an electron, proton, or
 Electromagnetic radiation – produced by the movement of
  electrically charged particles. They travel through empty
  spaces, air, and other materials
Contributors to the Discovery of
1.    Leucippus
           – when he was walking with his student Democritus, they observed that
      water looks like one solid object., but when you touch water, the particles can be
      seen. Same goes for the sand at the beach
           – suggested that matter can be broken down into smaller pieces until they
     become indivisible
           – called these tiny particles “atomos” which means indivisible
2.     Aristotle
           – did not agree with Leucippus’ and Democritus’ theory
            – “Why does matter not fall apart when blown by the wind or washed by
     water, if they are composed of tinier particles?”
           – stated that matter is made up of 4 elements; fire, water, wind, and earth
     (postulated by Empedocles in the fifth century BC)
           – matter was continuous all of one piece
            – other scientists agreed with Aristotle. It was not until 18th century when
     the atom’s indivisibility was retested
Contributors to the Particle Theory
1.   John Dalton
         – studied the works of French chemists Antoine Lavoisier
     and Joseph Louis Proust, and made the following
     conclusions/postulates in 1808
                   – All atoms of the same element are identical, but
     they are different from the atoms of other elements. They are
     unchangeable. According to him, “The atoms never can be
     metamorphosed one into another by any power we can control.”
                   – During chemical reactions, atoms are neither
     created nor destroyed (Lavoisier’s Law of Conservation of
                   – Atoms which form a compound always combine in
     definite whole number proportions (Proust’s Law of Definite
Contributors to the Particle Theory
2.   Robert Boyle (1627-1961)
        – postulated that gases are composed of discrete particles
       separated by a void
3.   Isaac Newton
        – “God in the beginning formed matter, in solid, massy, hard,
           impenetrable, movable particles…”
Particle Theory of Matter
   Also known as the Kinetic Theory of Matter
   A theory which states that matter is made up of small particles which are moving
   Around 17th century, experimental evidence in support of particulate theory
   The degree to which the particles move is determined by the amount of energy
    that they have and their relationship to other particles

The Particle Theory states that:
1.   Matter is made up of tiny particles (atoms and molecules).
2.   Particles of matter are in constant motion.
3.   Particles of matter are held together by very strong electric forces.
4.   There are empty spaces between the particles of matter that are very
     large compared to the particles themselves.
5.   Each substance has unique particles that are different from the particles
     of other substances.
6.   Temperature affects the speed of the particles. The higher the
     temperature, the faster the speed of the particles.
The Particle Theory explains that:
1. Pure substance are homogenous. (One phase
   – one unique kind of particle)
2. Physical Changes – melting, evaporation,
   sublimation, dissolving, etc.
3. Characteristic Physical Properties – density,
   viscosity, electrical and thermal conductivity,
What is Light?
 Light is a range of electromagnetic radiation
  that is visible to the human eye.
 In Physics: Light refers to electromagnetic
  radiation of any wavelength whether visible or
   Made by Italian Franciscan
    alchemist Geber
   It is a postulate which states that all
    physical bodies possess an inner and
    outer layer of corpuscles
   Used by Newton in developing the
    Particle Theory of Light
Who is Isaac Newton?
   English physicist, mathematician,
    astronomer, natural philosopher,
    alchemist, and theologian
   He is became famous because of his
    works in mathematics, optics,
    mechanics, and gravitation
    Corpuscular Theory of Light
   It is a theory made by Isaac Newton which states that
    light is made up of small corpuscles that travel in a
    straight line (rectilinear propagation) with a constant
    velocity and possess kinetic energy
Corpuscular Theory of Reflection
   A particle incident on a surface has components of its
    velocity in both the X and Y directions. The X
    component must then remain the same if the force
    on the particles acts perpendicular to the surface.
    The Y component of velocity is just reversed since
    the kinetic energy remains constant. This would make
    the angle of reflection equal to the angle of incidence
Corpuscular Theory of Refraction
   The thought that light bends towards the normal when moving
    from air to water can be demonstrated. Newton believed that
    water attracted light particles, therefore, the particle’s velocity
    increased. This increase in velocity would cause its path to bend
    towards the normal.
    This could lead Newton to predict that the speed of light in water
    was greater than in air. In 1850, Foucault showed that light
    travelled slowly in water than in air. The particle theory seems to
    be wrong.
Contradictions to Newton’s Theory
   The mass of the source remains unchanged due to emission of
    material particles, via the corpuscles.
   Simultaneous refraction and reflection of light from transparent
    surfaces could not be accounted for.
   The speed of light in a denser medium turns out to be greater than
    the speed of light in a rarer medium, according to Newton's theory.
    Experimentally, its exact opposite is found to be true.
   Other phenomena like interference, diffraction, polarization, etc.
    could not be explained through Newton's corpuscular theory.
                       The Clash of the Nerds!
May proofs ako!
Wala kayong laban sa
theories ko!             And BTW,
                         Who’s better and more

   Sir Montales’ PPT Presentation
Group 1 - Members
   Mikee Empleo – leader, researcher, cheerleader
   Edmond Bries – researcher, actor: enemy of newton
   Radney Doromal – maker of the ppt. presentation, researcher, lol-er
   Ian Ilagan – researcher, paraphraser, scriptwriter, printer
   Ramon Marquez – actor: newton, mascot: particles

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