SDI Open Water Scuba Diver Practice Exam

What causes surge in water?

1. Wind patterns

2. Back-and-forth movement of water caused by passing over head

3. Earthquakes under the sea

4. Tides changing

The correct answer is: Back-and-forth movement of water caused by passing over head

Surge in water refers to the powerful and oscillating movement of water, typically observed in coastal areas as waves roll in and out. This phenomenon primarily results from the back-and-forth movement of water caused by waves crashing near the shore. When waves approach the coastline, they can become larger and more forceful due to the shallow water. As these waves break, they push water onto the land, and the water must return back to the ocean, creating a surge effect. The understanding of surge is crucial for divers and swimmers, as it can significantly affect visibility and control while in the water. Recognizing this movement helps in anticipating how water will behave when approaching the shore or while diving in areas where surge is prevalent. Other factors mentioned, such as wind patterns, earthquakes, and tidal changes, contribute to various ocean phenomena but do not specifically cause surge. Wind patterns affect wave formation and can influence ocean currents, earthquakes generate tsunamis which are different from surge, and tidal changes affect water levels rather than causing the oscillating motion characteristic of surge. Thus, the reason for selecting the back-and-forth movement of water caused by waves as the cause of surge is based on its direct relationship with the dynamics of wave action near the shore.