Daily TidesDaily Tides

Tides happen regularly no matter what the wind is Tides happen regularly no matter what the wind is doingdoing

Tides occur in all bodies of water but are most Tides occur in all bodies of water but are most noticeable in oceans. noticeable in oceans.

High Tide- as the tide comes in toward the beach High Tide- as the tide comes in toward the beach and reaches its highest pointand reaches its highest point

Low Tide-as the tide flows back toward the sea and Low Tide-as the tide flows back toward the sea and reaches its lowest pointreaches its lowest point

Daily Tides Daily Tides The moon gravity pulls on the water on the Earth’s The moon gravity pulls on the water on the Earth’s

Surface. The moon pulls on the water on the side Surface. The moon pulls on the water on the side closest to it more than it pulls on the center of closest to it more than it pulls on the center of the earth. This pull creates a Tidal bulge, a bulge the earth. This pull creates a Tidal bulge, a bulge of water on the side of the earth that is facing the of water on the side of the earth that is facing the moon . On the other side of the earth is a bulge moon . On the other side of the earth is a bulge of water that is pulled less strongly than the of water that is pulled less strongly than the center of the earth. Where the tidal bulges are is center of the earth. Where the tidal bulges are is where high tides occur. As the earth rotates where high tides occur. As the earth rotates different part of the earth's surface pass by these different part of the earth's surface pass by these areas and experience the water level changes.areas and experience the water level changes.

The Daily Tidal CycleThe Daily Tidal Cycle

1.1. All areas of the world oceans pass under All areas of the world oceans pass under the moon every 24 hours and 50 minutes. the moon every 24 hours and 50 minutes. The cycle takes more than one day, each The cycle takes more than one day, each day the tides occur at different timesday the tides occur at different times

2.2. Every coastal area has at least one high Every coastal area has at least one high tide and one low tide every daytide and one low tide every day

3.3. Factors which influence the daily Tidal Factors which influence the daily Tidal patterns are:patterns are:

1.1. The earth’s surfaceThe earth’s surface2.2. Shape of the ocean floor/coastlineShape of the ocean floor/coastline3.3. Coriolis effectCoriolis effect

Tidal PatternsTidal Patternsdetermined by how many high and low tides determined by how many high and low tides in a 24 hour period.in a 24 hour period.

1. 1. Diurnal Tides-Include a single high Diurnal Tides-Include a single high tide tide and a single low tide each day.and a single low tide each day.

Example-Southeastern US along Gulf of Example-Southeastern US along Gulf of MexicoMexico

2. 2. Semidiurnal Tides-Include two high Semidiurnal Tides-Include two high tides and two low tides each day.tides and two low tides each day.

Example-Atlantic Coast of USExample-Atlantic Coast of US

3. 3. Mixed Tides-Inequality of tide levels Mixed Tides-Inequality of tide levels that has multiple high and low that has multiple high and low

tides.tides.

Example- Pacific Coast of USExample- Pacific Coast of US

Tide patterns around the Tide patterns around the worldworld

Monthly Tide CycleMonthly Tide Cycle1.1. The sun’s gravity also effects the The sun’s gravity also effects the

Earth, even though it is far away it Earth, even though it is far away it is very large. The sun’s gravity is very large. The sun’s gravity pulls the earth’s water toward it. pulls the earth’s water toward it. Sometimes the moon and sun pull Sometimes the moon and sun pull the earth’s water in the same the earth’s water in the same direction other times they pull in direction other times they pull in different directions.different directions.

Spring tidesSpring tides

1.1. Twice a month at the new moon Twice a month at the new moon and the full moon, the sun and and the full moon, the sun and moon are lined up. moon are lined up.

2.2. These combined gravitational pulls These combined gravitational pulls cause the greatest tidal ranges.cause the greatest tidal ranges.

3.3. Spring comes from the word to Spring comes from the word to jump and does not refer to the jump and does not refer to the season!!!season!!!

Neap TidesNeap Tides

1.1. At the first quarter (waxing) and third At the first quarter (waxing) and third quarter (waning) moons, the sun and quarter (waning) moons, the sun and moon pull at right angles to each other. moon pull at right angles to each other.

2.2. Least tidal range due to the sun’s Least tidal range due to the sun’s gravity pulling some of the water away gravity pulling some of the water away from the tidal bulge facing the moon from the tidal bulge facing the moon thus evening out the difference thus evening out the difference between low and high tide.between low and high tide.

http://upload.wikimedia.org/wikipedia/commons/0/03/Spingtide.jpg

http://upload.wikimedia.org/wikipedia/commons/c/c2/Neaptide.jpg

Tidal RangeTidal Range

Tidal Range is the difference in height between high Tidal Range is the difference in height between high and low tides.and low tides.

