Kayde Ford Sean Esposito

Waves:Waves- a vibratory disturbance that travels

through a material or space [ex: sound, water waves, light, heat waves

A wave may be longitudinal, transverse, or a combination of both, depending on the direction in which the medium vibrates in relation to the movement of the wave’s energy.

Waves & EnergyWaves transfer energy without the transfer of

massWaves can be produced in two ways:

A. Vibration of Particles Requires a medium for transfer Mechanical waves

SoundsWater Drops

EX: Sound, Water waves, Spring Waves

Waves & Energy Cont..B. Small changes in the strength of an

electromagnetic field Requires no medium for transfer EX: light, microwaves, x-rays

Electromagnetic Wave 1 Electromagnetic Wave 2

In which direction will segment X move as the wave passes through it?

(1)down, only (2)up, only (3) down, then up, then down (4) up, then down, then up

ANSWER:

(4) Up, than down, than up

Pulses & Periodic Waves1. Pulse – single vibratory disturbance

that moves from point to point

Medium only moves up and down

2. Periodic Wave – series of evenly timed disturbances in a medium

Periodic Waves

PULSE PERIODIC WAVE

D. Vibrations and WavesTransverse Waves- vibrational disturbance which

is perpendicular to the direction in which the wave travels

Unlike longitudinal waves, transverse waves can be oriented in many different planes.

Ex) water waves, seismic waves, electromagnetic waves (light, microwaves, radio waves)

Transverse waves

C. Longitudinal Waves- medium moves parallel to the direction in which the wave travels

ex) sound - Guitar String

Characteristics of Periodic Waves:Speed-Wavelength-Frequency-Period-(T) –Amplitude-Crest-

Frequency (f) = # of Vibrationsseconds

= # of Cyclesseconds

= Hertz (Hz)

Cycle= (Single vibration)

Ex) How many cycles between the dots?

ANSWER:3 Cycles

Ex) 10 cycles pass a fixed point in a wave train in 5 seconds.

What is the frequency of the wave?

F= # of cycles

f = 10 cycles =  2 cycles   F= 2 Hertz

5 seconds

1 second

seconds

Sound, frequency is pitch.Light, frequency is color.

T =f1

Period : time for an entire wave cycle to pass a given point in a medium

-determined by source of vibration not medium

distance between two consecutive points in phase

determined by mediumsymbol  λ = lambda

Is the maximum change in position of a particle from its rest position during a single vibration

Amplitude of a wave shows the amount of energy in the wave

Amplitude is a measure of loudness for sound and brightness for color

Amplitude

Phase

"In Phase" (0°) – points on a single periodic wave that have the same displacement (from equilibrium  position) and moving in the same direction

Whole number of wavelengths apartA & E, A & I, A & MB & F, B & J, B & N

Phase

"Out of Phase"– (1800) - same displacement from equilibrium position but going in a different direction

½, 1½, 2½ etc wavelengths apartA & C, B & D, F & H

Which 2 points are in phase?

C and F

B and D E and G

Name 2 points that are 180° out of phase?

QUIZquizQUIZ

quizquizquiz

quiz1. __________________ a vibratory disturbance

that travels through a material or space 2. __________________single vibratory

disturbance that moves from point to point3. _________________series of evenly timed

disturbances in a medium4. _____________= #vibrations/sec5. _____________– distance between two

consecutive points in phase6. ___= 1/f

Waves are everywhere!

Whether we recognize it or not, we encounter waves on a

daily basis. Sound waves, visible light waves, radio

waves, microwaves, water waves, sine waves, cosine

waves, stadium waves, earthquake waves, waves on

a string, and slinky waves and are just a few of the examples of our daily encounters with waves. In addition to waves,

there are a variety of phenomenon in our physical world which resemble waves

so closely that we can describe such phenomenon as

being wavelike.

Transverse and Longitudinal

Categories of Waves:Transverse: Longitudinal:

Amplitude:

• The maximum absolute value

of a periodically

varying quantity.

• Amplitude has the unit of the quantity that is changing (ex. displacement,

pressure, field strength,

etc.)

Period: the time between successive cycles

of a repeatin

g sequenc

e of events. The SI unit of

period is seconds.

Formula: T= t/n (time per number of cycles)

the number of cycles of a repeating sequence of events in a unit interval of time.

ƒ = n/t (number of cycles per time).

Frequency and period are reciprocals (or inverses) of one another.

The SI unit of frequency is the hertz.

Two points on a wave with the same phase have the same…

Phase is an angular quantity:

quantity of disturbance (ex. displacement) and

rate of change of disturbance (ex. velocity).

Adjacent points in phase are separated by one complete cycle.

Adjacent points out of phase are separated by half a cycle.

Wavelengths

Speed!

•the rate of change of distance with time

•the product of wavelength and frequency for periodic waves. •frequency and wavelength are

inversely proportional. -Lower frequency waves have

longer wavelengths. -Higher frequency waves have

shorter wavelengths. •the speed of a wave is

sometimes known as its wave speed

•the SI unit of speed is the meter per second [m/s].

1.What are the two categories of waves?2.Do lower frequency waves have shorter or longer wavelengths?3.What is the SI unit of frequency?4.What is the formula for period?5.What is displacement, pressure, and field strength and example of?

http://paws.kettering.edu/~drussell/Demos/waves/wavemotion.html

http://www.indiana.edu/~emusic/acoustics/amplitude.htm

http://www.qrg.northwestern.edu/projects/vss/docs/Communications/2-how-are-frequency-and-wavelength-

related.html