1. Forces Equilibrium vs. Dynamic Tides

2. Forces that create tides
Earth-sun and Earth-moon systems
Example of swinging bucket
Centripetal forces
Gravitational forces
Resultant forces

3. Equilibrium tides Water covered earth (no continents)
No friction on earth
Drawings of earth-moon-sun system
Note position of bulges
Note alignment of earth-moon vs. earth-sun

4. Spring vs. Neap Tides

5. Dynamic tides Earth is not ideal Orbits are ellipses not circles
Basins have variable shapes
Earth is tipped on its axis as are other planetary bodies

7. Varieties of tides Diurnal tides: 1 high, 1 low per day
Semi-diurnal tides: 2 highs, 2 lows per day
Mixed tides: 2 highs, 2 lows per day, but of unequal heights (one example)

8. Consider highs and lows in each tidal day

10. Tides in inlets No swimming signs Tidal currents moving through inlet
ebb tidal current
flood tidal current
slack water

12. Tide height
Current speed

13. Tidal currents in rivers
Tidal bores:
strong river current meets strong flood tidal current and creates a wave!

15. Approaching tidal bore on river in Nova Scotia
Photo by MS Bollinger