Refract Light Rays example essay topic

Light is a kind of electromagnetic radiation. It is made up of vibrations between a certain group of frequencies. When light is given off from a source it spreads out over a larger area. Scientists are still dumbfounded by exactly what light is. When light hits a smooth or polished surface it 'bounces' off at the same angle that it hit. Reflecting telescopes are made of concave mirrors and they have helped astronomers chart the universe because the mirrors interact with each other to magnify what is being observed.

Refraction is when light bends as it goes through glass, water and other transparent objects that are denser than air. A prism is an instrument that spreads out a ray of light into the color spectrum. A lens is another instrument that uses the light refraction, but lenses are put to more practical uses (I'm not saying that a mirror isn't practical enough. ). Welcome to the wonderful world of light, including the refraction and reflection of light. Refraction is the bending of light when it travels through a denser, or thicker material, such as water.

Reflection is a bit different though; when light hits a smooth or polished surface it 'bounces' off the surface at almost the same angle (Depending on how flat the surface is. ). But before we get onto that, lets talk about light and exactly what it is. THE NATURE OF LIGHT Light is a kind of electromagnetic radiation, which means, that they are magnetic waves and particles which are caused by electricity. Light consists of very fast oscillations at a certain group of frequencies, that can be detected by the human eye. When light vibrates at different frequencies the eye sees different colors.

When light is emitted, or given off, from a source such as the sun, it moves in straight lines, and starts to filter out into a broader area as it travels farther. If it is interrupted by an object it will have an alteration in its course. Many Physicists as well as scientists are still puzzled by the nature of light. Sir Isaac Newton, an English physicist and mathematician, thought light of as a series of particles, because it was apparent that light moved in a straight line. To explain refraction and reflection he believed that the light particles, called photons, were in fact drawn to denser materials such as water and glass. Another way light acts as particles is that atoms absorb photons and are given energy.

Then the excited atom gives off another photon in return for the photon that it was given. The Dutch mathematician, astronomer, and physicist, Christiaan Huygens countered Newton with the wave theory. He figured he could prove Newton wrong because if photons were drawn towards water and other dense materials, its velocity would become greater because the force of being pulled would speed it up. And it was proven that light slowed down when it went through such materials.

But Huygens still couldn't explain how a light wave could give atoms energy, or how photons couldn't. Now scientists believe that the two theories complement each other. As a result the quantum theory came into being. The quantum theory says that in some ways light acts as a series of particles and in other ways acts as a wave.

The French physicist Armand Hippolyte Louis Fizeau was the first person to successfully measure the speed of light. The speed of light is 186,282.396 miles per second in a vacuum such as space. The speed of light is 3% less in air than in a vacuum; water is about 25 percent less, and in glass is 33%. Reflection As discussed at the beginning: when light hits a flat, smooth / polished surface it 'bounces' back at the same angle that it hit. The ray that the light hits such a surface, say a mirror, is called the incident ray. The light is reflected at the same angle that it hit, if it is flat enough.

We call the angle that the incident ray hits, the angle of incidence. The angle is determined from the angle of the incident ray to the normal. The normal is an imaginary line, like the equator, that is perpendicular to the object that the incident ray hits (see Fig. 1). The angle that the light is reflected is the angle of reflection. Obviously then the light ray that is reflected is called the reflected ray. The angle of reflection is the angle between the reflected ray and the normal, just like the angle of incidence.

When the light from an object is reflected off a plane (flat) mirror the image of the object, say an apple, appears to be behind the mirror at the same distance and angle as the distance and angle from the object to the mirror, as shown in Fig. 2. Refraction Refraction is the bending of light as it moves through a denser material. The reason why light bends like this is because the velocity of light slows down as it travels through a denser material than it was already in. To a person looking at an object in a denser material than that person is in, the object looks closer to the surface of the denser material than it actually is. A good example would be a person standing on the shore of a pond, looking down at an object underwater (Fig. 3.

). The light ray DB from object D is bent away from the normal, towards person A, because it is traveling into a less dense material. Therefore object D seems to be lying at image C, because a straight ray would be ABC, and that is the one you see. A prism is a flat, triangular piece of glass.

When light passes through a prism the incident ray is refracted, but in a special way. A prism can spread out the different colors of light when it passes through the prism (Fig. 4). So then the exit ray is in fact many different colored rays of the spectrum (All the colors of the rainbow. ). Lenses refract rays as well. Lenses are pieces of glass that are made curved in or curved out so that the refracted rays are put to use and are focused.

Lenses that are curved in are called concave lenses (Fig. 5), and lenses that are curved out are called convex lenses (Fig. 6). There are many other kinds of lenses, but these are the two basic ones. Lenses are put to many good uses such as refracting telescopes (Reflecting telescopes have concave mirrors), glasses, magnifier's, microscopes, and many other important things that we use in our every day lives. Light pays an important role in everyone's lives, basically we couldn't see without it; but it has also confused many scientists and physicists whether light is a wave or a particle.

Light travels in a straight line and spreads out over a larger area, but if it is interrupted by something its course changes. One thing that can change the direction of light is a hard, polished surface, such as a mirror. When a light hits a mirror it 'bounces' off it at the same angle that it hit, if the mirror is flat (which most are). Another thing that can interrupt the travel of a light ray is a denser material than it was already in. This is called refraction, which is the bending of light. Prisms and lenses are pieces of glass that are specially designed to refract light rays and put them to use.

Light can be mysterious in many ways, but in other ways it can be useful. bibliography Encyclopedia Britannica 1989.