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Lesson 1 – What is Light?

Posted on: Monday, January 3rd, 2022  In: Learning Optics with Austin

Optics is the study of light. The root of the word “opt” relates to the eye and vision, while the suffix “ics” refers to a science or discipline. [1] With that enLIGHTenment, a discussion about optics is often a discussion about light, its behaviors, and its properties. One common starting point is to ask “What is light?” From our human experience, we encounter many different light sources such as the sun, light bulbs, or a campfire. These sources seem to not just give off light, but also heat. So what exactly IS light?

Sources of Light

As the old adage goes, “the simplest questions are often the most complicated to answer.” Ancient civilizations thought of light as rays falling through a forest canopy.

Rays of sunlight visible through the forest canopy

Fast forward into the future, Isaac Newton proposed that light was composed of particles. Newton’s contemporary, Christiaan Huygens, thought that light was composed of waves. Then the famous physicist Albert Einstein theorized that light was both a particle and a wave, forming the basis of the wave-particle duality. Light could be described as both an electromagnetic wave and as a photon, which is the extent of our current understanding of light.

Isaac Newton experiments with light

While optics is the bread and butter of companies like Shanghai Optics, the study of light explains many common phenomena in our lives. It helps answer some basic, but important questions like: “Why does the water in the ocean appear blue but becomes clear when you scoop it up? It all has to do with the absorption of light by water.

Different wavelengths of light (rainbow) over ocean waves

Why the sky is blue and how rainbows form have to do with the scattering of light. An education in optics can even help you take better photos by determining the “best angle” and lighting conditions in which to take the photo.


Next: Lesson 2 – How to Describe Light


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4 responses to “Lesson 1 – What is Light?”

  1. John says:

    Nice job!

  2. Yousef Ghasemzadeh says:

    Hi Austin
    Thank you very much for lessons!
    Is it possible to have these lessons in a downloadable form?
    Best Regards

    • Austin Wang says:

      Hi Yousef! Unfortunately, the lessons are only available on the website. I can discuss with the company about adding a downloadable PDF for each lesson if that would be helpful- let me know!


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