How fast things move differs greatly. Some things are so slow that their journey takes a long time; others move too fast for people to even see them.
For Grades: 6-8
Learning Goal 4
Vibrations in materials set up wavelike disturbances that spread away from the source. Sound and earthquake waves are examples. These and other waves move at different speeds in different materials.
Learning Goal 6
Light acts like a wave in many ways. And waves can explain how light behaves.
For Grades: 9-12
Learning Goal 5ab
The observed wavelength of a wave depends upon the relative motion of the source and the observer. If either is moving toward the other, the observed wavelength is shorter; if either is moving away, the wavelength is longer.