Why are there waves in the sea?
Waves are generated by a number of things. One of them is the currents, where oceanic currents affect the movement of the water and this has a rippling effect. The closer the resultant ripples get to the coastline where the water is typically shallower, the larger the ripples and this is witnessed as waves. Another generator of waves is tides. As the tides rise and fall, the body of water moves and creates ripples and waves. Wind also creates waves. The movement of air disturbs the surface of water and this results in ripples. Accumulatively over many miles the magnitude of the waves gets larger, and again, where the water gets shallower near the coast, the waves gain amplitude (size). Movements in the earth’s crust under the sea also creates waves. This is what a tsunami is – large waves created by sudden movements in the earth’s surface under the sea, typically by way of earthquakes. Other tremors, and underwater volcanoes also can have the same effect. Also, earthquakes with an epic
Waves found in the ocean have different causes and, therefore, different characteristics. At the surface of the ocean, waves can be generated by the action of wind blowing across the surface, by earthquakes beneath the surface of the ocean, by changes in atmospheric pressure or along its shores or by the gravitational attraction of the sun and moon. Normally these waves transmit energy only, not matter. Progressive waves show both longitudinal (back and forth) movement and transverse (right angle) movement. This resultant is called orbital movement. If we observe waves from a fixed point we see troughs and crest passing by. The distance fromm successive crests or troughs is called the wavelength (L). The time interval for the passage of one wavelength is called the period (T). If we know either one, the other can be calculated from the equation because the theoretical relationship is known – L = 1.56T2: Speed (S) = L/T = 156m/10s = 15.6m/s Wave Steepness = H/L Frequency (f) is the numb
