Give short answers for the following questions. (20-30 words)
1. What are the main sources of freshwater? 2. What is tidal energy?
3. What is a tsunami?
4. What causes the formation of waves?
5. What is an ocean current?
Answers
1. The original source of almost all fresh water is precipitation from the atmosphere, in the form of mist, rain and snow.
2. Tidal energy is power produced by the surge of ocean waters during the rise and fall of tides. Tidal energy is a renewable source of energy.
3. Tsunamis are giant waves caused by earthquakes or volcanic eruptions under the sea. They speed along as fast as jet planes.
4. Waves are most commonly caused by wind. Wind-driven waves, or surface waves, are created by the friction between wind and surface water. As wind blows across the surface of the ocean or a lake, the continual disturbance creates a wave crest. The gravitational pull of the sun and moon on the earth also causes waves.
5. Ocean currents are the continuous, predictable, directional movement of seawater driven by gravity, wind (Coriolis Effect), and water density. Ocean water moves in two directions: horizontally and vertically. Horizontal movements are referred to as currents, while vertical changes are called upwellings or downwellings.