Exercise 3 solution (model answer)

Resonance: the Bay of Fundy (with the Gulf of Maine) is about the right length and depth for a tide wave to travel in and back in roughly the time between tides, about 12 hours 25 minutes. Each incoming tide therefore arrives just as the reflected one returns, and the oscillation is reinforced, like pushing a swing at the right moment.

Funnel: the bay narrows and shallows toward its head, so the same volume of water is squeezed into a smaller space and must rise higher.

At a small island in the mid-Atlantic there is no coast to reflect the wave and no narrowing channel to concentrate it, so the tide there is under a metre.