Color and Refraction

The Electromagnetic Spectrum

  • The electromagnetic spectrum includes various types of electromagnetic radiation, with visible light being a small portion.

  • The visible spectrum consists of the colors recognized by the human eye.

  • The sequence of visible colors is remembered with the mnemonic ROYGBIV:

    • Red

    • Orange

    • Yellow

    • Green

    • Blue

    • Indigo

    • Violet

  • This sequence lists colors from lowest frequency (red) to highest frequency (violet).

Color Perception

  • Objects appear colored depending on the light they reflect and absorb.

  • Illumination results in:

    • Absorption: Some wavelengths absorbed by the material.

    • Reflection: Remaining wavelengths are reflected and seen.

  • Example: A green leaf reflects predominantly green light while absorbing other colors.

  • Completely absorbing all visible wavelengths results in a black appearance; reflecting all wavelengths under illumination results in a color matching the light source.

Reflection of Light

  • When light hits a reflective surface:

    • The angle of incidence (incoming angle) equals the angle of reflection (outgoing angle).

    • These angles are measured with respect to a vertical line perpendicular to the surface.

Refraction of Light

  • Light changes direction when traveling through different media (e.g., air to water), a process called refraction:

    • Example: Light travels slower in water than in air, causing visual distortion, making objects appear closer.

  • If light travels from one medium to another, the angle changes as follows:

    • The angle of incidence differs from the angle of refraction (the new angle of direction).

Prisms and Dispersion

  • A prism can separate white light into a spectrum of colors due to refraction:

    • Different wavelengths are slowed down by different degrees, resulting in distinct angles of refraction.

  • White light can be produced by combining the three additive primary colors:

    • Red

    • Green

    • Blue

  • Mixing light through colored filters:

    • Red + Green = Yellow

    • Adding Blue = White Light

    • Yellow is the complementary color of Blue.

Color Receptors and Art

  • Human eyes have three types of color receptors sensitive to red, green, and blue, stimulating various combinations.

  • Art materials (e.g., paints) exhibit colors based on light reflection, which differs from pure light beams:

    • Mixing paints results in color subtraction.

    • Blue + Yellow Paint = Green.

  • Subtractive primary colors: Cyan, Magenta, and Yellow:

    • Combined, these absorb all colors from white light, resulting in a black appearance.

Conclusion

  • Understanding the electromagnetic spectrum and the properties of light enhances appreciation for colors found in art and nature (e.g., rainbows).

  • For deeper knowledge, seek additional resources or support learning through subscriptions and patron-based content.