Topic 7: Tides

1. Topic 7: Tides Biggest ocean waves of all

2. Types of Tides • Tides are a combination of the solar and lunar tides (remember wave interference) • Solar tide – tide caused by the sun • Lunar tide – tide caused by the moon • High tide- crest at shore • Low tide- trough at shore • Tide range- distance between high & low tide • Ebb tide- tide going out • Flood tide- tide coming in

3. 5 Factors That Cause Tides • Gravitational pull of the moon • Gravitational pull of the sun • Centrifugal force of earth as it rotates • Position of the sun & moon • Angle of orbit of moon around earth

4. Gravitational Pull of the Moon moon • Moon produces a tide by exerting a gravitational force on the earth • Gravity – force of attraction between two bodies • Draws moon and earth toward each other • Centrifugal force keeps moon and earth from colliding Fg(moon) ocean earth Fc(earth)

5. Gravitational Pull of the Sun • Sun produces a tide by exerting a gravitational force on the earth moon Fg(moon) ocean sun earth Fg(sun) Fc(earth)

6. Lunar and Solar Tides • Gravitational pulls from the sun and moon each create an ocean tide • Lunar and solar tides combine to make a single tide wave Lunar tide Solar tide earth sun moon

7. Spring Tides • during a new and full moon • earth, sun & moon line up • produces highest of high and lowest of low tides

8. Neap Tides • during the 1st & 3rd quarter moons • earth, sun, and moon are at right angles • produces small high and low tides.

9. Tidal Time • Solar day is 24 hours • Lunar day is 24 hours 50 minutes. • Tides occur 50 minutes later each day. • Moon rises about 50 min later each night. • Lunar Month = One tidal month • 29.5 days • 2 spring tides • 2 neap tides