October 4, 2017 at 9:45 am #3785
In connection with Part 3 of this lesson, “How and Where Does Energy Travel?”, kids may ask about “renewable energy”. Admittedly, the term implies that there is a special form of energy or at least a way in which energy, can be refreshed and reused. Emphasize that such a notion is false. As described in the lesson, energy can only flow “downhill” toward a cooler place. “Renewable” is the wrong term; the word to use should be “inexhaustible”. No matter how much we use, these sources will not run out.
These inexhaustible sources of energy are wind energy, water power, e.g., hydroelectric dams, and direct conversion of sunlight to electric power via photovoltaic (solar) cells.
Type into your browser: renewable energy images
As well as direct use of sunlight via solar cells, note that wind and water power are also solar energy since it is solar heating of the atmosphere that is responsible for wind and solar heating of water that drives the water cycle leading to water power. Of course, virtually all life on Earth runs on solar energy as is drives photosynthesis. Astronomers have calculated that the sun will continue emitting energy much as it is now for hundreds of millions of years into the future, far beyond what is conceivable on the human time scale. And, it will make no difference in the sun whether or not or how much of its energy we harness. Therefore, these sources of energy are referred to as “renewable” although “inexhaustible” might better convey the concept.
Currently, the largest portion of our energy still comes from fossil fuels: coal, crude oil (refined into gasoline, fuel oil, etc.) , and natural gas. There are limited deposits of these materials in the Earth’s crust and they are not being replenished. Therefore, they are known as nonrenewable. Most concerning at the present time, however, is the fact that burning these fuels results in adding carbon dioxide to the atmosphere, which is resulting in climate change (warming). (This cannot be avoided. All of these fuels are based on carbon molecules. The energy released in burning comes from oxygen combining with carbon to produce carbon dioxide.) Other pollutants are produced as well. Thus, the push nowadays is to move toward obtaining energy from those sources that are everlasting, inexhaustible, and nonpolluting, namely solar power and wind power.
I welcome further comments. Bernie Nebel
September 5, 2020 at 3:26 pm #8398
Great information! Thank you!
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