science

• Light


  • Always travels from a source
  • Always travels in a straight line
• Primary light source


  Creates its own light
• Secondary light source


  Reflects light from a primary light source
• Shadow

  The absence of light when it cannot pass through an opaque object
• Types of materials

  • Transparent - lets lots of light through
  • Translucent - lets some light through
  • Opaque - lets no light through
• How we see things

  1. Light travels from source in straight lines

  2. Light reflects off objects and bounces into our eyes through pupils

  3. Lens focuses light onto retina (upside down image)

  4. Retina changes light into nerve signals sent to brain

  5. Brain flips image 180 degrees
• Angle of incidence

  The angle that light hits a reflective surface
• Angle of reflection


  The angle that light changes direction when it reflects off a surface
• Angle of incidence


  Equal to angle of reflection
• Surfaces that do not reflect well absorb lots of light
• Object closer to light source

  Larger shadow
• Object further from light source


  Smaller shadow
• Refraction


  When light travels at different speeds through transparent materials, causing it to bend
• Refraction causes objects to seem distorted when in water or glass
• Visible spectrum


  The 7 colours of the rainbow that make up white light
• How a prism separates white light

  1. White light slows when entering prism at an angle

  2. Each wavelength (colour) refracts at a slightly different angle

  3. Light disperses and separates into 7 colours
• When all 7 colours of the visible spectrum merge together, they look white