Electricity

Electricity is the flow of free electrons through a conductor. Each of these free electrons jumps from one atom to another within the conductor. A free electron is an electron lost by an atom in the material conductor an is drawn towards another atom which has already lost one, thus giving rise to a continuous flow of electrons from atom to atom within the material the conductor is made of.

All matter is made up of atoms. An atom has protons, which are positively charged, in its nucleus, and the same amount of electrons orbiting about the nucleus. As electrons are negatively charged, an atom is in equilibrium, or balanced, when it has not lost an orbiting electron. When an atom has lost an electron, it becomes a positive +ion, since it contains more protons than the negatively charged electrons. When it has gained one, we call it a negative -ion, since it now has more negatively charged electrons than positively charged protons. So, when one atom loses an electron, it will always tend to draw, or gain, a new one towards itself to recover its internal equilibrium.

Not all materials allow this constant flow of electrons when the conditions for which are created. There are good materials and bad ones. The materials which allow the flow of electrons are called conductive materials. Those that do not allow are called non-conductive materials. For example, metals are excellent conductors, specially aluminum and copper. On the other hand, materials such as wood, glass, and plastic are non-conductive materials, or insulating materials.

In electricity this flow of electrons within a conductor is called electric current. And there are two kinds of electric current. Direct current and alternating current.

Ocean Current

An ocean current is any of the number of river-like, moving masses of water flowing in all oceans, each having a characteristic direction, length, depth, speed, and temperature. This great flow of global conveyor belts is caused by the planet rotation, the gravitation of the moon, the wind, temperature, and salinity differences. Warm ocean currents are corridors of warm water moving from the tropics poleward where they release energy to the air. Cold ocean currents are corridors of cold water moving from higher latitudes toward the equator where they absorb the energy received in the tropics as they cool the air above.

Although some ocean currents result from density and salinity variations of water, the major ocean currents are wind-driven currents. Surface currents make up about 10% of all the water in the ocean. These waters are the upper 400 meters of the ocean. Deep water currents make up the other 90% of the ocean; these waters move around the ocean basins by density driven forces and gravity. Density difference is a function of different temperatures and salinity.

Ocean currents can flow for thousands of kilometers. They are very important in determining the climates of the continents, especially those regions bordering on the ocean. Perhaps the most striking example is the Gulf Stream, which makes northwest Europe much more temperate than any other region at the same latitude. Another example is the Hawaiian Islands, where the climate is cooler than the tropical latitudes in which they are located because of the California Current.