The Sun has been a revered celestial entity from times immemorial, so much so that primitive civilizations used to worship the Sun as an equivalent to gods and goddesses. The role played by the Sun in sustaining life on earth is indisputable, and indispensable. The impact of the heat of the Sun on human life needs no introductions and discussions. In fact, all the life forms on the earth depend in some way or the other on the Sun’s existence.

Today, school and college academia devotes appropriate attention towards the study of renewable sources of energy. Sun is the most prominent source of ‘clean and green’ fuel in the form of sunlight, which can be further transformed to various energy equivalents. Even at a primary education stage, the concept of greenhouse and heat retention is introduced to students, which is logical enough, considering the fact that ‘green energy’ seems to be the hottest topic of discussion in all quarters of the world. In such a scenario, solar energy and the experiments pertaining to it make a healthy field of knowledge for students and learners.

The most obvious advantage of solar energy based experiments is the fact they can be started right away, as the basic ingredient of such a recipe, i.e. sunlight, is free of cost, and abundantly available. There are many standard solar energy experiments conducted in schools, colleges and universities, all varying in the nature of complexity and the scale of execution. Science fairs conduced in states all over the world play hosts to many intriguing solar energy based experiments and projects. In fact, it is simply mesmerizing to witness the advanced results that researchers and developers have been able to achieve in the field of solar energy based experiments. The results of such experiments have been the base upon which many new age products such as solar cookers, solar heaters and solar panels have been developed.

A very simple solar energy experiment is one based on the trapping of sunlight in a specially designed container, exhibiting the greenhouse effect at a micro scale. All you need to have to get on the way in this experiment is two shoeboxes, and a lot of sunlight! Once you have two similarly sized cardboard boxes, the next step would be to strengthen the walls of the boxes so that they exhibit a greater degree of insulation. But make sure that the walls are equally strong in both the containers. Place aluminum foil on the bases of both the boxes, and paint one of them black from the insides. Once the paint becomes dry, you need to attach plastic coverings on the top of the open boxes. The plastic plays the role of glass in an actual greenhouse. You are all set now to begin the experiment. Place the two containers in an area receiving sufficient sunlight. It is observed that the box with a black base acquires heat much faster than the one without it. And this simple experiment is the base for many remarkable inventions running on solar energy.

Solar cookers are a result of the extension of the above experiment. It consists mainly of a cooking container in the form of a box that is painted black from the insides, for precisely the same reason we did it in the above mentioned experiment. A reflector replaces the plastic covering. This not only provides for efficient concentration of the sunlight onto a small area (thus resulting in enhanced heating) but also retains the heat developed inside the container. By choosing the pan material carefully, we can provide for the prolonged retention of heat inside the container, so that it can be used even in the absence of substantial sunlight. Cast iron is generally used for this purpose. Experimentation with the insulating material is also carried out to determine the best combination for the purpose. Cardboard, newspapers, cloth rags, etc. serve the purpose quite efficiently in an experimental set up. However, in commercially available products, the manufacturers ensure proper insulation material coating and layering. This makes the solar cooker a lot more efficient, as well as aesthetically appealing. Such solar cookers are designed to develop and withstand temperatures as high as 150 degree Celsius. Solar cookers enjoy widespread endorsement in many parts of the world, especially those that are particularly well endowed with sunlight.

The most telling impact of solar energy experimentation has been in the form of the invention of solar cells, which laid the foundation for high end solar energy products such as solar vehicles. In fact, ‘photovoltaics ‘ is a vast study field now, exploring the potential of solar driven electrical appliances and advancing upon the established technologies. Solar cells are generally used in arrays, so that the output current derived out of the system is substantial enough to be utilized in consumer product applications. A small sized array suffices in handling a small device such as a telephone set, but a large array is required to serve the purpose of satisfying the complete household’s electricity needs. Though earlier prototypes of solar panels were incomparably expensive as compared to grid electricity, but ensuing research and experimentation have resulted in remarkable improvements. For instance, environmental interaction used to result in damaging of the solar cell systems, but present day assemblies are manufactured keeping stability and fidelity in mind. Major experimenting countries in the field of photovoltaic appliances are Germany, Japan, USA and Australia. However, United States based firms have conducted advanced experiments as regards the all new thin film technology which allows for the printing of solar cells on an aluminum base, thus cutting down on the costs involved in manufacturing a conventional solar panel.

Apart from the above mentioned hot topics on minds of solar energy enthusiasts, experiments pertaining to solar collectors and heaters are also popular. In Europe, where the winters are particularly severe, a solar heating system becomes an economically and environmentally viable option. This explains the extensive experimentation in heat tapping being conducted in the continent.

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