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 / fPeriod = 1 / frequency

Types of Waves

LongitudinalParticles in the wave move parallel to the motion of the wave.

TransverseParticles in the wave move perpendicular to the motion of the wave.

Characteristics of Wave Types

LongitudinalCompression, rarefraction (stretching), wavelengths λ

TransverseCrests, 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

Standing wave

http://www.acs.psu.edu/drussell/Demos/StandingWaves/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?

Superposition Principle- the addition of waves

http://www.sciencejoywagon.com/physicszone/09waves/

http://www.feilding.net/sfuad/musi3012-01/html/lectures/004_sound_III.htm