Types of Waves There are two ways we can group waves into different types based on the relationship of the wave to its medium mechanical electromagnetic surface based on direction of vibration in comparison to the direction of wave travel “back-and-forth” “up-and-down” or “side-to-side” “circular”

Waves and Their Media Mechanical waves require a medium to move through the medium can be any form of matter: solid, liquid, gas – even plasma the wave travels through the medium as the atoms of the medium bump into each other, passing along their energy based on the way mechanical waves move, we can see that they move faster through denser matter (solids) than they do through less dense matter (gases)

Waves and Their Media Electromagnetic waves do not require a medium to move through – they can move through a vacuum – but they can also move through matter the wave travels as alternating variations (vibrations) in the strength and direction of electrostatic and magnetic fields based on the way electromagnetic waves move, we can see that they move fastest in the absence of matter (a vacuum), and faster through less dense materials (gases) than they do through denser matter (solids)

Waves and Their Media Surface waves are a special type of mechanical wave that move along the boundary between two media that have different properties the wave travels primarily in the denser medium so its behavior is determined mostly by the properties of that medium; however, the atoms at the boundary of a material are not constrained in the same way as those within the “body” of the material, so their motion is different

Direction of Vibration In some mechanical waves, the particles/atoms move “back-and-forth” parallel to the direction of wave travel these waves are called longitudinal or compressional waves the “back-and-forth” particle motion alternately squeezes and stretches the medium this creates regions in the medium that have “higher than normal” density – called compressions “lower than normal density – called rarefactions

Direction of Vibration In some mechanical waves, the particles/atoms move “up-and-down” or “side-to-side” at right angles to the direction of wave travel these waves are called transverse or shear waves the “up-and-down” or “side-to-side” particle motion produces a waveform that has traditional crests and troughs ALL electromagnetic waves are transverse waves the electrostatic and magnetic fields both vibrate at right angles to the direction of wave travel

Direction of Vibration In some mechanical waves, the particles/atoms move in a combination of “back-and-forth” and “up-and-down” that results in a circular path this motion can only happen at the boundary between two media with different properties thus, a circular particle motion path occurs in surface waves surface waveforms have traditional crests and troughs

Wave Diagrams Longitudinal and transverse waves

Wave Diagrams Surface wave (water wave)

Wave Diagrams Electromagnetic waves