•Review of Sound Waves•Review of Sound Waves

• Waves move and carry energy• Waves travel in a medium • Waves are created when a source of energy causes

a medium to vibrate• Waves spread out as they move• Waves have different sizes and shapes• Waves pass through each other• Waves continue in the medium until they reach a

barrier• Waves do not disappear at barriers (waves diffract

around corners)

• Waves move and carry energy• Waves travel in a medium • Waves are created when a source of energy causes

a medium to vibrate• Waves spread out as they move• Waves have different sizes and shapes• Waves pass through each other• Waves continue in the medium until they reach a

barrier• Waves do not disappear at barriers (waves diffract

around corners)

•Sound•Sound• Sound is produced when objects vibrate

• It is a compression wave (or longitudinal wave)

• It needs something to travel through

• It travels through matter

• Sound is produced when objects vibrate

• It is a compression wave (or longitudinal wave)

• It needs something to travel through

• It travels through matter

•Sound Waves•Sound Waves

Molecules in the air vibrate about some average position creating the compressions and rarefactions.

Longitudinal Wave wave particles vibrate back and forth along the path that the wave travels.

Compressional Wave

Waves transfer energy without transferring

matter.

Waves transfer energy without transferring

matter.

Frequency= waves/time

• Frequency – How many wavelengths pass a point in a unit of time (the shorter the wavelength, the higher the frequency.)

Image: scanned from Multimedia Concepts – James Schuman

•Sound •Hz (Hertz) – 1 wavelength/sec.

•We hear it as pitch

•High frequency – high pitch

•Low frequency – low pitch