LIGHT-PHENOMENA

Light Phenomena Overview

  • Light is an electromagnetic wave traveling at 186,282 miles per second.

  • Various phenomena associated with light are discussed, including reflections, mirages, and rainbows.

Objectives of Study

  • To explain various light phenomena such as:

    • Reflection on concave and convex sides of a spoon.

    • The occurrence of mirages.

    • Light passing through colored cellophane.

    • Color perception of clothing under different lighting conditions.

    • Optical phenomena including halos, sundogs, primary and secondary rainbows, and supernumerary bows.

    • Reasons for the color of clouds and the sky and the appearance of sunsets.

Reflection on Concave and Convex Surfaces

  • Concave Side:

    • Reflection appears upside down and smaller.

  • Convex Side:

    • Reflection appears right-side up and larger.

  • Curved mirrors create distinct reflections due to the way light reflects off their surfaces.

Mirages

  • Occur due to refraction of light by temperature gradients in the air.

  • Create optical illusions of objects being closer or further away, commonly seen in deserts.

  • More frequent on sunny days, resulting in illusions like water on the roadway.

Light and Color

  • Red Laser and Cellophane:

    • Red light passes more easily through red cellophane compared to green due to wavelength absorption.

  • Color Filters:

    • Red and green filters only allow their respective colors to pass, demonstrating color by subtraction.

Clothing Colors in Different Lights

  • Certain colors appear different under artificial light (like LEDs) versus natural sunlight.

  • Natural light contains a full spectrum of colors, while artificial light sources may not have UV light crucial for color fluorescence.

  • Clothes appear differently due to this variation in light sources.

Optical Phenomena: Halos and Rainbows

  • Halos and Sundogs:

    • Occur due to the refraction of light through ice crystals in the atmosphere.

    • Halos are rings around the sun or moon, harmonized by ice crystals.

  • Rainbows:

    • Formed by reflection, refraction, and dispersion of light in water droplets.

    • Primary and Secondary Rainbows:

      • Primary: One internal reflection and two refractions.

      • Secondary: Two internal reflections, generally fainter and positioned outside primary rainbow.

    • Supernumerary Rainbows:

      • Additional faint bows inside primary bow, displaying pastel colors.

Cloud Coloration

  • White Clouds:

    • Clouds reflect and scatter all sunlight colors, appearing white.

  • Rain Clouds:

    • Dark appearance due to density, absorbing more light, making them appear darker than regular clouds.

Sky Coloration

  • Blue Sky:

    • Sky appears blue due to scattering of shorter wavelength blue light by the atmosphere.

  • Sunsets:

    • At sunset, light's longer path scatters colors differently, creating reddish-orange hues.

Conclusion

  • The study of light and its phenomena enriches our understanding and appreciation of the visual world around us.

References

  • Hyperphysics. (n.d.). Reflection: Concave and Convex Mirrors.

  • Livescience. (2013, August 27). What Causes Mirages?

  • Science Learning Hub. (n.d.). Colour and Light.

  • The Royal Society of Chemistry. (n.d.). Why are clouds white but rain clouds dark?

  • Universe Today. (2018, January 3). Why is the Sky Blue?