Unit 4 Chapter 2 Section 3 Tides

When the sun and moon are at right angles to each other, how are tides affected?

(Moderate tides are produced. The high tides are lower and the low tides are higher.)

Why do ocean bulges occur on Earth?

(On the half of the earth closer to the moon, the moon's gravitational force pulls strongly on the ocean water. As the gravitational force draws the water closer to the moon, inertia pulls to keep the water in place. The gravitational force is stronger than the inertia on this side of the earth, so the water ends up bulging on the side near the moon. On the opposite half of the earth, inertia is more powerful than the moon's gravitational pull because the moon is farther away. Inertia is what causes the movement of the water to create a bulge on this half of the earth.)

Compare spring and neap tides.

(Spring tides occur when the sun, moon, and Earth are aligned. Spring tides have a wide daily tidal range, so the ocean rises and falls more than usual, and they occur twice a month, during the new moon and full moon. Neap tides happen during the moon's first and third quarters, when the sun and the moon are at right angles to each other. Neap tides are moderate. During neap tides, high tides are lower and low tides are higher, resulting in the lowest daily tidal range.)

Why do tides not appear the same in different regions of the world?

(The earth is not smooth. Ocean waters are not free to flow over the Earth's entire surface in a continuous pattern. Large continents create natural barriers that ocean tides must travel around. Ocean water is also trapped by ocean basins and blocked by mid-ocean ridges and other underwater landscape features. The earth's rotation and the resulting Coriolis effect also influence the oceans movement. These variations combine to produce different patterns of tides in different regions.)

How do the gravitational forces of the moon and the sun produce tides?

(The gravitational forces acting along the curves in space-time allow the moon to pull on every molecule on Earth. This force is most noticeable with liquids like water. "the moon exerts a force on all bodies of water, but it is only visible in very large bodies of water. Tides are produced as the earth spins and different regions of the world are facing the moon at various times throughout the day. The gravitational attraction is stronger on whatever area of the earth is facing the moon. The sun's gravitational pull also affects tides. It is not as strong as the moon's pull because the sun is farther away from Earth. Sometimes the gravitational forces of the moon and the sun combine to produce higher tides called spring tides.)

neap tide

a tide that occurs when the sun and moon are at right angles to each other

spring tide

a tide that occurs when the sun, moon, and Earth are aligned

tidal range

the difference in water height between high and low tide