Reflection, Refraction, Burning Cars, and Survival Skills

We’re having one SIZZLING summer over here at Allied Eye!

In the spirit of this heat wave, we’re turning lemons into lemonade by highlighting the unique learning experience we had at the office yesterday!  

Yes. This is in our staff parking lot.

Let us tell you… We were handed some very big, very juicy lemons.  Here’s what we suspect happened:

Dr. Matzkin had a concave mirror sitting in the back seat of his car – like the curved mirrors used for applying makeup. Sunlight streaming through the window reflected off the mirror, formed a concentrated hot spot, and ignited the interior of his car. Think of the way you can use a magnifying glass to set leaves ablaze.

Example of a convex mirror focusing the sun's rays onto a smoldering object.

How, you may ask, is this an interesting example of eye-related processes?  The irony here is that Dr. Matzkin basically employs this principle every day when making refractive corrections to our patients’ vision.

In fact, the WAY YOU SEE is a result of this phenomenon: light bends when it enters your eye and focuses itself on your retina. By changing the shape of your lens (cataract surgery, contacts, glasses, LASIK are all examples), that beam of light becomes MORE focused, and it produces a clearer image when it reaches the back of your eye. 

Convex REFRACTION (Lens of the Eye)

The way light bends and curves when it passes through a substance is called refraction. When it bounces off a surface, that’s reflection. With a more perfect lens comes a more perfect focal point, and with that comes more perfect vision.  

Concave REFLECTION (Mirror and Flaming car)

For our purposes, we will call these tools “burning mirrors” and “burning lenses” when they are used to create fires.

The earliest lens artifact, discovered from the 7th century BCE in ancient Assyria may have been used as a burning lens. The earliest record of “burning mirrors” comes to us from the Greek mathematician, Diocles, in the 3rd Century BCE (Consider that the lens was not modified for use in cataract surgery until the 1950s).

Burning lenses have been used historically to cauterize wounds and to light sacred fires in temples (the eternal Olympic Flame, for example). During the French Revolution, the French government considered developing the burning lens into a weapon that would ignite British Ships from afar. In the 18th century, burning lenses became popular for use in chemical experiments. 

Not All burning glass ideas are brilliant, as you may have assumed by the first photo in this entry… In a 1920’s book by William Bates, the author argues that vision can be perfected by "Focusing the Rays of the Sun Upon the Eye of a Patient by Means of a Burning Glass.” Needless to say, this is highly dangerous and will damage the eye in seconds.

Today, burning lenses and mirrors have plenty of practical applications, like headlights, lighthouses, and solar stoves.