Light: More Than Meets The Eye
Throughout the tapestry of human history, none has captured our collective imagination more than the profound enigma of light. This luminous entity has been the subject of enduring fascination. With questions as ancient as our existence, we have probed the very essence of light: its composition, its absence, and the way it bathes our world in its glow.
As we embark on this journey, we illuminate the mystique surrounding light, delving into its wave-like characteristics, navigating through the domains of interference and diffraction, and shedding light on the transformative practical applications that have expanded our cosmic comprehension.
In the 11th century, a medieval Muslim scientist named Alhazen conducted experiments on the light within a dark room. Along with experimentation, he provided mathematical proof that light travels in straight lines and follows the path that is easiest and quickest, a concept later identified as the main essence of Fermat's principle in 1662. (UNESCO, 2018). One of his most influential works, "The Book of Optics," later translated into Latin and continues to be a subject of study for academics and researchers, including scientific luminaries like Isaac Newton, Galileo Galilei, Johannes Kepler, and Christian Huygens during the scientific revolution and even to this day. (“Ibn Al-Haytham,” 2023)
Copyright © 2020 Islamic Self Help. All rights reserved https://islamicselfhelp.com/2020/03/14/ibn-al-haytham-and-the-productive-usage-of-time-when-stuck-at-home/
The hunt for the properties of light did not stop then. There were studies by people like Newton, who saw white light dispersing into seven constituent colors after passing through a prism, and Thomas Young, in 1880, through his Double Slit Experiment, unveiled the wave nature of light- which was identified by Maxwell as an electromagnetic wave. It has been the Russian nesting doll of researchers over time, and each time, it reveals itself differently. If we open the first mother doll of light, we see that it is not plain white but a combination of seven different colors [waves]. Each has its specific frequency. The rainbow is just the sunlight revealing its seven constituent colors after passing through the rainwater-which under normal conditions, remains hidden from our eyes.
(Image credit: art partner-images via Getty Images) https://www.livescience.com/50678-visible-light.html
Interference: Creating Patterns
Its wave nature is the reason why we see exquisite patterns in our daily lives, from a rainbow to random colors on a soap bubble. The focus here is the interference and patterns arising from it. Imagine you are at a calm lake on a sunny day, and you toss two small stones into the water, creating ripples that spread out. Now, picture what happens when those ripples from the two stones meet. When the peaks and troughs of the ripples align perfectly, they combine to create larger ripples. This is interference in nature, where two sets of waves come together and either strengthen or cancel each other out.
In the world of light, something similar happens. When light beams, like those from the sun or a flashlight, come together and their waves match up just right, they can create bright and colorful patterns. This is why you see rainbows, oil slicks, and the shimmering colors on soap bubbles. It is all thanks to the fascinating way light waves interact and create beautiful effects.
Therefore, interference is like nature's way of mixing and matching light waves to create something mesmerizing. It's why we see so many stunning colors in our everyday world, even if we haven't noticed the science behind it.
When sunlight, containing seven distinct colors, strikes a soap bubble or a wet surface, some of it reflects. These reflections interact, intensifying certain colors while diminishing others. This results in the striking array of colors you observe on soap bubbles or wet surfaces, resulting from the interplay between various light wavelengths. (Light and Color - Interference Phenomena in Soap Bubble, n.d.)
Soap bubble. (2024, January 5). In Wikipedia. https://en.wikipedia.org/wiki/Soap_bubble
Why is the sky blue?
Children, in their innate curiosity, often pose questions such as, 'Why is the sky blue? The answer to such questions also lies in the spectrum of white light. In scientific terms, it is due to ‘Rayleigh Scattering’, along with the non-linear perception of the human brain and eye. Rayleigh Scattering happens when light bounces off from an object that is much smaller than its wavelength. In Earth’s atmosphere, it is scattered by dust and gas particles like oxygen and nitrogen. But during this process, high frequency containing waves [colors] as blue and violet are much scattered when the sun is high in the sky. (Why Is the Sky Blue?, n.d.) Hence, it appears blue during daytime, although, during dusk and dawn hours, sunlight has to travel more to reach the surface, and by the time it arrives, most of the blue and violet colors are scattered, and only red and orange colors have lower frequencies are there, that is why it appears red. On cloudy evenings, it might appear pink or purple after passing through clouds due to the very same phenomenon (Why Is the Sunset Red? n.d.).
https://www.timeanddate.com/astronomy/red-sunset.html ©timeanddate.com
While some readers may find it exciting, few ask important questions such as, "What is the practical use of all this knowledge? Does it offer any benefits, or is it simply a tool of fascination for science geeks?".
Today, this knowledge manifests in real-life applications, benefitting society in multifaceted ways. Medical imaging, powered by the principles of light, aids in accurate diagnostics (Optics of Medical Imaging, n.d.). Fiber optic communication facilitates seamless global connectivity, while lasers revolutionize medical procedures (HOLIGHT, 2023). Solar cells harness the sun's energy for sustainable power, and LEDs contribute to energy-efficient lighting. Optical instruments extend our scientific reach, spectroscopy unravels chemical mysteries, and light therapy influences mental well-being. In realms of security and entertainment, light-based technologies safeguard and captivate. The intricate dance of light, as explored in this journey, not only enriches our understanding of the universe but also shapes the very fabric of our daily lives.
Works Cited
https://plus.google.com/+UNESCO. (2018, May 14). Ibn al-Haytham’s scientific method. UNESCO. https://en.unesco.org/courier/news-views-online/ibn-al-haytham-s-scientific-method
Ibn al-Haytham. (2023). In Wikipedia. https://en.wikipedia.org/w/index.php?title=Ibn_al-Haytham&oldid=117983959
Molecular Expressions Microscopy Primer: Light and Color—Interference Phenomena in Soap Bubbles: Interactive Java Tutorial. (n.d.). Retrieved October 28, 2023, from https://micro.magnet.fsu.edu/primer/java/interference/soapbubbles/index.html
Optics of Medical Imaging. (n.d.). Retrieved December 13, 2023, from https://spie.org/news/spie-professional-magazine-archive/2018-january/optics-of-medical-imaging
Posts—HOLIGHT Fiber Optic’s Latest Updates and Insights. (2023, January 7). https://holightoptic.com/optical-fiber/
Why is the sky blue? (n.d.). Science Questions with Surprising Answers. Retrieved October 30, 2023, from https://wtamu.edu/~cbaird/sq/2013/03/28/why-is-the-sky-blue/
Why is the sunset red? (n.d.). Met Office. Retrieved October 30, 2023, from https://www.metoffice.gov.uk/weather/learn-about/weather/optical-effects/why-is-the-sunset-red
