# WAVES. What do these things have in common?

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WAVES

What do these things have in common?

Think about what characteristics make these things similar and write them down.

Characteristics of a Wave Amplitude, A - the maximum displacement of wave

Characteristics of a Wave Period, T -the time it takes to complete one cycle in seconds

Characteristics of a Wave Frequency, f -number of cycles/vibrations per unit of time. Unit is Hz - Hertz High f Low f

Characteristic of a Wave Wavelength, λ, length of a wave measured in meters.

Relationship between period and frequency- it’s complicated… f = 1 / T frequency = 1 / Period or T = 1 / f Period = 1 / frequency

Types of Waves Longitudinal Particles in the wave move parallel to the motion of the wave. Transverse Particles in the wave move perpendicular to the motion of the wave.

Characteristics of Wave Types Longitudinal Compression, rarefraction (stretching), wavelengths λ Transverse Crests, troughs, wavelengths λ

Draw Wave Label Crests Troughs Wavelengths Period Amplitude Transverse

Draw Wave Label Compression Rarefractions Wavelengths Period Amplitude Longitudinal

Speed of Wave Speed = distance / time Speed = amount of distance a wave travels / time it takes the wave to cover that distance

Example Mac and Tosh are resting on top of the water near the end of the pool when Mac creates a surface wave. The wave travels the length of the pool and back in 25 seconds. The pool is 25 meters long. Determine the speed of the wave.

Example The period of a wave is 0.0300 seconds. It travels at a velocity of 10.0 m/s. Determine the frequency and the wavelength of the wave.

STANDING WAVES A standing wave is a traverse wave that does not travel. For this to happen, both ends of the waves need to be attached to something.

Standing wave

http://www.acs.psu.edu/drussell/Demos/Standi ngWaves/StandingWaves.html

Nodes and antinodes Nodes- places of no displacement on a wave Antinodes – midway between nodes and a place where displacement is at a maximum

How many nodes/antinodes? 5 nodes 4 antinodes

How many nodes/antinodes? Nodes? Antinodes?

Interference Interference is when waves add or subtract and interact with each other

Types of Interference CONSTRUCTIVE Adding up of waves DESTRUCTIVE Subtracting waves

What kind of interference?