Light

• Light


  Travels as a transverse wave
• Visible light


  The light that we detect with our eyes
• How we see an object

  1. Light from the sun travels to the object

  2. Light is reflected off the object

  3. Light enters our eye
• There are no particles in space, it is a vacuum
• Unlike sound, light does not need particles to travel, therefore light can travel through space
• Light travels much faster than sound, at 300 million meters per second
• It takes approximately eight minutes for light to travel the 150 kilometers from the sun to earth
• Luminous objects


  Objects that emit light, e.g. the sun and light bulbs
• Non-luminous objects


  Objects that do not emit light, e.g. footballs, books, and apples
• We can see non-luminous objects when light reflects off of them and into our eyes
• Transmit light


  When light can go through objects
• Transparent objects


  • Transmit most of the light that hits them, e.g. glass
• Translucent objects


  • Transmit some light but scatter it, so you don't see a clear image, e.g. frosted glass
• Opaque objects


  Do not transmit light, most of the light that hits them is absorbed and some is reflected
• Most objects are non-luminous, but we can see them when light reflects off of them and into our eyes
• Light can travel through gases, liquids, and some solids