Shake a rope and the wave runs along it while the rope itself flicks up and down, across the motion. Push a spring back and forth and the wave runs along it too, but now the coils bunch and stretch in the same line. Two ways for a wave to vibrate.
In a transverse wave the vibrations are at right angles to the direction the energy travels, as in light and water waves. In a longitudinal wave the vibrations are along the direction of travel, as in sound, which travels as compressions and rarefactions.
In a transverse wave the vibrations are at right angles to the direction of energy travel; in a longitudinal wave the vibrations are parallel to it.
In both, the particles vibrate about a fixed point and do not travel with the wave.
Switch between a transverse and a longitudinal wave and watch how the particles move relative to the wave.
Four quick checks. Each correct answer earns XP and lights this skill on your star map.
In a transverse wave the vibrations are...
In a longitudinal wave the vibrations are...
An example of a longitudinal wave is...
A longitudinal wave is made up of...
The single difference is the direction the particles vibrate compared with the direction the wave travels.
| Transverse | Longitudinal |
|---|---|
| Vibrations at right angles to travel | Vibrations along the direction of travel |
| Has crests and troughs | Has compressions and rarefactions |
| Light, water waves, all electromagnetic waves | Sound waves |
| Can travel through a vacuum (for EM waves) | Needs a medium to travel through |
In both types the particles only vibrate about a fixed point; they do not travel along with the wave. And sound is longitudinal, not transverse, a point examiners test often.
Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.
Which of these is a transverse wave?
In a sound wave travelling through air, the air particles...
A region where the particles of a longitudinal wave are pushed close together is called a...
Three wave skills down. Keep the chain going.