10.4. Waves and Wave Properties http://www.ck12.org
FIGURE 10.14
In a longitudinal wave the medium (the
spring in this case) vibrates parallel to the
direction of travel of the wave (v).http://www.youtube.com/watch?v=ubRlaCCQfDk&feature=related
Transverse Waves
Atransverse waveconsists of vibrations that are perpendicular to the wave direction. Examples of transverse
waves include cracking a whip, earthquake S-waves, and light (as well as other electromagnetic radiation). How
does a transverse wave transport (or propagate) energy?
Imagine a long rope held at one end by a person and the other end anchored as shown inFigure10.15. If the person
moves the rope in an up-and-down motion, parts of the rope will move up and down as the energy is propagated
along the rope. The motion of each portion of the rope will be perpendicular to the direction of propagation of energy
(that is, the direction of the wave).
FIGURE 10.15
In a transverse wave the medium (the
rope in this case) vibrates perpendicular
to the direction of wave travel (v).http://demonstrations.wolfram.com/LongitudinalAndTransverseWaves/
Just as in the case of longitudinal waves, there is no net transfer of mass in transverse waves. In the example above,
each piece of the rope will vibrate up and down about its equilibrium position as the energy propagates through the
rope. Similar to the longitudinal example, the speed with which the energy propagates through the rope depends
upon the properties of the rope, for instance, its linear density and tension.
Waves Undergo Reflection
It is easy to see that light waves canreflect. That is, they can bounce off the boundaries between the two media, as
shown inFigure10.16. When we look into a mirror, the light travels from our face to the mirror and back to our