4.3+Introduction

=Unit 2 Optics=

Chapter 4 Many properties of light can be understood using a wave model of light.
4.3 Light and the Electromagnetic Spectrum


 * 4.3 Introduction** page 152


 * Invisible Waves**

Invisible waves are all around us. For example, a rainbow is a visible spectrum, it is a tiny portion of a larger spectrum of radiation called a electromagnetic spectrum. Some examples of these "waves" are the sun's rays, a wireless internet connection, the microwave, television and radio frequencies. You can not feel or see these waves but they are traveling through our bodies. These invisible "waves" are helpful for communication and can help humans in many ways.

__Chemical sunscreens__: protect the skin by obsorbing the ultraviolet waves. ||
 * **Questions:** || **Answers:** ||
 * What is a tiny portion of a much larger spectrum of radiation(the electromagnetic spectrem) called? || Electromagnetic spectrum. ||
 * What has shorter wavelengths, higher frequencies, and more energy than visible light? || Ultraviolet light, X rays, and gamma rays. ||
 * What has longer wavelengths, lower frequencies, and less energy than visible light? || Radio Waves and visible light. ||
 * Each region of the invisible spectrum has special properties that make it useful in some sort of ________? || Imaging tochnology. ||
 * Can you feel waves? || No ||
 * Can waves go through your body? || yes ||
 * Name 3 objects that use invisible waves || Sun waves, music waves, cellphone ||
 * How many types of sunscreen are there? || Tow types of sunscreen. ||
 * Name the types of sunscreen and what they do? || __Physical sunscreens__: protect the skin by reflecting the ultraviolet waves.
 * Can waves go through your body? || yes ||
 * Name 3 objects that use invisible waves || Sun waves, music waves, cellphone ||
 * How many types of sunscreen are there? || Tow types of sunscreen. ||
 * Name the types of sunscreen and what they do? || __Physical sunscreens__: protect the skin by reflecting the ultraviolet waves.
 * How many types of sunscreen are there? || Tow types of sunscreen. ||
 * Name the types of sunscreen and what they do? || __Physical sunscreens__: protect the skin by reflecting the ultraviolet waves.
 * Name the types of sunscreen and what they do? || __Physical sunscreens__: protect the skin by reflecting the ultraviolet waves.
 * Name the types of sunscreen and what they do? || __Physical sunscreens__: protect the skin by reflecting the ultraviolet waves.