Overview
This lecture discussed the properties of visible light, the hierarchy of colors in terms of wavelength, frequency, and energy, and how light bends through refraction and dispersion. Key concepts included the visible spectrum (ROYGBIV), the behavior of light through prisms, and factors affecting wave speed and bending.
Recap: Sound and Light Fundamentals
- Sound is caused by vibrations traveling in waves through solids, liquids, or gases.
- Sound travels faster in solids due to closely packed molecules.
- Temperature increases sound speed by energizing molecules.
Colors of Light
- Light is a form of energy called radiant energy, traveling as electromagnetic (EM) waves.
- White light (sunlight) is a mix of different colors, visible as ROYGBIV: Red, Orange, Yellow, Green, Blue, Indigo, Violet.
- The color we see from objects is the reflected color from white light.
Spectrum, Prism, and Dispersion
- A prism is a transparent object that separates white light into its color components by bending (refracting) the light.
- The separation of colors is called dispersion, resulting in a spectrum.
- The atmosphere acts as a natural prism, creating rainbows.
Hierarchy of Colors: Wavelength, Frequency & Energy
- Colors are arranged by wavelength, frequency, and energy: red has the longest wavelength/lowest frequency and energy; violet has the shortest wavelength/highest frequency and energy.
- Higher frequency means greater energy; lower frequency means less energy.
- Wavelength is the distance between two wave peaks; measured in nanometers (nm).
- Red has the least energy and is least bent; violet has the most energy and is most bent.
Bending of Light (Refraction)
- Refraction is the bending of light as it passes through different media (air, water, glass, etc.).
- Degree of bending depends on optical density and wavelength; shorter wavelengths bend more.
- The index of refraction measures how much light bends in a medium.
- Red bends the least; violet bends the most.
Key Terms & Definitions
- Radiant energy — energy carried by light, also called electromagnetic energy.
- White light — visible light composed of all colors in the spectrum.
- Prism — transparent object that refracts and disperses light into a spectrum.
- Dispersion — separation of white light into colors by refraction.
- Spectrum — the range of separated colors produced when white light is dispersed.
- Wavelength — distance between successive points of a wave (measured in nm).
- Frequency — number of wave cycles per second (measured in hertz, Hz).
- Refraction — bending of light as it passes from one medium to another.
- Index of refraction — measure of how much light bends in a specific medium.
Action Items / Next Steps
- Complete module activities: observe illustrations and answer related questions on color bending and refraction.
- Review the ROYGBIV color sequence and learn to identify which colors have higher/lower wavelength, frequency, and energy.
- Prepare for next week's topic: Heat and Temperature.