Tides

THE TIDESHave you ever been to the beach?

If you go to the beach, you can see another pattern found in nature. During part of each day, the waves at the shoreline reach farther up on the beach than at other times. This time is called high tides. At other times, the waves do not seem to reach as far up the beach. This is known as low tides. This happens every day.

Low Tide High Tide

High and low tides are caused by the rotation of the Earth and the location of the moon.

The moon’s gravitational force pulls on the water on Earth’s surface.

The water moves out with a slight bulge on the side of the Earth that faces the moon. This causes high tide.

Texas has two high and low tides each day.

http://www.youtube.com/watch?v=l37ofe9haMU

Bulge

Bulge

What Causes Tides?High Tide

High Tide

High Tide

Low Tide

Low Tide

What Causes Tides continued…At the same time, the water also goes out farther on the opposite side of the Earth.

Earth is being pulled towards the moon and away from the water.

High tides occur on opposite sides of the Earth at the same time.

The high tide is even stronger when both the moon and the sun are on the same side of Earth.

Meanwhile, the rest of Earth has low tides.

Bulge

Bulge

Bulge = HIGH tide

http://www.brainpop.com/science/earthsystem/tides/ (Stop at 1:07)

High Tide

High Tide

High Tide

Low Tide

Low Tide

High Tides Vs. Low Tide

Spring Tide &

Neap Tide

Questions…Question: Look at the picture, if the water is at low tide, what will happen as time passes?

Looking at the two pictures, Picture A is an example of a ____ tide.Picture B is an example of a ____ tide.

A B

If you are at the beach during what is known as High tide what water is _____? (describe the water level) At its highest level

Tide Notes• The gravitational pull of the moon causes

the oceans on Earth to rise and fall.• High Tide. Water is at its highest level.– The moon’s gravitational force pulls the water

towards it.– Water moves out in a slight bulge on the side

of the Earth that faces the moon.– Water also goes out in the opposite side of the

Earth, since the moon pulls the Earth.– High tides occur on opposite sides of the Earth

at the same time.

• Low Tide. Water is at its lowest level during low tide.

Tide Clock