A pier full of sail boats, perpendicular to the prevailing wave direction, and voila: Instant demonstration of an amplified wave!
![Screen shot 2015-09-26 at 5.06.57 PM](http://mirjamglessmer.com/wp-content/uploads/2015/09/Screen-shot-2015-09-26-at-5.06.57-PM-300x183.png)
Ratzeburg 2015
Look at how the masts show a transversal wave:
Maybe consider bringing this video as a backup when you are not sure whether your class will be able to do this visualization of transversal waves and calm back down again :-)