I don’t suppose very many of my usual readers take The Guardian at home, but in general I have found its science reporting to be better than the other newspapers. They still fall prey to press releases from Universities and industry, publishing reports of scientific findings uncritically and without checking their sources, but usually I feel confident that the topics will be discussed sensibly. I recently read this article about the world’s largest artificial sun. It is part of a project trying to find a way of splitting hydrogen from water in an efficient fashion.
Hydrogen is the most abundant element in the Universe but there is almost no freely available hydrogen on Earth. It is in water and it makes up about 60% of the atoms in living things. If it could be produced in large quantities it would make a very useful fuel. At present, it takes more energy to extract it than is recovered when it is used. Since the only waste product of using it is water it would be a fantastic response to climate change if we could harness it as a fuel.
One renewable form of energy is solar power. This can be in the form of photovoltaic cells that directly turn the Sun’s light into electricity. Another system is a solar furnace. This concentrates the Sun’s energy onto a single spot to boil water, produce steam and drive a turbine. A group of researchers in Germany is working on a way to focus the light with even more efficiency. To this end, they have built themselves an artificial sun to test out their new lenses and mirrors. The ‘sun’ is an array of light bulbs (known as Synlight) that produces light about ten thousand times as bright as natural sunlight. This can then be concentrated onto a spot to produce a temperature of about three thousand degrees Celsius. Currently it consumes a huge quantity of electricity but the hope is that, with the right mirrors and lenses, natural light could replace the artificial Sun.
What is different here is that instead of merely trying to boil the water, they are hoping to split it into hydrogen and oxygen. The hydrogen could then be used directly or converted into another fuel. One idea is to combine it with carbon monoxide, which can be produced from biofuels in a sustainable way, to make artificial kerosene as an environmentally friendly aviation fuel. Although this would still burn to make carbon dioxide, the process overall would be carbon neutral because the carbon monoxide used would be extracted from carbon in the atmosphere.
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Questions…
- What do we call chemicals that are simple compounds of carbon and hydrogen?
- What two substances are produced when these compounds combust in a plentiful supply of oxygen?
- Describe a chemical test for either of these products.
- The light bulbs used are xenon tubes normally found in cinema projectors. To which group of elements does xenon belong?
- Water can be split using electricity directly. What name is given to this process?
- If hydrogen is the most abundant element in the Universe, what is the second most abundant and where is it produced?
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