Notes on Rainbows and Visible Light

Introduction to Rainbows

• Almost everyone loves a rainbow.
• Rainbows are an example of visible light.

Understanding Visible Light

• Definition: Visible light is a narrow range of wavelengths and frequencies within the electromagnetic spectrum.
• Position in Spectrum: Found between infrared waves and ultraviolet waves.
• Wavelength Range: Approximately 400 to 700 nanometers.

White Light

• What is White Light?: The combination of all visible wavelengths.
• Sources of White Light: Sunlight and light bulbs.
• White Light and Prisms: Passing white light through a prism reveals different colors.

Historical Context

• Sir Isaac Newton: Described white light as consisting of different colors in 1671 in his book "Optics".

Colors of Visible Light

• Mnemonic for Colors: Use "ROY G. BIV" to remember the colors:
  • Red
  • Orange
  • Yellow
  • Green
  • Blue
  • Indigo
  • Violet
• Wavelengths of Colors:
  • Red: Lower end of spectrum (longer wavelength ~740 nm)
  • Green: Middle of spectrum
  • Violet: Upper end of spectrum (shorter wavelength ~380 nm)

Pure Colors

• Definition: Colors that contain only one wavelength, specifically red, green, and blue.
• Color Mixing: All other perceived colors result from mixtures of these pure colors.

Light Properties

• Frequency and Photon Energy:
  • Red Light: Lowest frequency and photon energy; longest wavelength.
  • Violet Light: Highest frequency and photon energy; shortest wavelength.

Summary Chart

• Chart includes a summary of wavelength, frequency, and photon energy for different colors.

Conclusion

• Remember: "Kindness multiplies kindness."