1. Tides

2. What is a tide TIDE: A periodic short-term change in the height of the ocean surface at a particular place. A tide is one huge _______________. When the high part, or of the wave reaches a particular location, _______ tide occurs. _____________ tide corresponds to the lowest part of the wave, or its ________________. wave crest high low trough

3. What Causes Tides? Tides are created by the imbalance between two forces 1. Force of the Moon and Sun on earth. 2. Force (center- seeking) required to keep bodies in nearly circular orbits. Gravitational Centrifugal

4. Gravitational forces on Earth due to the Moon Equation: ____________ Force is directed toward the moons center of mass. High tide occurs on side of earth closet to the moon. Force _____________ with increasing distance. G = m 1 m 2 __________________ r decreases

5. Centrifugal Force _______________ force associated with curved motion. Force that keeps water in bucket when you swing it around. Causes high tide on side of earth _____________ to the side of moon. Outward opposite

6. How many high/low tides a day? The earth spins on its axis ________ degrees every hour. As earth rotates, it goes into different bulges which cause high and low tides. There are roughly _______ high tides and ________ low tides a day. 15 2 2 TIDE CHART: http://www.tides4fishing.com/us/texas/galveston-pier-21

7. Spring Tide and Neap Tide Spring tide ______ degree alignment of earth, moon, and sun. Causes high tides to be very _____ and low tides to be very ___________. Neap Tide ______ degree alignment of earth, moon and sun. High tides are not very high and low tides are not very low. 180 high low 90 Animation: http://www.onr.navy.mil/focus/ocean/motion/tides1.htm