The marathon as an example of dispersion
Runners wear different colors based on how fast they run.
Dispersion is a
- Observe runners that move at different speeds along the course of a marathon.
- Observe and recognize that the runners in different colors moved at different speeds?
- Describe how runners of different speeds separated as the race went on?
- Discuss how the degree of sepration is related and thus a clue to the distance from the start.
What is the analogy?
- Discuss and recognize how this scenario is an analogy for the behavior of P and S waves.
- Because P and S waves move at a specific and constant speed, the lag time between these two waves is unique for each distance from an epicenter.
- For P and S-waves traveling at 6.5 and 3.5 km/s, at 100 km, the lag time is 14 seconds.
- Thus lag time can be used to determine distance from an epicenter.