refraction

• What happens to light as it passes through water?

  It appears to change direction
• Why do waves change direction when they change speed?

  Due to moving from one medium to another
• How can refraction be illustrated?

  With a ray diagram
• What happens to light waves when they enter glass from air?

  Their velocity decreases
• What does the normal line represent in a ray diagram?

  It is at right angles to the surface
• What occurs when waves slow down as they enter a medium?

  They bend towards the normal
• What happens when light waves pass from glass back to air?

  Their velocity increases
• What is the effect of waves speeding up when leaving a medium?

  They 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
• What is a wavefront?

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

  They show lots of waves moving together
• What happens to wavefronts when they enter a new medium?

  Parts of the wavefront slow down
• What occurs to the wavelength as wavefronts slow down?

  The wavelength gets smaller
• What is the result of wavefronts getting closer together?

  Waves change direction towards the normal
• What happens when wavefronts approach along the normal?

  The whole wavefront slows down simultaneously
• What is the key concept of refraction?

  Waves change direction when speed changes
• What are the key facts about refraction?

  • Waves can change direction when speed changes
  • Refraction occurs when waves move from one medium to another
  • Waves bend towards the normal when slowing down
  • Waves bend away from the normal when speeding up
  • No change in direction occurs when entering at right angles
• What are the characteristics of wavefronts?

  • Imaginary lines connecting points in waves
  • Can connect peaks or troughs of waves
  • Help visualize multiple waves moving together
• What is the relationship between wavefronts and refraction?

  • Parts of wavefronts slow down in a new medium
  • Wavelength decreases as wavefronts slow down
  • Wavefronts getting closer together causes direction change
  • Whole wavefronts slow down when approaching along the normal