Solar Energy
From Wikibooks, the open-content textbooks collection
Energy is the ability to do work. We eat, travel, do our job, socialize with people, none of these things can happen without energy. Most of the energy use today are direct or indirect forms of solar energy.
The food we eat comes from plants or animals. Plants convert light from the sun into carbohydrates and tissue. We eat pants (rice, wheat, corn, potatoes) which are foods from plants. Animals we eat such as cove, goat, fish get their energy by eating plants. So its safe to say all food we eat are produced from solar energy.
We fill our tanks with gas, most of our power stations runs on coal. Petroleum is nothing but remains of dead animals that once existed millions of years ago. Coal are remains of trees and forest that once flourished under sunshine. So the power we get from gas and coal are nothing but indirect forms of solar energy.
Solar energy was harvested and used by our ancestors for along time. For example we dry clothes on the out doors. The sun shines on it, heat it up and quickens the pace at which water evaporates from the clothes. Mayans used mirrors to start fire using parabolic mirrors. to concentrate sun rays into a tiny spot on tinder. The tinder will get hot enough and burn, thus it could be used to start fire. Glass houses are being used in cold climatic region to keep crops from freezing by trapping warmth giving the sun inside a glass structure.
Contents |
[edit] How does the Sun produce power?
[edit] Potential of solar energy
[edit] History of solar energy
The history of solar energy is fascinating and awe inspiring. We humans have taken the Sun as granted. We have used Solar Energy even before we realized we were using it. But even before us animals and plants have been using the energy of the Sun millions and millions of years ago.
[edit] Life depends on solar energy
Almost all life on Earth is directly or indirectly dependent on solar energy. The abundance of Sunlight has made rain forest flourish, has made the windows to blow, rains to occur, rivers and streams to flow.
So which life started to use the power of the Sun? The answer probably is plants. Plants use a unique chemical process called photo synthesis. They take in carbon dioxide and water, use solar energy to convert it to carbohydrates and oxygen. The oxygen is released as a byproduct into the atmosphere. In other words plants convert light energy into chemical energy which is used for it to function like creating more leafs, wood, bark, fruits, seeds and so on.
Animal's use solar energy. Animal skin uses sunlight to produce vitamin D which is responsible for healthy bones. The mos visible use of solar energy or light is for vision. Many animals can see with their eyes which detect light.
Ants use the position of Sun as compass and they navigate accordingly. The sun does not stay in the same spot in the sky, but ants some how are able to use the position of Sun to navigate.
Cold blooded animals like crocodiles bask. This enables then to quickly raise their body temperature which enables them to be active. Even warm blooded animals position them self to receive maximum sunlight at dawn for their body to warm up a bit.
[edit] Humans use solar energy
Humans were quick to adopt the use of solar energy. Perhaps the first application they directly used it could be for drying. It could have been drying meat, fish, washed clothes or perhaps to dry themselves when they are wet. The next purpose could be to get warmth of the sun in colder climates and seasons.
Humans really started harvesting solar energy when they started to grow crops. Many civilizations realized sunlight is a vital component for crop growth. For example farmers in the state of Tamil Nadu India celebrate a festival called Pongal on January 14th of every year. Pongal is a way of thanking the sun for aiding the farmers in agriculture and on their quest for a good harvest.
Egyptians worship the Sun as God named Ra. Mayans respect the Sun and have gone to the extent of sacrificing humans so that the Sun would rise everyday without fail. Mayans were the first to use solar concentrators. They used a highly polished parabola to concentrate sunlight into a tiny spot so that it could light a tinder to make a fire.
Many cultures feared eclipse as they thought Sun was in trouble and could be doomed. Sun was clearly important to ancient civilizations. Though they never understood what Sun is made of, they knew sun was important and they could be doomed if the sun was doomed.
