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SECURITY MIRRORS AND SIDE VIEW MIRRORS

HOW DO CONVEX MIRRORS WORK?

Mirrors reflect light rays in order to produce an image which is what we see in the mirror. Security mirrors and car side view mirrors are both often convex mirrors, meaning they are curved outward. The concept of convex mirrors isn't hard to comprehend, but you first must understand how plane mirrors work. The reason we see things in plane mirrors is because the light rays strike the mirror and reflect back into our eyes. Your brain actually projects these light rays backward in a straight line when it detects light rays reflecting in a plane mirror. Your brain is tricked into thinking that there is a light source behind the mirror, which is actually false because the mirror is opaque. This imaginary light source is called an apparent light source. Convex mirrors are curved outward, resulting in the light rays reflecting off of the mirror, away from the light source. This makes it so that you can see a wider area when looking in a convex mirror, which has many applications such as security mirrors, car side view mirrors and more.
154500_528px-Convexmirror_raydiagram_svg_68.jpg
This diagram shows how rays work with a convex mirror to produce an image for the eye to see.
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WHY ARE SECURITY MIRRORS CONVEX?

The reason that security mirrors are often convex is beacause the light rays are diverging, making it possible to see more space than in a plane mirror. This would be very useful for security guards, because it allows them to see around corners a little bit. There is a video below showing how the rays diverge from the mirror, creating a greater viewing area. Security mirrors are also found in many convenience stores, with the idea of preventing thieves or teenagers from stealing. They are very useful for store owners, because they can look in the mirror and see over a range of a couple aisles, as oppose to just one aisle without the mirror.










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WHY ARE SIDE VIEW MIRRORS CONVEX?


Have you ever noticed this message on the side view mirror of a car?
OBJECTS_IN_MIRROR_ARE_CLOSER_THAN_THEY_APPEAR.jpg
'OBJECTS IN MIRROR ARE CLOSER THAN THEY APPEAR'

Have you ever wondered WHY it says this? There is a simple explanation for this warning on some car side view mirrors. It is because this mirror in convex, therefore distorting the image in the mirror. The reason that this mirror is convex is so the driver can see a wider area, helping them with their lane changes and reducing their blind spot. The mirror makes the cars behind the driver look a little bit smaller and farther away than they actually are, which is why the car manufacturer must put this warning on the mirrors.[3]

OTHER APPLICATIONS FOR CONVEX MIRRORS

These types of mirrors are also often found in underground parking garages. They are used to see around the corner to see if another car is coming down the ramp to enter the garage. Thanks to these convex mirrors, many accidents are prevented.
Garage_Mirror.jpg
Convex mirrors can be used to see around corners for drivers to see if another vehicle is in the driveway.
Christmas_bauble.jpg
This is a Christmas ornament displaying a virtual image because the object is between the focal point and the ornament.

CONCLUSION

Overall, a conclusion can be made that security mirrors and car side view mirrors are both used to see a wider area of space, therefore making it necessary for them to be convex. There are countless uses for convex mirrors, and they can be found almost anywhere we go. In general, the most common use for convex mirrors is safety; whether it is used to prevent car accidents, theft, or others.






GLOSSARY
  1. Principal axis - a line that passes through the centre of curvature of a lens so that light is neither reflected nor refracted.
  2. Centre of curvature - the very centre of a circle.
  3. Plane mirror - a mirror with a planar reflective surface. For light rays striking a plane mirror, the angle of reflection equals the angle of incidence.
  4. Convex mirror - a mirror whose surface is curved outward.
  5. Diverge - to extend in different directions from a common point.







  1. ^ Google Image Result for http://wikipremed.com/image_science_archive_68/010502_68/154500_528px-Convexmirror_raydiagram.svg_68.jpg. (n.d.). Google. Retrieved May 26, 2012, from http://www.google.ca/imgres?q=convex+mirror+ray+diagram&hl=en&biw=1600&bih=799&gbv=2&tbm=isch&tbnid=v4myOpjZzjNaWM:&imgrefurl=http:
  2. ^ Ray Diagrams - Convex Mirror - YouTube . (n.d.). YouTube - Broadcast Yourself. . Retrieved May 26, 2012, from http://www.youtube.com/watch?v=4zCm2KlcCR0&feature=player_embedded
  3. ^ Why does the passenger side window on my car state 'objects in mirror are closer than they appear?. (n.d.).PhysLink.com - Physics and Astronomy Online Portal. Retrieved May 26, 2012, from http://www.physlink.com/education/askexperts/ae449.cfm