What do these pictures have in common?

2 Introduction to Waves

3 Waves are everywhere in nature Sound waves visible light waves radio waves microwaves water waves telephone chord waves stadium waves earthquake waves waves on a string slinky waves

4 What is a wave? A wave is a disturbance (source of energy) that travels through a medium from one location to another. A wave is the motion of a disturbance

Waves transfer energy not matter. The water waves below are carrying energy but are not moving. Waves can only exist as they have energy to carry.

Mechanical Waves Waves that require a medium to pass through. A medium is a material through which waves can pass Gases (air) Liquids (water) Solids (ropes) 6

What are two kinds of mechanical waves? Transverse Longitudinal (Compression) 7

Transverse Waves A disturbance that is perpendicular to the direction of the wave Ex. Moving a rope up and down. disturbance wave direction 8

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Example of a transverse wave:

Longitudinal (Compression) Wave The disturbance is parallel to the direction of the wave travel. Ex. Spring toy or SLINKY! Compression-the coils come together Rarefaction- the coils spread out 11

Example- Longitudinal Wave 12

13 Longitudinal vs. Transverse Waves The differences between the two can be seen

Properties of Waves Crest and Trough Amplitude Wavelength Frequency 14

Crest and Trough Crest-The highest part of a transverse wave Trough- The lowest part of a transverse wave 15

Amplitude-Transverse Wave 16

Amplitude- Longitudinal Wave Depends on how dense (bunched) the medium is at each compression. Coiled spring A has the greater amplitude. 17

Wavelength The distance between two corresponding parts of a wave. Crest to Crest Trough to Trough 18

Frequency The number of complete waves that pass a given point in a certain amount of time. Measured in hertz (Hz) 19 HIGH Frequency LOW Frequency

Review 1.Identify two types of mechanical waves. 1.What is amplitude? 1.If a wave has a high frequency, do the wavelengths become shorter or longer? 20