Science Unit 6a Page 2

• One property of light is that it travels in straight lines, called rays
• Shadows prove that light travels in straight lines; when an opaque object blocks its way, light does not go around it but instead forms a shadow
• An everyday example of the application of light traveling in straight lines is the construction and use of a pinhole camera
• Transparent materials are things that allow light to pass through them easily, like glass and clear plastic
• Reflection of light: when light strikes any surface, it is reflected; smooth surfaces like mirrors, metals, and plastics reflect light well
• Opaque materials are things through which light cannot pass, like steel, wood, and rock