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• Remember Poster is due Friday at beginning of period. It is a major grade.

• Today we will do TAKS review over waves

• Pick up note sheet at front

• Book Check today-have it on your desk

What are the 2 types of energy?

Types of Energy can be classified as Potential Energy or Kinetic

Energy

WAVES

http://www.coe.uh.edu/texasipc/units/waves/wave.mov Intro to

Waves Clip

•WAVES

Wave: a repeating disturbance or movement that transfers energy through space or matter.

Ex light, sound, radio

Mediumany material that a wave transfers

energy through

ex. Water is the medium for ocean waves

What is the medium for sound when we talk?

MECHANICAL WAVES

• Type of wave that require a Medium to travel through

2 Types of Waves (Motion)

Compressional (Longitudinal)

Transverse

2a. Transverse Waves

• Motion of Molecules

Direction of Wave

Particles of the medium vibrate perpendicular (up & down) to the direction the wave is moving. ex. Water waves (looks like a rope)/Light

Transverse Waves

Animations of Transverse Waves

• http://www.kettering.edu/~drussell/Demos/waves-intro/waves-intro.html

2b. Compressional Waves

• particles vibrate is parallel to the direction of the wave. These waves require a medium (such as air or water) through which to travel.

• ex. Sound waves (looks like a spring)Direction of Movement

Direction of Wave

Longitudinal Waves

These two diagrams are waves that are a combination of transverse and longitudinal.

Longitudinal Waves

Transverse Waves

In water

In a solid

Measuring Transverse Waves

Interactive Website

3. Wave Properties- Definitions

a. Wavelength – the distance between one point on a wave and the nearest point just like it. The greek symbol is , called lambda.

b. Frequency – number of wavelengths () that pass a given point each second

c. Crest – the highest point of a transverse wave

Definitions continued….

d. Trough – the lowest point on a transverse wave

e. Amplitude – the measure of the energy of the wave (height for TW) ex. Large amplitude = more energy

f. Nodal Line – an imaginary line, it is the usual resting position of a wave

V = F V = F

V = Velocity of the wave (m/s) F = Frequency (hertz) (hz)

= wavelength (m)

is the Greek symbol called “lambda”.

• You are sitting on a float and the wave bounces you up 6 times every two seconds. This describes what?

• If the frequency of a wave is 10hz and there is 5 meters between each compression, the wave speed would equal?

What is the relationship between frequency and wavelength if speed is

constant?

At a constant speed, there is an inverse relationship between frequency and wavelength:

4. Transverse Wave Diagrams

Draw a transverse wave large enough to label 6 parts .

5. Parts of a compressional wave are:

A. A compression is the part where the particles of matter are pushed close together.

B. A rarefaction is the part where particles of matter are spread apart.

C. The wavelength is one complete compression and one complete rarefaction. SI unit is in meters.

Parts of a Longitudinal Wave

•one rarefaction and one compression together.

Wavelength:

Compressional Wave

Compression…………………………..Rarefaction

Animation of Tuning Fork

• http://faraday.physics.utoronto.ca/IYearLab/Intros/StandingWaves/Flash/tunefork.html

Animations of Seismic Waves

• Click here to see how a seismic wave is a combination of both transverse and longitudinal waves (NOTE: Longitudinal and Compression waves are the same thing)

• Another animation of both types of waves in seismic waves.

• Animations of land during earthquakes. (Half way down the page, the three animations next to each other)

What are two differences between sound waves and light waves?

SOUND WAVES LIGHT WAVES

What are two differences between sound waves and light waves?

SOUND WAVES LIGHT WAVES

REQUIRE A MEDIUM TO TRANSFER ENERGY

NO MEDIUM REQUIRED: CAN TRAVEL THROUGH A VACUUM

COMPRESSIONAL WAVE

TRANSVERSE WAVE

What is the difference between the following terms?

• Resonance

• Reflection

• Refraction

• Diffraction

• Polarization

What is the difference between the following terms?

• Resonance-Vibrating/Singing Wine Glass

• Reflection-Mirror/Echo

• Refraction-Bending due to change in medium (Pencil in Water)

• Diffraction-Bending around an opening

• Polarization-Aligning the waves in one direction (Sunglasses/Reduces Glare)

Resonance

• Tacoma Bridge Disaster

Reflection

Refraction

DIFFRACTION

The bendingof a wave as it passesan edge or opening

Ex. Ocean waves change direction and bend after striking an island Diffraction of a Monochromatic Light Source

Polarizing Filter Demonstration

Quiz

1. What is a medium?2. List 3 parts of a Transverse wave.3. List 2 parts of a Compressional wave.4. Give an example of a Transverse wave.5. Give an example of a Compressional

(Longitudinal) wave6. Why is there no sound in space?7. How is your image in the mirror similar to

hearing an echo?

Answers

1. A medium is made up of the molecules that transfer energy of wave motion.

2. Amplitude, Crest and Trough.

3. Compression and Rarefaction

4. Ocean Waves or Light

5. Sound Waves

6. No matter to transfer energy

7. Both are due to wave reflection