Simple Nature - Light and Matter

c / As the wave pattern passes the rubber duck,put. The water isn’t moving with the wave.the duck staysd / As the wave pulse goesby, the ribbon tied to the springis not carried along. The motionof the wave pattern is to theright, but the medium (spring) ismoving from side to side, not tothe right. (PSSC Physics)2. The medium is not transported with the wave.The sequence of three photos in figure c shows a series of waterwaves before it has reached a rubber duck (left), having just passedthe duck (middle) and having progressed about a meter beyond theduck (right). The duck bobs around its initial position, but is notcarried along with the wave. This shows that the water itself doesnot flow outward with the wave. If it did, we could empty one end ofa swimming pool simply by kicking up waves! We must distinguishbetween the motion of the medium (water in this case) and themotion of the wave pattern through the medium. The mediumvibrates; the wave progresses through space.self-check AIn figure d, you can detect the side-to-side motion of the spring becausethe spring appears blurry. At a certain instant, represented by a singlephoto, how would you describe the motion of the different parts of thespring? Other than the flat parts, do any parts of the spring have zerovelocity? ⊲ Answer, p. 924A worm example 1The worm in the figure is moving to the right. The wave pattern,a pulse consisting of a compressed area of its body, moves tothe left. In other words, the motion of the wave pattern is in theopposite direction compared to the motion of the medium.Surfing example 2342 Chapter 6 Waves