Ocean Tides and Gravity Effects

Study Notes

Tides are the regular rise and fall of ocean and lake water levels
Tides are caused by the gravitational forces of the Sun, Earth, and Moon
The Moon's gravity affects Earth's water more than the Sun's, despite the Sun's greater mass, because the Moon is closer to Earth

Earth rotates on its axis once a day
The Moon revolves around Earth in about 28 days
Earth revolves around the Sun in about 365 days
Gravitational forces between the objects affect each other
Gravitational force depends on the mass of the objects and the distance between them
The Moon's gravity is stronger on Earth than the Sun's, even though the Sun is much larger, due to the Moon's proximity to Earth.
Ocean water is affected more by the Moon's gravity than the Sun's

High tides occur on the side of Earth facing the Moon and on the opposite side
Low tides occur at right angles to the high tides
These are caused by the Moon's gravity pulling water toward it and by inertia (the tendency of objects to resist changes in motion)
Tides move around the Earth as it rotates, resulting in a cycle of high and low tides

Spring tides occur when the Sun, Earth, and Moon are aligned
This alignment amplifies the gravitational forces, leading to higher high tides and lower low tides

Neap tides occur when the Sun, Earth, and Moon form a right angle
This reduces the gravitational forces, leading to less difference between high and low tides

The range between high and low tides varies throughout the year
The greatest difference in high and low tides occurs around January 2, when Earth is closest to the Sun in its elliptical orbit
The smallest difference in high and low tides occurs around July 2, when Earth is farthest from the Sun in its elliptical orbit

Tidal power plants use the kinetic energy of rising and falling tides to generate electricity
Turbines convert the energy of the moving water into electricity