Tides
Reading
Things to know
Forces that produce tides
- Tides are produced by what two “forces”?
- Why are there two tides a day?
- What is the shape of the “equilibrium tide”?
- Why is the lunar tide every 12.4 h (12 h and 25 mintues)?
Sketch…
Tidal variations
- What is meant by declination of Moon?
- Why do declinations result in uneven tides?
- what is meant by high-high tide and low-high tide?
- On what period does the moon’s declination change?
- What is the period of the moons elliptical orbit?
- what do perigree and apogee mean?
- can this alone explain spring-neap cycles? (How often is the
spring neap cycle?)
Solar/lunar combinations
- How often does the sun’s declination relative to the earth change?
- How often does it’s distance change? What are the names of the
closest and furthest distance, and how big are these changes
relative to the moon’s ellipse?
- Why do new and full moons correspond to spring tides?
- what is the name for this?
- What happens when the moon and sun are directly aligned?
- Why are there spring-neap cycles to the tides?
Dynamic theory
- How fast would a wave need to travel to follow the bulge of the
equilibrium tide? How deep would the ocean need to be to follow
such a wave? (the earth has a circumfrence of 40,000 km)
- What other effects prevent an equilibrium tide from being
observed.
- What is meant by an amphidromic system? What direction does water
flow arond them?
- what is a co-tidal line and a co-range line.
- Describe the practical method for predicting tides.
Types of tides
- Why do different basins have different tides?
Exercise
Exercise Tides
Last Modified: 09 July 2018 Licence: Creative Commons Attribution required, non-commercial uses (CC BY-NC 4.0)