Water On the Move- Tides ©Copyright 2014-all rights reserved www.cpalms.org

©Copyright 2014-all rights reserved www.cpalms.org Vocabulary Tidal Range- The difference in height between the high tide and the low tide Tidal Bulge- The “lump” of water created that occurs on two sides of the Earth, opposite from each other (where high tides are occurring) ©Copyright 2014-all rights reserved www.cpalms.org

©Copyright 2014-all rights reserved www.cpalms.org Vocabulary Spring Tide- When the tidal range is the largest during a 28 day period (usually occurs twice) Neap Tide- When the tidal range is the smallest during a 28 day period (usually occurs twice) ©Copyright 2014-all rights reserved www.cpalms.org

©Copyright 2014-all rights reserved www.cpalms.org Spring Tides New Moon If we were looking down at the Earth from above the North Pole during a spring tide this is what we could see (our eyes would need to be sensitive enough to notice the water levels form this distance… remember this is a model). Notice there is not much difference between high and low tide. Click: As a reminder this is what the moon phase would look like if we were looking up from Earth where we live. Would we be experiencing high or low tide if we could see the moon at this point in the Earth’s rotation? Full Moon ©Copyright 2014-all rights reserved www.cpalms.org

©Copyright 2014-all rights reserved www.cpalms.org Neap Tides 1st Quarter Moon If we were looking down at the Earth from above the North Pole during a neap tide this is what we could see (our eyes would need to be sensitive enough to notice the water levels form this distance… remember this is a model). Notice there is not much difference between high and low tide. Click: As a reminder this is what the moon phase would look like if we were looking up from Earth where we live. Would we be experiencing high or low tide if we could see the moon at this point in the Earth’s rotation? 3rd Quarter Moon ©Copyright 2014-all rights reserved www.cpalms.org

What would happen if the Sun did not affect the Earth’s tides? http://astro.unl.edu/classaction/animations/lunarcycles/tidesim.html Without the Sun’s effects the Earth would not have neap or spring tides. Ask for students response then click. Follow the link to demonstrate. Without the Sun’s effects the Earth would not have neap or spring tides. ©Copyright 2014-all rights reserved www.cpalms.org

©Copyright 2014-all rights reserved www.cpalms.org Gravity: Sun vs Moon Does the Sun or the Moon have the greatest effect on the Earth’s tides? http://astro.unl.edu/classaction/animations/lunarcycles/tidesim.html *** Ask question and get student responses. Click and have the students compare the difference the Sun makes on out tides compared to just the Moon’s. The tide does not even appear twice as high when the Sun is added meaning it’s gravitational pull on the water is weaker than the Moon’s .Follow the link to demonstrate. ©Copyright 2014-all rights reserved www.cpalms.org

©Copyright 2014-all rights reserved www.cpalms.org Even though the Sun is a much larger object (it has a larger gravitational force overall), it is much farther away (391x farther) from the Earth than the Moon, meaning the Sun’s effect on the Earth’s tides is much smaller than the Moon’s. Even though the Moon is less massive than the Sun, it still affects the water on Earth’s surface more than the Sun because the Moon is about 391X closer. The Sun is larger enough to keep the Earth in orbit, but not close enough to affect our oceans very much. 384,000 km ©Copyright 2014-all rights reserved www.cpalms.org

©Copyright 2014-all rights reserved www.cpalms.org As the Earth Turns Why are there two high tides and two low tides every day? http://astro.unl.edu/classaction/animations/lunarcycles/tidesim.html There are two tidal bulges on opposite sides of the Earth, aligned with the Moon. As the Earth turns faster than the Moon revolves, every area of Earth will move through the two tidal bulges and two areas of low water level. There are two tidal bulges on opposite sides of the Earth, aligned with the Moon. As the Earth turns faster than the Moon revolves, every area of Earth will move through the two tidal bulges and two areas of low water level. ©Copyright 2014-all rights reserved www.cpalms.org

©Copyright 2014-all rights reserved www.cpalms.org Why is the tidal range in this area of Canada different from that of our area? https://www.youtube.com/watch?v=EnDJ6_XpGfo Short answer: Geography!! Long answer: The continents and other geographical features can cause the water during the tides to build up and create extreme highs and lows, or they can be blocked by surface features and not have such extreme changes. This area of Canada works with the motion of tides making it very easy for the water to build up very high in the Bay. ©Copyright 2014-all rights reserved www.cpalms.org

©Copyright 2014-all rights reserved www.cpalms.org Note the Differences ©Copyright 2014-all rights reserved www.cpalms.org

©Copyright 2014-all rights reserved www.cpalms.org Reading a Tidal Graph At the crest the area would be on the same or opposite side of the Earth as the Moon. High tide. At the trough the area would be at a right angle to the Moon. Low tide. High Tide High Tide High Tide High Tide Where are the areas of high tide? [student suggestions], then click the mouse Low tides? [student suggestions], then click the mouse Where would this area be in relation to the position of the Moon where you see the crests? [Student suggestions] Where would this area be in relation to the position of the Moon where you see the troughs? [Student suggestions] Low Tide Low Tide Low Tide Low Tide ©Copyright 2014-all rights reserved www.cpalms.org