16.2 Waves and Tides

Wave Height

• The vertical distance between the trough and crest of a wave.

Wavelength

• The horizontal distance separating trough and crest of a wave.

Wave Period

• The time interval between the passage of successive crests at a stationary point.

Fetch • The distance that the wind has traveled

across open water.

Tide • Daily change in the elevation of the

ocean surface.

Tidal Range

• The difference in height between successive high and low tides.

Spring Tide

• Highest tidal range that occurs due to the alignment of Earth, the moon, and the sun.

Neap Tide

• Lowest tidal range, occurring near the times of the first-quarter and third-quarter phases of the moon.

Key Concept

• From where do ocean waves obtain their energy?–Most ocean waves obtain their energy

and motion from the wind.

Key Concept

• What three factors affect the characteristics of a wave?–The height, length, and period that are

eventually achieved by a wave depend on three factors: wind speed, length of time the wind has blown, and fetch.

Key Concept

• How does energy move through a wave?–Circular orbital motion allows energy

to move forward through the water while the individual water particles that transmit the wave move around in a circle.

Key Concept

• What causes tides?–Ocean tides results from differences in

the gravitational attraction exerted upon different parts of Earth’s surface by the moon and, to a lesser extent, by the sun.