Making waves
Question: Why does a boat’s wake last so long in a fluid as “runny” as water?
If you go to the Lake District and climb down Cat’s Bells, you can look down on
Derwent Water and watch the ferries. Each wake is many times the length of the
boat producing it and lasts for a long time.
Answer: The fact that water is a “runny” (not viscous) liquid does not
prevent it from forming a moving wave. Because low viscosity means little
friction and consequently little damping, it is in fact neccessary for a wave to
be able…
