Movement There are many different types of movement that take place at Makaha Beach. The major movements in a shoreline ecosystem would include currents, tides, and waves. Have you ever wondered why you drift when you're at a beach but you haven't even moved? How waves can basically come from out of no where? Or why one time you go to a beach and there's a big rock exposed, then the next time you visit the rock is covered with water? Well this section of my website will answer questions like these. |
High Tides and Low Tides A tide is a rise and fall in sea level. Tides mainly caused by the interaction of gravity in the Earth-Moon system. The Moons gravity gives off a strong pull on Earth. Then Earth and the water on Earth respond to this pull. A rise in sea level is called a high tide, and a fall in sea level is called a low tide. The tidal range is the difference between the level of the ocean at high tide and the level of the ocean at low tide. There are also spring tides and neap tides. Spring tides is when the Sun, Moon, and Earth are aligned. During this time, high tides are higher then usual and low tides are lower then usual. Neap tides is when the Sun, Moon, and Earth form a right angle. During neap tides high tides are lower then usual and low tides are higher then usual. These tides are very important in Hawaiis ecosystems.
|
This picture shows Makaha beach at high tide with waves. |
This picture shows Makaha Beach at low tide. |
Currents There are various types of currents. These types include surface currents warm and cold surface currents, and density currents. Surface currents are powered by winds. They move water horizontally or parallel to Earth's surface. These winds, force the ocean to move in large circular patterns. There are also warm and coldl surface currents. This is when warmer surface currents distribute heat from regions near the equator else where. There are also upwellings. This is when a circulation in the ocean brings deep, cold water to the ocean surface. Lastly there are density currents. These currents form when a mass of seawater becomes more dense then surrounding water and sinks. The dense water then slowly spreads throughout the rest of the ocean. This type of current circulates water slowly. |
Waves A wave is a rhythmic movement that carries energy through matter or space. In our case the waves at Makaha Beach move through seawataer. There are multipule areas on a wave. First there's the crest, the crest is the highest point of the wave. Then there's the trough, the lowest poin on a wave. To measure wavelength you must measure the distance between the two crest or trough of two adjacent waves. When a wave is created it doesn't move forward. The energy that created the wave moves forward while the water remains in the same spot.
Waves can be created by winds. This happens when wind blows across a body of water and causes friction which moves the water along with it. When the speed of the wind is great enough then water is able to pile up and form a wave. As waves reach shore, the wavelength decreases and the wave hieght increases. When this happens waves break.
|
