Question of the Day

What makes waves in the ocean SUPER

high???

*The Earth is covered in oceans….*70% of the Earth is water!!

What force do you think holds the water in the oceans to earth’s surface?

What force holds us to earth?

What force makes moons orbit planets?

What force makes planets orbit the sun?

* Gravity holds the (1)oceans to the earth, but the oceans still move

* The (2)movement of the ocean is called the tides

Sometimes, the tides will move the ocean farther away from the land

Sometimes, the tides will bring the ocean farther up onto the land

What causes tides?????

Just like objects on earth are pulled by the earth’s gravity, objects in outer space make gravity too

The moon and sun make gravity, and their (3)gravity pulls on earth’s oceans making the tides

The moon’s gravity pulls water on the side of Earth’s surface closest to it (4)more strongly than it pulls on the center of the Earth.

* This pull creates a bulge of water called a (5)tidal bulge on the side of the Earth that

is facing the moon.

In the places where there are tidal bulges, high tide is occurring along

the coastlines.

In the places between the bulges, low tide is occurring.

Earth’s rotation through the tidal bulges causes most coastlines to experience two

high tides and two low tides every 25 hours.

The Monthly Tide Cycle

* Even though the sun is about 150 million km from Earth, it is so massive that its

gravity ALSO affects the tide.* Changes in the positions of the Earth, the moon and the sun affect the height of the

tides during a month.

Spring Tide

• Two times a month, At a new moon and a full moon, the sun and moon are in

(6)one direct line• Their combined gravitational pull gives

the (7)GREATEST difference in water level between high and low tide• This is called Spring Tide

…spring like jump…not the season.

Neap Tide

• Two times a month, at the (8)waxing and waning quarters of the moon, the sun and moon are pulling at right angles to each other.

• This arrangement produces a neap tide- a tide with the (9)least difference between low and high tide.

• During this time, the sun’s gravity pulls away some of the tidal bulge…evening out the water level on the Earth’s surface.

Quick Check for SUPERSTAR Status

True or False: The ocean tides are not caused by the moon, but by how the wind is blowing.

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What causes tides in the ocean?A.The gravitational pull of the

moonB.The gravitational pull of JupiterC.Compression of the Earth’s crustD.The waves in the ocean

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Ocean tides are best described as:A. Nonpredictable and cyclicB. Nonpredictable and noncyclicC. Predictable and cyclicD. Predictable and noncyclic

Quick Check for SUPERSTAR Status Spring or Neap tide??

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During which phase of the moon will a spring tide occur?A. Waxing CrescentB. Waning CrescentC. Full Moon D. Waxing Gibbous

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Which type of tide would have the HIGHEST waves?

A.Spring tideB.Neap tideC.Fall Tide D.Ocean Tide

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Spring or Neap Tide??

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What is the force that causes tides to occur on Earth’s surface?

A. FrictionB. InertiaC. Gravity

EXIT TICKET

1. Describe the positions of the Sun, Moon and Earth during a Neap Tide.

2. Describe the positions of the Sun, Moon and Earth during a Spring

Tide.