Wave Properties & E-M Spectrum

Sound and Light

Wave Basics

Key Vocab.-Amplitude: The maximum displacement of a wave from equillibrium (height of a wave)-Wavelength: The length of one full wave cycle or repetition -Period: The amount of time it takes a wave to complete one full cycle-Frequency: The number of wave vibrations/repetitions per second (Hz)-Equilibrium: The resting place of a wave with no disturbance-Crest: The highest point or peak of a wave-Trough: The lowest point or bottom of a wave

Crest

Trough

Line of Equilibrium

Wave Types• A wave is a traveling disturbance that transfers energy.

• 2 Types of Waves:– Transverse: side to side wave sending vibration perpendicular to

the medium

– Longitudinal: push & pull wave sending vibration parallel to the medium

Parallel Vibration

Perpendicular Vibration

Direction of Energy

Direction of Energy

Transverse Waves• Transverse Examples: These waves can travel without a MEDIUM!

– Ocean Waves – All Electromagnetic Radiation (comes from sun)

• Radio Waves• Microwaves• Infrared (heat waves)• Visible Light• UV Rays• X-rays• Gamma Rays

– The only difference

between all EM wave

types is a change in

wavelength, frequency

and energy.

E-M Spectrum

E-M Spectrum

Longitudinal Waves

• Longitudinal Examples: These waves REQUIRE a MEDIUM to travel!

– Sound Waves• Cannot travel in space (no medium/matter)• Change in amplitude = volume• Change in wavelength = pitch

Standing Waves• A wave that remains in constant position.

This is also related to the concept of resonance.

Standing Waves

• A wave that remains in constant position. This is also related to the concept of resonance.

Fundamental Harmonic

2nd Harmonic

3rd Harmonic

4th Harmonic

Standing Waves

• Node: quiet part of a standing wave

• Anti-node: loud part of a standing wave

Node Anti-Node

Frequency Relationships

• (velocity of waves) = (wavelength) x (freq.)

– As wavelength gets smaller frequency goes up– As wavelength gets bigger frequency goes down

– As velocity gets higher, frequency goes up– As velocity gets lower, frequency goes down