1.1. Spring Tides-Are the highest tidal rangeSpring Tides-Are the highest tidal range

2.2. Neap Tides-Lowest tidal rangeNeap Tides-Lowest tidal range

http://home.hiwaay.net/~krcool/Astro/moon/moontides/

Monthly Tide TablesMonthly Tide Tables

Scientists can fairly accurately predict Scientists can fairly accurately predict tides at various locations. These are tides at various locations. These are published as tide tables. Who is it published as tide tables. Who is it important to, in order to know the important to, in order to know the times and heights of the tides?times and heights of the tides?

Tidal PowerTidal Power

The movements of water between high and The movements of water between high and low tide are a source of potential energy. low tide are a source of potential energy. The first large scale tidal power plant was The first large scale tidal power plant was built in 1967 on the Rance River in France. built in 1967 on the Rance River in France. As the tide comes in gates open up into a As the tide comes in gates open up into a basin. As the tide retreats the gates close, basin. As the tide retreats the gates close, gravity pulls the water back through tunnels gravity pulls the water back through tunnels back to sea. The energy that travels back to sea. The energy that travels through the tunnels generates electricity.through the tunnels generates electricity.

Table discussionTable discussion

The first part of putting turbines into The first part of putting turbines into Admiralty Islet in Seattle to use tides to Admiralty Islet in Seattle to use tides to convert tidal energy into energy for convert tidal energy into energy for 710 homes is occurring. What impacts 710 homes is occurring. What impacts do you think this may have on the do you think this may have on the Ecology of the area. Do you think that Ecology of the area. Do you think that the impacts are worth it? (in other the impacts are worth it? (in other words, which is the greater good) words, which is the greater good) Explain why?Explain why?

Shoreline Processes and Shoreline Processes and FeaturesFeatures

Beach: A shoreline built of sediments that Beach: A shoreline built of sediments that are locally available. The sediment is not are locally available. The sediment is not stagnant, the waves are constantly stagnant, the waves are constantly moving it. The cycle of the beach is moving it. The cycle of the beach is determined by the amount of sand and the determined by the amount of sand and the surf condition. surf condition.

http://videos.howstuffworks.com/hsw/15732-erosion-on-the-move-beach-erosion-video.htm

BermBermDuring the winter During the winter

months, when months, when weather is often weather is often bad, there are bad, there are powerful waves powerful waves with short periods with short periods between crests. between crests. Beach sand is Beach sand is moved away and moved away and the berm moves the berm moves further inland. further inland.

In summer sand is In summer sand is brought in and the brought in and the beach builds up beach builds up creating a berm creating a berm that is closer to that is closer to the shorelinethe shoreline

Forces acting on the Forces acting on the shorelineshorelineHow are each of the following impacting How are each of the following impacting

beaches?beaches?1.1. Wave impactWave impact2.2. Abrasion (grinding of rock fragments)Abrasion (grinding of rock fragments)3.3. Wave refraction (bending of waves)Wave refraction (bending of waves)

- because of refraction wave - because of refraction wave energy is concentrated against the energy is concentrated against the sides and ends of headlands and is sides and ends of headlands and is weakened in baysweakened in bays

Long shore TransportLong shore Transport

Sands can be carried parallel to shore Sands can be carried parallel to shore by long shore current. If a by long shore current. If a breakwater or jetty is inserted it breakwater or jetty is inserted it breaks up this motion and a beach breaks up this motion and a beach will form on the up-current side of will form on the up-current side of the obstruction. the obstruction.

Provincetown, Mass. Was formed by a longshore current

Erosional and Depositional Erosional and Depositional FeaturesFeaturesUse the Earth Science book pg.463-465 to draw (or make a Use the Earth Science book pg.463-465 to draw (or make a

paper model) an example of each of the following Erosional paper model) an example of each of the following Erosional and Depositional Features-make sure to label each type and Depositional Features-make sure to label each type and whether it is erosional or depositional. The is an and whether it is erosional or depositional. The is an example over the paper towel dispenser.example over the paper towel dispenser.

Wave cut Cliffs and PlatformsWave cut Cliffs and PlatformsSea ArchesSea ArchesSea StacksSea StacksSpitsSpitsBarsBarsTombolosTombolosBarrier IslandsBarrier Islands

Can you name these?Can you name these?