SPI 6.5

Predict the types of tides that occur when the Earth and the moon occupy various positions

https://www.brainpop.com/science/earthsystem/tides/

TidesTides are daily movements of ocean water

that change the level of the ocean’s surface.

TidesTides are influenced by the sun and the

moon, and they occur in a variety of cycles.

The Lure of the MoonThe gravity of the moon pulls on every particle of

the Earth.

The Lure of the MoonThe pull is much more

noticeable in liquids than in solids because liquids

move more easily.

The Lure of the Moon

Even the liquid in an open soft drink is slightly pulled by the moon’s gravity.

The Lure of the MoonGravitational forces from both the sun and

the moon continuously pull on the Earth.

The Lure of the MoonAlthough the moon is much smaller than the sun, the

moon’s gravity is the dominant force behind

Earth’s tides.

High and Low TidesHow high tides get and how often they occur

depend on the position of the moon as it revolves

around the Earth.

High and Low TidesThe moon’s pull is strongest on the part of the Earth

directly facing the moon.

High Tides vs. Low Tides

Because of inertia, water wants to fly off of earth, but is balanced by gravity. The water that is directly facing the moon gets

pulled (bulges) from the gravitational pull of the moon causing a high tide.

High Tides vs. Low Tides

The side directly opposite also experiences a hightide because as the moon is pulling the other side it throws off the earth’s center of gravity, causing more of a gravitational pull to be on the side with

the moon. Thus the effects of inertia on the opposite side become greater because there is less

of a gravitational pull. Here you also get a high tide.

High Tides vs. Low Tides

When high tides occur, water is drawn away from the area between the high tides, causing low tides to form.

High Tides vs. Low Tides

Copy this diagram into your notes in the space provided.

High Tides vs. Low Tides

Bay of Fundy at high tide Bay of Fundy at low tide

http://www.howitworksdaily.com/environment/bay-of-fundy-time-lapse/

http://www.youtube.com/watch?v=OP0cpXpw8yk

High Tide and Low Tide

Timing the TidesTides occur at differentspots on Earth because the Earth rotates more quickly than the moonrevolves around the Earth.

Tidal VariationsThe sun also affects tides.

The sun is much larger than the moon, but it is also much farther away.

Tidal VariationsAs a result, the sun’s influence on tides is less

powerful than the moon’s influence.The combined forces of the sun and the moon on the Earth result in tidal ranges that vary based on the positions of all three bodies.

Spring TidesWhen the sun, Earth,

and moon are in alignment with one another, spring tides

occur.

Spring TidesSpring tides are tides with maximum daily

tidal range that occur during the new and

full moons.

Neap TidesWhen the sun,

Earth, and moon form a 90° angle, neap tides occur.

Neap TidesNeap tides are tides

with minimum daily tidal range that occur during

the first and third quarters of the moon.

Neap TidesThe gravitational

forces on the Earth by the sun and the moon work against

each other.

Neap and Spring Tides

Tides and TopographyTides can be accurately predicted

once the tidal range has been measured at a certain point over

a period of time.

It’s a good thing that people on the beach knew when high tide

occurred.

Tides and TopographyThese photos show the Bay of Fundy, in New Brunswick, Canada.

The Bay of Fundy has the greatest tidal range on

Earth.