ALTERNATIVE ENERGY VS GLOBAL WARMING AND CLIMATE CHANGE (Target Oriented to Out)

Energy is very important to the climate system. It is energy which drives the system and is constantly being exchanged from one component lo the next. Energy is defined as the ability to do work and in physics work occurs when an object moves over some distance due to force acting along the line of the movement. Scars, Zemansky and Young put forward the following example of work. Supposing someone asked you to move a heavy box for them. If you were to push it along a level floor you would be exerting a force on the box and causing it to move. Some component of the force would be directed in the direction of motion; this is work as defined in terms of physics. However, if you picked up the box and carried it yon might well think that you were working hard but in physics terms work would only have been done when you picked up and put down the box. While carrying the box no work will have been done as the supporting force [supplied by you!] is in the verti¬cal while the box is moving horizontally. In this case there is no component of the force acting m the direction of movement.

Energy comes in lots of different forms and it can transform from one type to another. A system has an energy budget and because energy can neither be created nor destroyed, the amount of energy gained by the system must equal the amount of energy lost plus any change in the stored energy of the systems.

Potential energy is the amount of energy stored by an object. There are various different forms of potential energy. Gravitational potential energy is the energy an object possesses due to its position. It depends on mass, grav¬ity and height. Essentially the higher and heavier an object is, the more potential energy it has. Chemical potential energy is the work that can be done due to a chemical change within a substance. The energy we get from food is stored as chemical potential energy. Similarly, fossil fuels have chemical poten¬tial energy which is transformed to provide heat.

Kinetic energy is the energy that an object possesses due to its movement. It depends on both the mass of the object and its speed. Objects moving at a higher speed have a higher kinetic energy than those moving at slower speeds. Those objects which have more mass have a greater kinetic energy than those with less mass. In a cup of water, where some molecules will be moving faster than others, there will be a range of speeds and hence a range of kinetic energies.

Temperature is defined as the mean kinetic energy per molecule of all the molecules in an object; in essence the average speed of die molecules of a sub-stance. Temperature can be measured on a variety of different scales and the two used internationally are Celsius (also called centigrade} denoted by C and Kelvin denoted by a K. The intervals on these two scales are the same that is a temperature rise of 1 C is equivalent to a rise of 1 K, The definition of the zero points, however, are different on each scale. On the Celsius scale0 C is the freeing point of water whereas on the Kelvin scale 0 K (around -273.15 C) is defined as the temperature at which all molecular motion stops. Bohren states that it is more true to say that matter ceases to radiate, rather than motion ceases. Only in an ideal gas would motion stop. An ideal gas is, a hypothetical one, where the molecules are far enough apart so as not to interact with each other. The atmosphere approximates to an ideal gas at room temperature. At absolute zero (0 K), quantum, rather than classical mechanics takes over any object above 0 K will have kinetic energy. Internal energy is the amount of kinetic and potential energy the molecules of an object contain.

Energy can be transferred by the means of work. This would occur if a mechanical force was used to compress a gas. Once compress the gas tan do more work so energy has been transferred to it through work. An example of this is a bicycle pump. You provide a mechanical force which compresses the air in the pump, causing it to become hotter, increasing its amount of kinetic energy. Another way in which energy is transferred from one object to another is by heat due to a temperature difference. The result of this energy transfer will be changes in the properties of the object. The temperature may rise or the object may change state (as energy is being added the state change will be 10 a higher one from solid to liquid or liquid to gas) or both. A tem¬perature rise is referred to as sensible heat exchange whereas a change state is known, is latent (hidden) heat.

Specific heat capacity is the heat required to raise the temperature of 1g mass of a substance by 1C. Different substances require different amounts of heat to raise their temperature by 1C. The term calorie (cal) is defined as the heat needed to raise 1g of water from 14.5 C to 15.5 C. The specific heat capacity of water is taken to be 1 cal g (C). Soils have a much lower spe¬cific heat capacity than water (about 0.2. call). Consequently although water takes longer to heat up than the land, it also takes longer to cool down. This property has an effect on the world's climate. The interior of continents such as Europe and Asia experience much more extreme summers and winter s than coastal regions. AT the coast the oceans act as a thermal score, smooth¬ing out the difference between winter and summer.