Refraction of Waves

• What happens to light as it passes through water?

  It appears to change direction due to refraction
• What is a key fact about refraction?

  Waves change direction when changing speed
• How does light behave when it enters a glass block from air?

  It slows down and bends towards the normal
• What does the normal represent in a ray diagram?

  A line at right angles to the surface
• What happens to light waves when they pass from glass back to air?

  They speed up and bend away from the normal
• What can cause the image of an object to appear shifted?

  Refraction of light waves
• When does refraction not occur?

  When waves enter at right angles to the surface
• What is a wavefront?

  An imaginary line connecting points in waves
• How do wavefronts help visualize waves?

  They connect identical points in a set of waves
• What happens to wavefronts when they enter a new medium?

  Parts of the wavefront slow down and get closer
• What causes waves to change direction towards the normal?

  When parts of the wavefront slow down
• What happens when waves approach along the normal?

  The whole wavefront slows down without changing direction