Thursday, January 12, 2012

Solar Powered Cars

Solar cells are capable of producing a reasonable amount of electric energy from solar light. This has stimulated the imagination of many creative people around the world.

One of the most attractive uses for the photo electricity –electricity produced by light– are the vehicles powered by solar energy. So far, tests on airplanes, boats and cars have been performed with different results. A light airplane, which had all the roof covered by solar cells capable of producing enough energy to move an electric engine, was able to fly over the English Channel. 

Each year on Australia an original race is celebrated where only solar powered cars run. The participants have to travel from side to side the Australian continent and most of them don’t finish. The average speed accomplished by these cars is between 50 and 80 Km per hour.

The disadvantage of vehicles directly powered by photovoltaic cells is that they only work well on places with a exceptionally clear and sunny weather.

As usually happens on the high technology business, Japan is one of the pioneers on solar energy applications to transportation. The main inconvenient of using solar energy on vehicles is the necessity of using heavy accumulators or batteries that occupy too much space. This is because of the need of store energy for the vehicle when there is no solar light available. The batteries store the energy when solar light is abundant.

A possible dream 

In the 60’s, experts around the world worked in a project that could look as science fiction. It involves launching an enormous space station to convert solar energy into electricity and send it to the earth in form of microwaves.
The space station would have 3 main parts: a solar collector of 6 Km long by 2.5 Km width, build of mirrors and photovoltaic cells; a energy central and a microwave transmitter. Despite its cost, an installation of this magnitude could be rentable on the long run thanks to the fact that the energy efficiency of solar cells is higher outside the earth’s atmosphere. This microwaves could be transformed into electricity again on earth. 

The microwave transmitter space station project has never go further than in paper, many hoped that this could have been the end of the fossil fuels. Nevertheless, some day we could have to give a chance to these exotic and crazy methods to obtain efficient energy for men.

Monday, January 2, 2012

Solar Energy

The solar light is very important for the life on earth. It’s one of the most important world energy resources used by plants and seaweeds to transform the nutrients to grow. The oxygen we breathe is released in the process.

The plants absorb water and minerals through the roots that end up in the leaves thanks to a network of small conducts. The leaves absorb Carbon dioxide from the air and, with the help of these 3 substances –water, minerals and Carbon dioxide– the plants build their tissues. To be able to do so they need energy, the same as we do for your foods. The energy the plants use is the solar energy they get and transform it through the process of Photosynthesis

The photosynthesis

Photosynthesis process in the plantsThe leaves of all plants have a green substance called chlorophyll that is used to retain light energy. This energy allows them to separate the Carbon and Oxygen from the Carbon dioxide and combine the carbon with the water and minerals stored in the leaves. The results of these combinations are the sugars and starches that are the majority of the nutrients of the plants. The oxygen is free and released during the process. This all together is the process of Photosynthesis. That’s why reforestation projects must be put in practice to help reduce carbon dioxide in our atmosphere.

The humans benefit from the solar light too
We need the light energy, among other things, to produce an essential vitamin for our growth and conservation of our bones and teeth: The vitamin D. Our body produces this vitamin, in the skin, through a similar process to the photosynthesis of the plants.

An excess of light can be dangerous
A part of the solar energy, the ultraviolet radiation, can seriously harm the living things but, luckily, the largest part of all the radiation doesn’t get to us. It is retained by the ozone of the outer layers of the atmosphere. The small portion that gets through can harm our skin if we do no take cautions when we expose ourselves to the sun for too long. A skin cancer specialist will recommend we should not expose ourselves for too long especially during the summer.

The balance of life
Without living things there is no oxygen, without oxygen there is no ozone, without ozone there are no living things…Life on Earth depends on the balance of many factors that must act in the right measure: with no solar radiation there is no life, but an excess of it could kill everything.

A short history review: Ozone Formation

About 4 billion years ago life started on Earth. However, for many million years there was no life on the land, because of the high amount of radiation from the sun that hit the Earth that made it impossible. The only living things were on the bottom of the oceans, and were mainly seaweeds. At some point, a new kind of seaweed appears, with chlorophyll that start occupying the shallow areas close to the shores. There they get enough light to be able to do photosynthesis and were safe from the excess of solar radiation. For million of years, these seaweeds released oxygen, than ended up in the atmosphere. So, the primitive atmosphere of the Earth began to change, reducing the proportion of carbon dioxide and increasing the oxygen to the levels of our time. From the atmospheric oxygen, ozone started to form, that accumulated in the outer layers of the atmosphere. The ozone prevents harmful solar radiation to go through, and, when the ozone layer had enough thickness, some organisms began living outside the water, on the mainland. It was the beginning of the conquering of the planet. 

The ozone is not an especial or weird substance. The ozone is just oxygen in a tri-atomic molecular form, this means, 3 atoms instead of 2 of the “normal” oxygen molecules. This is the reason ozone is so unstable.

Stay tuned and will explain the Photosynthesis process in a chemical way ;)

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