Thursday, December 19, 2013

Tides and the Moon

     Tides are caused by a gravitational tug-of-war between the sun, moon, and earth. All objects exert gravitational pull on each other. The closer they are, or the larger they are, the greater the pull. All of the planets exert some gravitational pull on the earth. However, the pull of the moon and sun are most noticeable because the moon is so close to us and the sun is so big. It takes the earth 365 days to revolve around the sun. As it revolves around the sun, it spins, or rotates on its axis once every 24 hours. At the same time, the moon revolves around the earth once every 29 days. The gravitational pull of the sun holds the earth in orbit, while the gravitational pull of the earth keeps the moon in orbit.As a result of this gravitational attraction between the earth and the moon, the side of the earth facing the moon is pulled towards it. Solid objects like the ground and buildings are not distorted as much as liquids like the ocean. A bulge of water occurs on the side of the earth facing the moon. As the earth rotates around the sun, centrifugal force causes an equal bulge of water on the opposite side of the earth. Water is pulled away from these two sides of the earth to form these bulges, or high tides. This leaves a depression, or low spot, in the oceans between. These are the
areas of low tides.

Friday, December 6, 2013

Global Wind Patterns

1.)Earth has uneven heating because of the earths titled axis, sphere shape, and earths rotation.The angle at which the sun's rays strike the earth's surface is a major factor in the amount of energy received per unit of surface area. More direct rays provide more concentrated energy. Sun angles are also useful in navigation for determining latitudinal position.

From the global winds lab i learned about all the different wind patterns there are. They all have different wind directions as well as rotations. Not one wind pattern is the same. 

2.)The earths rotation affect the air and water masses by the Coriolis Effect. The Coriolis force is quite small, and its effects generally become noticeable only for motions occurring over large distances and long periods of time, such as large-scale movement of air in the atmosphere or water in the ocean. The Coriolis Effect is an effect whereby a mass moving in a rotating system experiences a force acting perpendicular to the direction of motion and to the axis of rotation. A Hadley Cell is a large-scale atmospheric convection cell in which air rises at the equator and sinks at medium latitudes, typically about 30° north or south. Deserts are at 30 degrees latitude because The equator has more heat than the North and South poles. Air sinks at the poles and rises at the equator, sinking air causes drying which is what deserts are all about. Deserts by definition are places which receive very little rain every year.

3.)Prevailing winds are winds that blow predominantly from a single general direction over a particular point on the earths surface. Trade winds are winds blowing steadily toward the equator from the northeast in the northern hemisphere or the southeast in the southern hemisphere, esp. at sea. Doldrums are a state or period of inactivity, stagnation, or depression. Horse latitudes are a belt of calm air and sea occurring in both the northern and southern hemispheres between the trade winds and the westerlies.The Westerlies are the prevailing winds in the middle latitudes between 30 and 60 degrees latitude, blowing from the high pressure area in the horse latitudes towards the poles. I didnt realize there were so many different wind patterns i thought that there were different patterns of wind everyday.Prevailing westerlies in the Northern Hemisphere are responsible for many of the weather movements across the United States and Canada.

They expect that as global warming continues, the temperature difference between, say, the equator and the North Pole is expected to shrink, because the Arctic is warming much faster than the tropics.