Tides

Tides

Ch 1 L 5 p. 28-31

What Are Tides?

• The force of gravity pulls the moon and the Earth (including the water on Earth's surface) toward each other.

• Tides are caused mainly by differences in how much gravity from the moon and the sun pulls on different part of Earth.

Multiple Choice

_________ are caused mainly by differences in how much _________ from the moon and the sun pulls on different part of Earth.

• Tides; gravity

• Gravity; tides

• New moon; tides

• Gravity; new moon

What Are Tides?

• At any one time on Earth, there are two places with high tides and two places with low tides.

• As Earth rotates, one high tide occurs on the side of Earth that faces the moon.

• The second high tide occurs on the opposite side of Earth.

• Halfway between the high tides, water flows toward the high tides, causing low tides.

Multiple Choice

At any one time on Earth, there are ______ places with high tides and _____ places with low tides.

• two; two

• one; two

• two;one

• three;three

Multiple Choice

As Earth rotates, one high tide occurs on the side of Earth that faces the what?

• Moon

• Sun

• Star

What Are Tides?

• The moon's gravity pulls a little more strongly on the water on the side of Earth closest to the moon than on Earth as a whole.

• This difference causes a bulge of water on the side of Earth closest to the moon.

• The bulge causes high tide.

Multiple Choice

The moon's gravity pulls more strongly on side the closet to the what?

• The Moon

• The Sun

• The Stars

What Are Tides?

• The moon's gravity pulls more weakly on the water on the far side of Earth than on Earth as a whole.

• Since Earth is pulled more strongly, the water "left behind."

• Water flows toward the far side, causing high tide.

Multiple Choice

The moon's gravity pulls more weakly on the water on the what?

• Far side of Earth

• Closest side of Earth

Multiple Choice

Water flows toward the far side, causing what?

• High Tide

• Low Tide

What Are Tides?

• The sun is so massive that, even though it is about 150 million km from Earth, it's gravity also affects the tides.

• The sun pulls the water on Earth's surface toward it.

• Changes in the positions of Earth, the moon, and the sun affect the heights of the tides during a month.

Multiple Choice

The _______ pulls the water on Earth's surface toward it.

• Sun

• Moon

• Stars

Multiple Choice

Changes in the positions of Earth, the moon, and the sun affect the __________ of the tides during a month.

• Height

• Length

What Are Tides?

• The sun, the moon, and the Earth are nearly in a line during a new moon.

• The gravity of the sun and moon pull in the same direction.

• Their combined forces produce a tide with the greatest difference between consecutive low and high tides, called a spring tide.

Multiple Choice

Their combined forces of the sun, Earth, and moon, produce a tide with the greatest difference between consecutive low and high tides which is called what?

• Spring Tides

• Neap Tides

• High Tides

• Low Tides

What Are Tides?

• During the moon's first-quarter phase, the line between Earth and the sun is at right angles to the line between Earth and the moon.

• The sun's pull is at right angles to the moon's pull.

• This arrangement produces neap tide, a tide with the least difference between consecutive low and high tides.

• Neap tides occur twice a month.

Multiple Choice

What is a tide with the least difference between consecutive low and high tides?

• Neap Tide

• Spring Tide

• High Tide

• Low Tide

What Are Tides?

• At full moon, the moon and the sun are on opposite side of Earth.

• Since there are high tides on both sides of Earth, a spring tide is also produced.

• It doesn't matter in which order the sun, Earth, and the moon line up.

Multiple Choice

At full moon, the moon and the sun are on opposite side of Earth, therefore, what is produced?

• Spring Tide

• Neap Tide

• High Tide

• Low Tide

Review Questions

Time to see what you have learned!

Multiple Choice

_________ are caused mainly by differences in how much _________ from the moon and the sun pulls on different part of Earth.

• Tides; gravity

• Gravity; tides

• New moon; tides

• Gravity; new moon

Multiple Choice

At any one time on Earth, there are ______ places with high tides and _____ places with low tides.

• two; two

• one; two

• two;one

• three;three

Multiple Choice

As Earth rotates, one high tide occurs on the side of Earth that faces the what?

• Moon

• Sun

• Star

Multiple Choice

The moon's gravity pulls more strongly on side the closet to the what?

• The Moon

• The Sun

• The Stars

Multiple Choice

The moon's gravity pulls more weakly on the water on the what?

• Far side of Earth

• Closest side of Earth

Multiple Choice

Water flows toward the far side, causing what?

• High Tide

• Low Tide

Multiple Choice

The _______ pulls the water on Earth's surface toward it.

• Sun

• Moon

• Stars

Multiple Choice

Changes in the positions of Earth, the moon, and the sun affect the __________ of the tides during a month.

• Height

• Length

Multiple Choice

Their combined forces of the sun, Earth, and moon, produce a tide with the greatest difference between consecutive low and high tides which is called what?

• Spring Tides

• Neap Tides

• High Tides

• Low Tides

Multiple Choice

What is a tide with the least difference between consecutive low and high tides?

• Neap Tide

• Spring Tide

• High Tide

• Low Tide

Multiple Choice

At full moon, the moon and the sun are on opposite side of Earth, therefore, what is produced?

• Spring Tide

• Neap Tide

• High Tide

• Low Tide