Pitkittäisaaltoina

Pitkittäisaaltoina, known in English as longitudinal waves, are a type of wave motion where the particles of the medium vibrate parallel to the direction of wave propagation. This means that the displacement of the medium's elements is in the same direction as the wave is traveling.

A common example of a longitudinal wave is sound. When a sound wave travels through air, it consists of compressions (regions of higher pressure and particle density) and rarefactions (regions of lower pressure and particle density). The air molecules are pushed and pulled in the direction the sound is moving. Another example can be observed in a Slinky toy. If one end of a stretched Slinky is pushed and pulled along its length, a wave of compressions and expansions will travel down the Slinky, with the individual coils moving back and forth parallel to the Slinky's axis.

In contrast to transverse waves, where particle displacement is perpendicular to the direction of wave travel (like waves on a string or light waves), longitudinal waves involve oscillations along the wave's path. This distinction is fundamental in understanding various wave phenomena in physics, from acoustics to seismology. The speed of a longitudinal wave depends on the properties of the medium, such as its elasticity and density.