Parabolic+Mirror+Applications

= What are Parabolic Mirrors? = toc Parabolic Mirrors are concave mirrors in the shape of a paraboloid of revolution. Parabolic mirrors have the ability to concentrate all energy reflected to one central or focal point. The process used to produce high-end parabolic mirrors can take months and cost thousands of dollars. = How it Works = The mirror works because of the geometric properties of the paraboloid shape. If the angle of incidence to the inner surface of the mirror is the same as the angle of reflection, then any incoming ray which is parallel to the principle axis of the mirror will be reflected to a focal point. Likewise, energy coming in from the focal point of the mirror to the surface will be reflected in a beam that’s parallel to the axis. =media type="youtube" key="UQrKtiKfmMU" width="425" height="350"= = Interesting Facts = = media type="youtube" key="wyXsYkumHcw" width="302" height="252" align="center"
 * One of the earliest uses of the parabolic mirror was in Isaac Newton’s reflecting telescope in the 17th century. By using a parabolic mirror, reflecting telescopes didn’t have as many aberrations as the older refracting telescopes. With the use of parabolic mirrors, however, some other problems are introduced. This includes a problem called coma, which exists in all telescopes using parabolic mirrors. Coma causes any objects viewed through the telescope which are not at the center of the field of vision to look slightly wedge-shaped. The further outside the field they are, the more distorted they appear.
 * During the world Olympics, the flame used for the Olympic torch is lit using a large parabolic mirror. This parabolic mirror collects sunlight and focuses it to a point to ignite the torch material
 * Who needs a stove? Here's how to make breakfast using a parabolic mirror.

= Car Headlights =

Car Headlights use parabolic mirrors as an effective way to provide maximum luminance on the road. Headlights have light bulbs placed on the focal point of the mirror. The incidence rays from the light bulb make their way to the surface of the mirror. Because of the light bulb’s position and the mirror’s parabolic shape, the refracted rays are all reflected parallel to the axis. This allows for the beams of light to all be directed up ahead of the car, making it brighter for the driver. This is also how spotlights and flashlights work. == = = = Light Polution = Light pollution is largely the result of bad lighting design, which allows artificial light to shine outward and upward into the sky.This excess lighting washes out the darkness of night and radically alters the light levels—and light rhythms—to which many forms of life, including ourselves, have adapted. Wherever human light spills into the natural world, some aspect of life—migration, reproduction, feeding—is affected.

Streetlights currently use convex mirrors, which send the incidence rays in every direction in order to light up larger areas; however, it's also causing excess aluminous in the atmosphere and blinding us from the night’s starry sky. The use of parabolic mirror would be very effective for this issue as it would send the light in a downward direction, rather than upwards and to the sides, where we don’t need it. This would be similar to the way car headlights work, by putting the light source in the focal and then reflecting all the rays off the mirror in a parallel manner. = = == = =

= Spoon Reflection =

Ever wondered why your reflection in the hallow side of a spoon is upside down? Well the answer that has baffled you for all of your childhood lies within a simple ray diagram. The hallow side of a spoon is an example of a concave mirror, hence resulting in a smaller, inverted, and real image - which is the reflection you see on the spoon. In the ray diagram, you are the object, and you are sending incident light rays to the surface of the mirror, which are being reflected as shown in the top of the bottom right ray diagram. As you can see, the incident rays coming in from the point of the object, are reflected in a way that would result in them meeting at a point below the principle axis, with a a shorter distance between the point and and the axis. This, again, is the result of the upside down reflection you see when you stare into a spoon. The opposite side of the spoon is a convex mirror, this side is no fun because the light rays produce an upright image as seen in the bottom ray diagram.



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= = = Glossary = = = = References = = = Kids.Net.Au - Encyclopedia > Parabolic mirror. (n.d.). //Kids.Net.Au - Encyclopedia//. Retrieved May 24, 2012, from http://encyclopedia.kids.net.au/page/pa/Parabolic_mirror Parabolic Mirror. (n.d.). //Universe Today â€” Space and astronomy news//. Retrieved May 24, 2012, from http://www.universetoday.com/44744/parabolic-mirror/ Parabolic Mirrors. (n.d.). //Encyclopedia//. Retrieved January 1, 2012, from http://encyclopedia.kids.net.au/page/pa/Paraboloid_of_revolution Parabolic reflector. (n.d.). //Encyclopedia//. Retrieved January 1, 2012, from http://encyclopedia.kids.net.au/page/pa/Paraboloid_of_revolution Physics 11.1.3a - Spherical and Parabolic Mirrors - YouTube. (n.d.). //YouTube - Broadcast Yourself.//. Retrieved May 24, 2012, from http://www.youtube.com/watch?v=UQrKtiKfmMU Syvum Physics Theory : Curved Mirrors & Reflection. (n.d.). //Syvum Homepage: Online Education, Interactive Learning and Homework Help//. Retrieved May 24, 2012, from http://www.syvum.com/cgi/online/serve.cgi/squizzes/physics/curved_mirrors.html?custom What is a Parabolic Mirror?. (n.d.). //innovateus.net | Innovation and information for sustainable living//. Retrieved May 24, 2012, from http://www.innovateus.net/science/what-parabolic-mirror What is a Parabolic Mirror?. (n.d.). //wiseGEEK: clear answers for common questions//. Retrieved May 24, 2012, from http://www.wisegeek.com/what-is-a-parabolic-mirror.htm it, I. h. (n.d.). APPhysicsB Blog. //APPhysicsB Blog//. Retrieved May 24, 2012, from http://shchau.wordpress.com/ = =
 * ** Angle of Incidence ** || The angle between an incident ray and the normal ||
 * ** Angle of Reflection ** || the angle between the reflective ray and the normal ||
 * ** Beam ** || a ray or shaft of light ||
 * ** Car Headlights ** || Two lights at the front of a car, providing a source of light to see at night ||
 * **Coma** || causes any objects viewed through the telescope which are not at the center of the field of vision to look slightly wedge-shaped ||
 * **Concave mirrors** || curved mirror is a mirror with a curved reflective surface bulging inwards ||
 * ** Convex Mirror ** || A curved mirror is a mirror with a curved reflective surface bulging outwards ||
 * **Focal point** || - The point on Principle Axis which reflected rays pass when the incident rays are parallel to the Principle Axis ||
 * ** Isaac Newton ** || English mathematician and physicist; remembered for developing the calculus and for his law of gravitation and his three laws of motion ||
 * **Light pollution** || Brightening of the night sky that inhibits the observation of stars and planets, caused by street lights and other man-made sources ||
 * ** Parabola ** || a form of curve, in which all points on the curve have the same focus ||
 * ** Paraboloid of Revolution ** || a three-dimensional figure formed by rotating a parabola about its axis of symmetry ||
 * **Principle Axis** || The line that is perpendicular to the mirror ||
 * **Reflecting Telescopes** || telescope in which a mirror is used to collect and focus light ||
 * **Refracting Telescopes** || A telescope that uses a converging lens to collect light ||
 * **Refracting Telescopes** || A telescope that uses a converging lens to collect light ||