MECHANICAL WAVES

particles move parallel (same direction) to the direction the wave travels.

Ex: sound waves

LONGITUDINAL

particles move perpendicular (=at right angle, 90º) to the direction the wave travels.

Ex: ocean waves

TRANSVERSE

Model waves with a slinky:
Look how each loop can model the particles.

LONGITUDINAL

TRANSVERSE

Longitudinal waves

The direction of the vibration is parallel to the direction of the wave.

Parts of a longitudinal wave:

Compression: the parts of the wave where the particles are close together.

Parts of a longitudinal wave:

Rarefaction: the parts of the wave where the particles/loops are spread-out.

Parts of a longitudinal wave:

Wavelength: the distance between two identical points of the wave.
For example: between 2 compressions points or 2 rarefaction.

Sound Waves

• Mechanical Waves

• Sound waves, like other mechanical waves, transfer energy through a substance called a medium

• Particles in a medium become disturbed and pass on this disturbance to the next one, and so on. 

• NOTICE: particles move back and forth but return to their original position "ORIGIN"

Sound Waves

• Sound waves can travel through solids, liquids, or gases

• Notice the difference in speed between the different materials.

​Research in your notebook

Research: why sound travels faster in stainless steel than in air.