GRADE 8: SCIENCE = ENERGY OF VISIBLE LIGHT.pptx

GRADE 8: SCIENCE = ENERGY OF VISIBLE LIGHT.pptx

• 1.
  ENERGY OF VISIBLE LIGHT
• 2.
  LIGHT • It isa kind of energy that can travel through space in a form of wave. Just like sound waves it can be reflected and refracted. It is a very small fraction of electromagnetic spectrum. • Light travels in straight line. • It looks white, but it is really a mixture of many colors. It is composed of colors of different frequencies and wavelength and the arrangement of colors of light shows the colors corresponding energy.
• 3.
  REFLECTION AND REFRACTION OFLIGHT • All waves are known to undergo reflection or the bouncing off of an obstacle. • All waves are known to undergo refraction when they pass from one medium to another medium. That is, when a wavefront crosses the boundary between two media, the direction that the wavefront is moving undergoes a sudden change; the path is "bent."
• 4.
  DISPERSION The separation ofvisible light into its different colors is known as dispersion. Each color is characteristic of a distinct wavelength; and different wavelengths of light waves will bend varying amounts upon passage through a prism. For these reasons, visible light is dispersed upon passage through a prism. Dispersion of visible light produces the colors red (R), orange (O), yellow (Y), green (G), blue (B), and violet (V).
• 6.
  • The shorterviolet and blue wavelengths in the spectrum scatter away from the human field of vision. However, the longer yellow, orange, and red wavelengths of light do not scatter as much. Thus, the sky takes a yellow, orange, and red palette. • Though the atmospheric particles scatter violet more than blue the sky appears blue, because our eyes are more sensitive to blue light and because some of the violet light is absorbed in the upper atmosphere. • You might wonder where ‘pink’ came, as pink isn’t a wavelength in the visible spectrum; its appearance is caused solely by the mixing of red with white.