We'll explain the meaning of oppa, hyung, noona, or unnie. It's time to get clear on how you refer to the people you talk to in Korean. We'll explain the meaning of oppa, hyung, noona, or unnie.
Swell is the collection of waves moving away from a storm in the ocean. Although the waves will all be of different size and power and heading in slightly different directions we can tend to talk about averages of all these waves as one discreet swell.
A compression is the part of the wave (or Slinky) that is pressed together -- this is like the crest or peak of the wave. A rarefaction is the part of the wave (or Slinky) that is the most spread apart -- this is like the trough of the wave.