http://images.google.com/imgres?imgurl=http://www.geo.umn.edu/orgs/umgs/Pictures/Hawaii%25202003/Day%252011/images/19%2520Crashing%2520waves.jpg&imgrefurl=http://www.geo.umn.edu/orgs/umgs/Pictures/Hawaii%25202003/Day%252011/pages/19%2520Crashing%2520waves.htm&h=800&w=1067&sz=79&hl=en&start=45&tbnid=G9X32W1VzxtNQM:&tbnh=112&tbnw=150&prev=/images%3Fq%3Dwaves%26start%3D40%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26sa%3DN

GPS

S8P4 You will explore the wave nature of sound and electromagnetic radiation.

a. Identify the characteristics of electromagnetic and mechanical waves.

f. Diagram the parts of the wave and explain how the parts are affected by changes in amplitude and pitch.

EQ

• Unit: How do waves of energy produce light and sound?

• Lesson: How does changing one part of a wave affect the total wave in terms of frequency and amplitude?

VocabularyWave Trough

Medium Longitudinal Wave

Mechanical Wave Compression

Vibration Rarefaction

Transverse Wave Surface Wave

Crest

What are Waves?

• A repeating disturbance or movement that transfers energy through matter or space.(place to place)

• Energy is the ability to do work.

Ocean waves carry energy along the surface of the water.

Where does the energy come from?

Wind moving over the water.

• During earthquakes, energy is transferred in powerful waves that travel through earth.

• Light is a type of wave that can travel through empty space to transfer energy from one place to another, such as from the sun to earth.

What Carries Waves?

Any substance through which waves can travel is a medium.

Examples: solids (rope), gases (air), liquids(water)

Waves that require a medium through which to travel are called Mechanical waves

Even though waves travel through a medium, they do not carry the medium with them.

Example:

Think of a cork floating on water. What happens as a wave moves past the cork?

The cork moves up and down, It does not move in the same direction as the wave. The wave moves through the water.

Do All Waves Need a Medium?

No.Electromagnetic waves do not need a

medium.Electromagnetic waves can travel

through solids, liquids, and gases, but they travel fastest through empty space.

Example: visible light

What Causes Waves?

Waves occur when a source of energy causes a medium to vibrate.

Vibration is a repeated back-and-forth or up-and-down motion.

Motion=wave

Waves are classified based on the direction in which the particles of the medium vibrate compared with the direction in which the waves travel. There are three classifications of waves based on this criterion.

Types of Waves

1. Transverse Waves (water)

2. Longitudinal Waves (sound)

(compressional waves)

3. Surface Waves

In a transverse wave, the medium vibrates in a direction at right angles to the direction the wave travels.

                                

Crests: the highest parts of the wave

Troughs: the lowest parts of the wave

                                

Longitudinal Waves

In a longitudinal wave, the medium vibrates parallel to the direction the wave travels.

                                 

Compressions: the parts where the coils are close together

Rarefactions: the parts where the coils are spread out

                                 

Slinky

Surface Waves

A combination of transverse and longitudinal waves.

Occurs between two mediums. Up-and-down motion combines with

back-and-forth motion. The combination produces circular

motion.

An example of a surface wave is a type of seismic wave formed as a result of an earthquake.

Slinky Lab

With a partner, make two different kinds of waves.

Create a T chart and list how they are similar and different

What are the characteristics of the waves?

Wave Simulation

http://phet.colorado.edu/new/simulations/sims.php?sim=Wave_Interference

http://www.classzone.com/books/ml_science_share/vis_sim/wslm05_pg18_graph/wslm05_pg18_graph.html