Science: Tides and the Lunar Cycle

Even though the same amount of the moon is always lit by the sun, we see the moon in phases because of...

... our view from earth

Neap tides occur during...

1st and 3rd quarter moons

How many tides are there every day?

2 high and low

To understand why the ocean tides rise and fall each day, you first have to look at the relative relationship between the Sun, Earth, and the Moon. The relative position and gravity of each of these celestial bodies is important in the formation of the ocean tides.

As the Moon revolves around the rotating Earth, Earth is revolving around the Sun. All three bodies are in constant motion, and the relative position of each is constantly changing in a cyclical and predictable pattern.

Newton's Law of the Universal Gravitation states that all objects that have mass exert a gravitational attraction between all other objects. This is true for all objects in the universe. The Sun, Earth, and Moon are no exception. The gravitational force between the three bodies is what causes the ocean tides.

As the moon and Sun exert a gravitational pull on the waters of Earth, Earth rotates, which changes the location of the pull. By continually changing the location of the Earth, Earth's rotation results in most costal areas experiencing two high tides and two low tides each day.

The gravitational pull from the Sun, while not as influential as that of the Moon, does have an effect on the ocean tides in the formation of two special tides, spring tides and neap tides. When the Sun, Earth, and Moon are aligned in a straight line, such as occurs during a full moon and a new moon, the gravitational pull from the Sun works with the pull from the Moon to create tides with a great tidal range.

During spring tides, the high tides are at the highest and the low tides are at the lowest. Neap tides occur when the Sun, Earth, and Moon are aligne to form a right triangle, such as occurs during the first quarter moon and the last quarter moon. In these positions, the gravitational pull from the Sun works against the pull from the Moon to create tides with a very small tidal range. Neap tides can have a tidal range of only a few centimeters with high tide and low tide levels close to the same.

What are the two main factors that create the tides on Earth?

Gravitational forces and rotation of Earth on its axis

Tides are caused by the...

Gravity of the sun and moon

High tides are created on Earth when nearby celestial bodies create what change in the oceans?

Gravity pulls on the water creating bulges on two sides of Earth

Which of the following statements regarding the schedule of high and low tides is correct?

In a 24 hour period, a geographic location can expect 2 high tides and 2 low tides

Explain the location of celestial bodies in a lunar eclipse v. Solar eclipse.

In a Lunar eclipse a celestial body are on the sides

Spring tides: - occur when the Sun, Earth, and Moon align in a straight line - cause very high tides and very low tides

Neap tides: - occur when the sun, earth, and moon form a right angle - cause tides with the smallest difference between high and low tides

Spring tides occur during...

New and full moons

Newton's Law of Universal gravitation also states that the larger the object, the greater the force of gravity excreted by that strength.The Sun is much larger than the Moon, yet it is the gravitational pull from the moon that has the most effect on the surface waters of Earth. This occurs because the strength of the force of gravity is affected by the distance between the two objects. Since the Moon is much closer to Earth than the Sun, the Moon's gravitational force has a greater effect on ocean tides. The gravitational pull from the Sun does have some effect on the ocean tides especially in the formation of spring and neap tides.

The combination of the daily rotation of Earth and the 27.3 day revolution of the Moon around Earth results in a predictable pattern of rising and falling tides or high and low tides. High tides occur on the part of Earth located in a direct line with the Moon, while low tides occur in waters is located at right angles to the direct line of the Moon. Since the occurance of the tides is a result of the position of the Moon relative to Earth, a schedule of when high tides and low tides will occur can be predicted using the lunar cycle.

What object has the greatest effect on Eartj's oceans?

The moon

True/ False Tides mainly affect rivers and lakes.

True

The gravitational pull from the Moon affects all of the waters of Earth, but as we remember from Newtons Law, the larger the body, the greater the gravitational attraction. This is true for the body being attracted as well. Bodies of water that are smaller than oceans, seas, and large lakes are pulled by the Moon's gravity, but the reaction is so small that we are not able to see it. The effect of the pull of gravity on large bodies of water can be seen in the rising of the waters to form high tides and the falling of the waters or low tides.

When the water bulges from the gravitational pull, the waters are at high tide. High tides are the greatest length inland a body of water reaches. The waters in the area not affected by the pull are at low tide. Low tides are the lowest point on land a body of water reaches as it recedes.