Earth Science Rocks!Warm Up January28

What causes waves? Wind

Waves also occur in rivers, lakes, and puddles.

•MYP Unit Question: How do we use water?

•Area of Interaction: Health and Social Education

•Learner Profile: Thinker and Balanced

•Standard: Recognize the significant

role of water in the Earth’s processes.•Learning Standard: I’m learning about currents

because they move water through the oceans.

Earth Science Rocks!• Opening: Survivor IMMUNITY

Challenge• Work Session: Notes over Tides• Closing: Tide Simulation

TIDES !!!

If it’s written in yellow, write it down.

So what causes tides?The word "tides" is a basic term used to define the alternating rise and fall in sea level with respect to the land.

Tides are produced by the gravitational pull of the moon and the sun.

•Bay of Fundy •known for having the

highest tidal range in the

world.Atlantic OceanGulf of Maine,

U.S.

Tidal Bulges...

The water “bulges” toward the moon because of the moon’s gravitational pull.

HIGH TIDEHIGH TIDE

LOW TIDE

LOW TIDE

• Draw this image on your foldable under TIDES.

The moon at work...• The water is pulled

toward the moon at point A.

• The water is pulled AWAY from the sides perpendicular to point A.

How often do we have high tides and low tides?

• Let’s figure it out…

Did you figure it out?In general, there are 2 high

tides and two low tides each day.

Because the Earth rotates more quickly than the moon revolves around the Earth, tides do not occur at the same time each day.

So why are tides not exactly 12 hours apart?

• Since the moon moves around the Earth, it is not always in the same place at the same time each day. So, each day, the times for high and low tides change by 50 minutes.

O.K. Let’s make it simple…

• We get one high tide every 12 hours and 24 minutes .

Spring & Neap TidesThe Moon doesn’t work alone. Remember the Sun’s gravity also affects tides.• SPRING TIDES The Sun & Moon may work together to produce higher than normal tides.

• NEAP TIDES The Sun & Moon may work against each other to produce lower than normal tides.

NEAP TIDE

SPRING TIDES

Lower than

normal tides

Higher than

normal tides

• Notice Spring & Neap tides only occur at certain phases of the moon.

How often do Spring & Neap tides occur?• Uh…I need to see

that picture again before I can answer that!

• I know the answer. Let’s move on.

• Why are ocean tides so different everywhere?"Because they depend on many factors including the topography of your local coastline, and exactly where the Sun and Moon are located.

• Closing: Tide Simulation• Get in a “circle” and hold hands. As the “moon” walks around behind you, lean toward it.