¶ … Speech for How Solar Energy Works Specific purpose: To inform listeners how solar energy offers a beneficial source of renewable clean energy

Central idea: Using solar energy offers a realistic source of clean energy, but governments and people must be willing to make the necessary changes to use it.

Informative speech: How solar energy works

Solar energy is perhaps the oldest form of power ever used by human beings. People have used the energy derived from the sun to light their homes; grow crops; tell time; and guide their lives since human civilization began. However, solar energy has only recently become regarded as a potentially feasible way of dealing with the nation's energy crisis. This paper will describe how solar energy works, why it is so potentially beneficial for humankind, and some cultural obstacles to using solar energy.

On a very basic level, houses can be redesigned to better use solar heat. "Simple design features such as properly orienting a house toward the south, putting most windows on the south side of the building, skylights, awnings, and shade trees are all techniques for exploiting passive solar energy" (How solar energy works, 2012, Union of Concerned Scientists). Large, flat boxes painted...

On a wider scale, using mirrors and lenses to concentrate the rays of the sun can be used to actually power industrial applications. This can be achieved through the use of "parabolic troughs -- long, curved mirrors that concentrate sunlight on a liquid inside a tube that runs parallel to the mirror. The liquid, at about 300 degrees Celsius, runs to a central collector, where it produces steam that drives an electric turbine" and can produce heats up to 3,000 Celsius (How solar energy works, 2012, Union of Concerned Scientists). A similar type of application, that of parabolic dish concentrators, generate even more heat because their design enables more concentrated focus of the energy that is created through the shape of the dish. Another promising source of solar energy is that of photovoltaics (PV) systems connected to the electric grid. "The most important components of a PV cell are two layers of semiconductor material generally composed of silicon crystals" which creates an electric spark when exposed to sunlight (How solar energy works, 2012, Union of Concerned Scientists).
Because solar energy is an inexpensive and renewable…