some wave photos! waves the most common cause is wind. As wind passes over the water's surface, friction forces it to ripple. The strength of the wind, the distance the wind blows (fetch) and the length of the gust (duration) determine how big the ripples will become. Waves are divided into several parts. The crest is the highest point on a wave, while the trough, or valley between two waves, is the lowest point.Wavelength, the horizontal distance, either between the crests or troughs of two consecutive waves. Wave height is a vertical distance between a wave's crest and the next trough. Wave period measures the size of the wave in time. A wave period can be measured by picking a stationary point and counting the seconds it takes for two consecutive crests or troughs to pass it. We can describe breaking waves in three different ways: Surging Breakers, Plunging Breakers and Spilling Breakers. You see examples of these at the beach. Surging Breakers happen on beaches where the slope is very steep. The wave does not actually break. Instead, it rolls onto the steep beach. These kinds of breakers are known for their destructive nature. Plunging Breakers happen on beaches where the slope is moderately steep. This kind of wave normally curls over forming a tunnel until the wave breaks. Expert surfers love this type of wave! Spilling Breakers occur on beaches with gentle slopes. These waves break far from the shore, and the surf gently rolls over the front of the wave. tides Tides are the periodic rise and falling of large bodies of water. Winds and currents move the surface water causing waves. The gravitational attraction of the moon causes the oceans to bulge out in the direction of the moon. Another bulge occurs on the opposite side, since the Earth is also being pulled toward the moon (and away from the water on the far side). Ocean levels fluctuate daily as the sun, moon and earth interact. As the moon travels around the earth and as they, together, travel around the sun, the combined gravitational forces cause the world's oceans to rise and fall. Since the earth is rotating while this is happening, two tides occur each day. The gravitational force of the moon is one ten-millionth that of earth, but when you combine other forces such as the earth's centrifugal force created by its spin, you get tides. The sun's gravitational force on the earth is only 46 percent that of the moon. Making the moon the single most important factor for the creation of tides. The type of gravitational force that causes tides is know as "Tractive" force. Because of the complex dynamics of the Earth's oceans, their inertia, friction with the ocean floor, internal viscosity and the distribution of the continents, the maximum tides do not always coincide with the optimal times of proxigee. Still, these tides can produce enormous damage when all factors come together optimally. If the Moon were to escape, what would happen to the Earth's oceans? "What happens is that the lunar water tides on the Earth go away, but the solar water tides still occur, but with about 1/3 or so the amplitude. There are still daily high and low tides, but they would be noticeably smaller. tide types Spring tides are especially strong tides (nothing to do with the season Spring). They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides. Spring tides occur during the full moon and the new moon. The Proxigean Spring Tide is a rare, unusually high tide. This very high tide occurs when the moon is both unusually close to the Earth (at its closest perigee, called the proxigee) and in the New Moon phase (when the Moon is between the Sun and the Earth). The proxigean spring tide occurs at most once every 1.5 years. Neap Tides Neap tides are especially weak tides. They occur when the gravitational forces of the Moon and the Sun are perpendicular to one another (with respect to the Earth). Neap tides occur during quarter moons. ^*^