Homework Help: Science: Earth: Water

When you first think of the word water, it probably reminds you of drinking water from your sink. Instead, here we will be discussing oceans, seas, lakes, seas, rivers, and much more. As you probably already know, without water, nothing lives. Earth is almost 75% covered with water, which is why there is so much life on Earth! And don't forget about all of the water floating around in the air, not to mention all of the underground water!

First, let's talk about the largest bodies of water, the oceans. The four main oceans are the Pacific, Atlantic, Indian, and Arctic Oceans. All of them are connected to each other one way or another. They share waves and tides, and many species that live in the oceans migrate from one ocean to the next.

Under these oceans is in fact almost a whole underwater world. Under the water just beyond land is the continental shelf. This is the shallowest part of all bodies of water. After the continental shelf come the abyssal plains, which are even deeper. Many times, on the abyssal plains, there are underwater mountain ranges. Sometimes, these mountains have active volcanoes! Toward the very middle of the oceans are ridges. These are very small 'hills' that are usually made of sand. They were created by water currents over periods of time.

The ocean is divided into three layers. The top layer of the ocean is called the photic layer. The middle one is called the bathyl layer. And last, the very deepest one is called the midnight layer.

You probably already know there are an infinite number of waves and currents out there, but you may be more surprised to hear that each one is caused by winds. Winds cannot reach deep waters, but those waters still have currents because there is icy polar water down there that moves and causes those currents. Logically, the stronger the wind, the larger and stronger the wave and its current. Also, the longer the wind blows, the larger and longer the wave will be!

Waves may not seem like complex topics to learn about, but there are people out there constantly studying waves and their movement. All waves have wavelength, wave-height, crests, and troughs. Wavelength is simply the length of the wave, and wave-height is logically the height of the weight. The crest is the top point of water in between two waves, and trough are the very bottom part at the center of the wave. In other words, a crest is in between two troughs, and a trough is in between two crests!

Tides are not waves, but instead are the movement of water within bodies of water that are not cause by wind. Instead, they are cause by the moon's gravity! In other words, as the moon moves around the Earth, the tides move around the Earth as well.

There are four different kinds of tides: the ebb tide, flood tide, spring tide, and neap tide. The ebb tide is the lowest tide there is, when the tide is right next to the shore at almost the exact same level. Flood tide is a obviously higher, when the water is at its highest point along the shore. Even higher is the spring tide which occurs only twice a month. A spring tide occurs when the moon and sun are both lined up to the Earth, and therefore but the sun's and moon's gravity pulls on the water, causing a spring tide to occur. Last, neap tides occur during half-moons when the sun and moon are at right angles to the Earth, and the sun reduces the amount of gravity that the moon has.

Homework Help: Science: Earth

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