Waves: Definition, Behavior, and Classification PDF

Waves **Definition, Behavior,** **and Classification** 2002, Den Russell **What\'s the underlying theme?** **What is a wave?** ***WAVE*** - a vibration or disturbance in space. **What is a wave?** **Waves *transfer energy* without transferring matter**. **How are waves classified?** **Wav...

Waves **Definition, Behavior,** **and Classification** 2002, Den Russell **What\'s the underlying theme?** **What is a wave?** ***WAVE*** - a vibration or disturbance in space. **What is a wave?** **Waves *transfer energy* without transferring matter**. **How are waves classified?** **Waves are classified by *WHAT* they move through or by** HOW **particles move through them.** **What material do waves move through?** ***MEDIUM-*** the substance that waves travel through and need to have in order to move. **Classification of Waves** According to what they move through (Medium) Electromagnetic waves Mechanical Waves **Electromagnetic Waves** Waves that can travel through matter or empty space where matter is not present. *The Electromagnetic* Spectrum 104cm 14 www Microwave Camma ray Ultraviolet Visible Radio X-ray Infrared **Types of Electromagnetic** **Waves** radio waves microwaves infrared waves visible light ** ** ultraviolet rays X-rays **Mechanical Waves** Needs a medium require the particles of the medium to vibrate in order for energy to be transferred. **Types of Mechanical Waves** water waves earthquake/seismic waves sound waves waves that travel down a rope or spring **Classification of Waves** According to how particles move through them Transverse waves Longitudinal Waves **Transverse Waves** Particles move ***perpendicular*** to the motion of the wave T Wavelength Amplitude Trough Crest ***Wavelength (λ)*** The *distance* from crest to crest (or trough to trough)**;** expressed in meters ***Amplitude (A**)* The distance of crest (or trough) from the *midpoint* of the wave **Longitudinal Waves** particles move ***parallel*** to the motion of the wave. **Longitudinal Waves** ***Compression-*** a crowded area causing a high- pressure region ***Rarefaction-*** a spread out area causing a low- pressure region Rarefaction *-Compression* http://www.lcse.umn.edu/specs/labs/glossary\_items/rarefaction\_spring.html Transverse and Longitudinal Wave Which is which? ( l l l l l l l l l l l l l l l l l l l l l WAVELENGTH **Wave Characteristics** ***Frequency (f)*** The number of waves that passed a fixed point per second **Unit:** *hertz (Hz)* f= 1T* **Wave Behaviour** What happens when\... A wave meets a hard surface like a wall? A wave enters a new medium? A wave moves around an obstacle? A wave meets another wave? **Reflection** When a wave hits a surface through which it cannot pass, it bounces back. **Reflection** Reflection does not change the speed or frequency of the wave*, **BUT*** the wave can be flipped upside down! **Refraction** The bending of a wave as it enters a new medium. It is caused by a change in the speed of the wave as it moves from one medium to another Greater change in speed = [more] bending of the wave **Diffraction** The bending of a wave as it moves around an obstacle or passes through a narrow opening. **Diffraction** The wave will try to curve around the boundary or outward through the opening due to friction. **Interference** When two or more waves *combine together.* Wave Interaction **Constructive Interference** = АА When two waves combine to make a larger wave. (crest & crest) or (trough & trough) **Destructive Interference** \+ \|\| Two or more waves combine to produce a smaller wave or destroy the wave completely. (crest & trough) **Polarization** Filtering radiating light (moves in all directions) to allow only light traveling in one direction through **Polarization** Nonpolarized light vibrates in all directions Horizontal and vertical components Vertical component passes through first polarizer\... \...And the second \*\* Vertical component does not pass through this second polarizer THE THE Hewitt, Conceptual Physics, Ninth Edition Copyright © 2002 Pearson Education, Inc., publishing as Addison Wesley. All rights reserved. **Resonance** When one object vibrates another without touching The 2 objects resonate at the same frequency Amplitude increases Fork A resonates **Resonance** Fork B begins resonating with sympathetic vibrations TELIL