Waves travel in mediums and like that one person who can't decide what to order at a restaurant, they sometimes can't decide what to do when they hit a boundary!

• Reflection: Think of a bouncy ball! The wave bounces back into its original medium, keeping its speed.
  • Real-world example: When you look in a mirror, the light waves from objects bounce back to your eyes. That's reflection!
• Transmission: Like a guest entering a new house, part or all of the wave enters the new medium beyond the boundary, often changing its speed.
  • Real-world example: Wear glasses or sunglasses? When light goes through the lenses, that's transmission!

Which one happens? Wave speeds are the bouncers deciding whether waves get reflected or transmitted. 🚦

When a wave moves from one medium to another, it's like a car shifting gears. The wave's speed often changes.

• Effect on Water Wave
  • Picture a beach! 🏖️ Waves come ashore and their speed and appearance change as they move from deep to shallow water.
  • In Figure 5, the waves are:
• Heading towards a metal strip that's pretending to be a mirror (Reflection).
• Moving from deep to shallow water (Transmission).

Key Takeaways from Figure 5

• (a) Mirror Moment
  • Wave hits the metal strip and no change in wavelength (distance between wave peaks).
  • Ever seen how the angle you throw a ball at a wall equals the angle it bounces back? Same here! Angle of incidence (i) = Angle of reflection (r). These angles are measured using the "normal", an imaginary line at 90° to the mirror.
• (b) Shallow Shenanigans
  • Wave moves to shallower water and slows down because of the base friction of the tank. Two major changes
• Wave gets a bit squished. Wavelength shortens in the shallower water.
• Wave takes a slight detour and bends at the interface. This bendy behavior is called refraction.