Lights and Optics: Newtons Particle Theory - Essay Example

?Light and Optics What is Light? Light is a component of the electromagnetic spectrum, which in turn is a collection of waves. These waves include Microwaves, X-Rays, radio waves, Gamma Rays, and visible light. Near the end of the 17th century, concerns regarding whether light is composed of waves or particles surfaced (“Theory of Light”). The idea of light being composed of tiny particles was proposed by Sir Isaac Newton. Christian Huygens, the Dutch physicist proposed the idea of light being composed of waves in 1678 (“Theory of Light”). He asserted that such waves vibrate in the perpendicular direction to the direction in which light travels. This theory formulated a new way of visualization of the propagation of waves called as “Huygens” Principle. Newton’s Particle Theory Newton’s particle theory of light is also known as the Corpuscular Theory of Light. Newton published Opticks in the year 1704, 17 years after the publishing of Principia (“Newton’s Particle Theory”). In Opticks, Newton said that light is made up of little masses, which implies that a horizontal light beam near the earth forms a parabola, thus undergoing a projectile motion. The immensity of the speed of particles of which light is composed is the reason why it is observed as a straight line in spite of its projectile motion. The speed of the travelling of light is 300m per microsecond, during which “it should fall a distance y = 1/2gt2 = 5*10-12 m, much too small to be seen” (“Newton’s Particle Theory”). The particle model easily explained a range of the then known properties of light. For instance, it explained why the angle of incidence and the angle of reflection of light were equal as light reflected from a smooth surface. This also explained the phenomenon of bouncing back of a frictionless elastic ball from a smooth surface. Refraction is a major property of the particle theory of light. Certain experiments carried out on the light theory at the time led to some unexplained phenomenon. Newton did not explain the light interference phenomenon, which became the basis of the particle theory of Newton being in support of the wave theory. It was mainly the polarization of light that caused this difficulty. Scientists knew that the motion of wave was in parallel direction to the wave travel’s direction rather than perpendicular to the wave travel direction as happens in the case of light. Although the Corpuscular Theory of Light could explain the phenomena of primary and secondary rainbows, yet it failed to lay down an appropriate explanation of the supernumerary bow, the iridescent cloud, or the corona. The Wave Theory of Light Huygens proposed a successful theory of the wave motion of light in three dimensions. In this theory, Huygens said that light wave emerges from surfaces like onion’s layers. Light waves are spherical in uniform mediums or vacuum. As the wave surfaces propagate with the speed of light, they spread out. According to Huygens, gravity does not affect the light waves. Huygens disagreed with Newton saying that the speed of light reduces as it travels from air to water whereas it increases when it moves from water to air. Later, Huygens was found to be correct. Each color exhibited by the wave as it spreads out from the source carries a different wavelength. Supernumerary bows could be explained with the assumption of light as a wave. Huygens wave theory elaborates the reason why light spreads out of a slit or a pin hole instead of making a straight line. Although the theory of Newton preceded Huygens’s, yet early experiments were explained better by the theory of Huygens. Huygens’s principle can be used to assess the location of a certain wavefront in the future if its present location is known. The Dual Nature of Light In the year 1803, Thomas Young shone light through a screen to study the interference of light waves. The screen had two equally separated slits. As light passed through them, it emerged spreading out following the Huygen’s principle. The two wave fronts eventually overlapped. At the point of overlap of the waves, a screen placed reflected the production of dark and light areas. Augustin Fresnel provided mathematical calculations in support of the experiments conducted by Young in the year 1815 (“Theory of Light”). Existence of a quantum of light was proposed by Max Planck in 1900 in terms of a finite energy packet that relied on the velocity and frequency of the radiation (“Theory of Light”). It was in 1905 when Albert Einstein suggested a solution to the behavior of light that was observed to exhibit the characteristics of the particle theory and the wave theory simultaneously. Referring to Plank’s work upon the light’s emission from the hot bodies, Einstein proposed that light is made up of photons, which are tiny particles carrying energy. The theory of light branches into the quantum mechanics physics whose concept was understood in the twentieth century. Quantum mechanics explores the nature’s behavior on the atomic or even smaller scale. Quantum mechanics confirmed that light has a dual nature, thus refuting all contradictions. Light Wave Theory Although light simultaneously exhibits particle theory and wave theory, yet it exhibits the behavior of a wave for most of the time. Around the mid-19th century, James Clark Maxwell showed that electromagnetic waves could propagate through the empty space by developing an oscillating electric circuit. This paved way for the establishment of the electromagnetic nature of light. According to the modern light theory, light is composed of photons that are small packets carrying the electromagnetic energy, that travel at a constant speed. However, their speed in a vacuum is faster compared to that in the atmosphere, whereas the speed of photons in water is slower compared to what it is in the air. Since light waves are composed of electric as well as magnetic fields, they are known as electromagnetic waves. The direction of oscillation of the electromagnetic fields is perpendicular to the direction in which the waves travel, as well as perpendicular to one another. Since light waves oscillate in the transverse direction to the direction in which waves travel, light waves are also referred to as the transverse waves. Light’s electromagnetic energy is a kind of electromagnetic radiation. Light and such other radiation forms are composed of electric and magnetic forces that move in such a way that is similar to the waves produced when a pebble drips into water, but the waves in a pool are clumsy and slow which makes them incomparable to light whose speed of travelling is nearly 186,000 miles per second (“Electromagnetic Theory of Light”). Conclusion Study of light has been carried out continuously over the centuries. Various scientists including Newton, Huygens, Einstein, and Maxwell have proposed their theories of light. The prime focus of all these theories has been to explain the fundamental nature of light, what it is composed of, and why it exhibits the behaviors it does. While Newton defined light as composed of tiny particles, Huygens referred to the light as waves. Einstein suggested that light is composed of photons. This led to the evolution of quantum mechanics and a belief in the dual nature of light. Maxwell identified the electromagnetic nature of the light waves. Different theories have created a wide body of literature regarding the nature of light, and the knowledge has been used to both explain and utilize the behaviors of light in productive ways. Applications of light and optics include but are not limited to X-rays, and fiber optics. Works Cited: “Electromagnetic Theory of Light.” N.d. Web. 20 Dec. 2013. . “Newton’s Particle Theory of Light.” N.d. Web. 20 Dec. 2013. . “Theory of Light.” 2005. Web. 20 Dec. 2013. . The Electromagnetic Read More