Topic: Waves

Aim: Describe the parts of a wave.

Do Now: Take out your HW dittohttp://www.youtube.com/watch?v=Z3O2Ju3ULvo

HW: Bottom of Kinetic and Potential Energy ditto/

Identify the type of wave described below.

1.Does not require a medium.

2.Compressional waves

3.Particles of the medium move PARALLEL to the direction of the wave.

4.Requires a medium.

5.Can travel through a vacuum.

6.Particles of the medium move at RIGHT ANGLES to the direction of the wave.

7.Sound waves

Parts of aTransverse wave

y- axis

x- axisNormal resting position

Crest

Trough

•Crest – high points

•Trough – lowest points

Crest

Trough

Amplitude

•Amplitude – height–Related to energy–High amp = a lot of energy

•Wavelength – distance bw 2 crests or 2 troughs

Wavelength

Wavelength

Parts of a Compression

al(longitudinal)wave

•compression = where particles are close together

•rarefaction = where particles are far apart

rarefaction

compression

•Wavelength = Distance bw 2 compressions or 2 rarefactions

wavelength

•High amplitude:–compression = particles are very close together

–rarefaction = particles are very far apart

Frequency

•# of waves passing a point in a given time

•1 wave = 1 crest + 1 trough

•As frequency increases, wavelength decreases

1 second

Hertz •Unit for frequency

•Hz•1 Hz = 1 wave per second

The human ear is capable of detecting sound waves with a wide range of frequencies, ranging between approximately 20 Hz to 20,000 Hz.

Period •Time it takes 1 wavelength to pass a point

•Units = seconds•As frequency increases, period decreases

Low period

High period

Let’s summarize…

1.Describe the parts of a transverse wave.

2.Describe the parts of a longitudinal wave.

3.Describe the frequency of a wave.

4.Describe the relationship between frequency and wavelength.

5.Identify the units for frequency.

6.Describe the period of a wave.

7.Describe the relationship between frequency and period.

http://www.brainpop.com/science/energy/waves/

A

Identify each part of a wave labeled in the diagram above.

B

C

D

Which change in wave properties increases wave amplitude?

1.Increased wavelength

2.Increased height

3.Decreased frequency

4.Shortened wavelength

Which is the lowest part of a transverse wave?

1.Amplitude

2.Crest

3.Period

4.Trough

The height of a transverse wave is known as its

1.amplitude

2.crest

3.period

4.trough

The part of a longitudinal waves where particles are farther apart is known as the

1.crest

2.compression

3.trough

4.rarefaction

Which of the following changes in wave properties is a result of an increase in wavelength?

1.Higher crests

2.Reduced height

3.Lower frequency

4.Faster movement

The number of waves passing a point at a given time is known as

1. wavelength

2. frequency

3. period

4. amplitide

The time it takes one wavelength to pass a certain point is known as

1. wavelength

2. frequency

3. period

4. amplitude

Which of the following best describes the relationship between frequency and wavelength?

1.If the frequency remains constant, wavelength increases.

2.The wavelength decreases and frequency decreases.

3.The frequency increases as wavelength decreases.

4.If the wavelength remains constant, frequency increases.

1. Which wave has the greatest amplitude?

2. Which wave has the greater wavelength?

3. Which wave has the greater frequency?