What is a series of compressions and rarefactions?

A series of compressions and rarefactions refers to the wave patterns found in longitudinal waves, such as sound waves. In these waves, compressions are regions where particles are closely packed together, while rarefactions are areas where particles are spread apart. This alternating pattern of high and low pressure travels through a medium, allowing energy to be transmitted without the bulk movement of matter. This phenomenon is essential for understanding how sound propagates through air and other materials.