Monthly Archives: August 2009

Energy Conservation, Conversion, and Windmills

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What is a Generator?

When a magnet moves toward a metal object, the electrons in the metal move. As a result, when a magnet moves near a copper wire, electrons in the copper move. Generators use this principle to convert mechanical energy (the rotation of a wire coil,or rotor around a magnet) into an electrical current (electrons flowing through the wire). A motor performs the opposite function by converting electrical energy into mechanical energy. For the most part, all generators work the same. The item that separates them is, “What turns the rotor?”

Windmill Generator Kit

Windmill Generator Kit

Energy Conversion in a Windmill

Obviously, in a windmill, the wind is rotating the wire coil around the magnet. This generator is taking the kinetic energy from the wind and converting it to electrical energy.

Windmills are rated based on output power (watts), working voltage (volts), start up windspeed (mph), survival wind speed (mph), rated rotation of the blades (rpm) and the diameter of the blades (also called the rotor). In general, the larger the rotor diameter the more wind that is intercepted and the more electricity produced. There are do-it-yourself plans available for building your own windmill. No waste or pollution is produced during this process.

When discussing this in the classroom or entertaining your children on the weekend, there are some small demonstration kits available. The Windmill Generator from 4M Kidz Labz TM is an excellent activity.

The Nitrogen Cycle

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Nitrogen is found throughout the soils and atmosphere in many different, organic and inorganic, forms. The Nitrogen Cycle is the process by which atmospheric nitrogen enters the soil, is transformed by microbes, and re-enters the atmosphere (volatilization) and plants (assimilation).

How Does Nitrogen Enter the Soil?

Before nitrogen can be used by plants, it must enter the soil. Atmospheric nitrogen is forced to the ground by rainfall. Also, urine, solid and liquid waste from living organisms and living organisms that have died are deomposed by bacteria and fungi. The nitrogen from these sources then enter the soil. Commercial fertilizers are another source of nitrogen.

What Happens to Nitrogen in the Soil?

Plants cannot use organic nitrogen. Bacteria and fungi are needed to transform this unusable organic nitrogen into a usable form. Although most nitrogen fixation is completed by bacteria, some is accomplished through lightning strikes. Since ammonia is fatal to most plants, bacteria convert this ammonia (NH4) into nitrates (NO3) and nitrites (NO2). At this time, the nitrogen can be assimilated into the plant, leached into the ground water or be transformed into a gas and re-enter the air.

In very wet soils, the oxygen content is low. The bacteria in these soils take the oxygen out of the nitrates (NO3) and produce nitrogen gas. This process is call denitrification. Through a process called volatilization, the gas re-enters the atmosphere.