Light and Shadows

KEY IDEAS

  • Light travels outwards from its source
  • Some materials let light pass through them, others do not
  • Light cannot pass through opaque materials
  • Shadows are formed by opaque materials blocking out the light path

EXAMPLE QUESTIONS

  • What kind of materials make shadows?
  • What kind of materials do not make shadows?
  • What has to happen for a shadow to be made?

LIGHT CAN PASS THROUGH CERTAIN MATERIALS

  • Materials, such as clear glass or perspex, clingfilm and clear water, let most of the light pass through them.
  • Some materials, such as colored glass, only let certain colors of light pass through them.
  • Opaque materials, that have no transparent quality, such as wood, do not let any light pass through them.

SHADOWS CAN FORM BEHIND OPAQUE OBJECTS

  • Opaque objects block out the light by absorbing it. As a result, a shadow may form behind the object.
  • This is because light travels in straight lines from its source.
  • It cannot wrap around the opaque object to illuminate the area behind it.