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OVERVIEW. In The Biology of Skin Color, Penn State University anthropologist Dr. Nina Jablonski walks us through the evidence that the different shades of human skin color are evolutionary adaptations to the varying intensity of ultraviolet (UV) radiation in different parts of the world.
The manner in which visible light interacts with an object is dependent upon the frequency of the light and the nature of the atoms of the object. In this section of Lesson 2 we will discuss how and why light of certain frequencies can be selectively absorbed, reflected or transmitted.
Demonstrate reflection of light using a metal spoon and show how curved surfaces differ in the images they reflect. Demonstrate refraction of light as it travels from air into water using a laser pointer and a container of water.
Based on this new information, revise your hypothesis to explain the selective pressure on the evolution of human skin color. The greater amount of eumelanin in darker skin protects folate from being broken down by UV radiation and thus increases fitness among populations in high-intensity UV areas. 17.
describe how the selective absorption of frequencies of light affects the observed color of an object, describe how the selective reflection of frequencies of light affects the observed color of an object, rank the wavelengths of light waves that correspond to different colors of light.
Light reflects from a smooth surface at the same angle as it hits the surface. For a smooth surface, reflected light rays travel in the same direction. This is called specular reflection. For a rough surface, reflected light rays scatter in all directions. This is called diffuse reflection.
Reflection and refraction questions. Refractive index and the speed of light. Refraction and light bending. Why do stars twinkle (but planets don't)?
