Wave Interactions Reflection return of a wave when

Wave Interactions

Reflection return of a wave when it reaches a boundary of a medium

2 Types of Reflection: Fixed Boundary: the reflected wave is inverted when it reflects from a more dense medium Free Boundary: the reflected wave is not inverted when it reflects from a less dense medium

Reflection: Free vs. Fixed boundary

Refraction • bending of a wave passing from one medium into another • Wave changes speed For refraction to occur, the wave must change speed and must enter the new medium at an angle.

Refraction: Why waves always go into the shore

Diffraction the spreading of a wave around a barrier or through an opening

Island vs. Pillar Diffraction & Reflection

Interference • Two or more waves passing through the same location at the same time. • Also called: superposition Superposition Principle The total displacement due to interference is the sum of the displacements of the individual waves

Types of Interference Constructive results in a larger amplitude Destructive results in a smaller amplitude

Chapter 14 Section 3 Wave Interference Video

Interference Application • Destructive interference used for our benefit • Noise Cancellation Technology – Cars – Headphones – Dentist Drills – Factories

Resonance: Large amplitude waves caused when the frequency of an applied force is equal to the natural frequency of an object. Video Examples: • • • Wine Glass Rice Ruben's Tube Tesla Coils & More Tesla Coils Suspension Bridge with Harmonics Washington Tacoma Bridge & Real Explanation

Doppler Effect the change in frequency due to the relative motion of the wave source and the observer The observed frequency is higher when the source and observer are getting closer. The observed frequency is lower when the source and observer are getting farther away.

Click here and here to run simulations of the Doppler Effect. The Doppler Effect can be evident for ALL types of waves – including light, sound, water, etc…

Big Bang Theory. Doppler Effect