Sample summary

The main points in the text below can be written in a shorter, summary form for inclusion in your own writing. Points about the summary:

■ it is about one third of the length of the original (88 words, compared to 273 in the original

■ the number of sentences has been reduced from 16 to 4

■ the information has been compressed into these 4 sentences by

* cutting out less important information, e.g. examples

* reducing a whole clause or sentence to a phrase

* by using more subordinate clauses

* linking ideas by simple use of commas

Original text

Solar power is energy generated from the sun. Many electronic devices, such as watches and calculators, can use the sun's energy directly to provide the power they need. Light energy from the sun changes the electrical conducting properties of the silicon crystals, and a tiny electric current starts to flow. This system is called a solar cell. Although solar cells used on earth do not provide much power, satellites in space run on the same principle. They get many times more energy because they are closer to the sun. In the future, workers in space may build huge power stations from solar cells many kilometers wide. The electricity generated could be beamed down as microwaves and then converted back into electricity. Most of the solar power that we use today is based on a much simpler principle than the silicon solar cell. Solar panels on the roofs of houses heat water directly for bathing and central heating systems. The industrial version of the solar panel is the solar furnace, in which huge, curved solar panels, together with a system of mirrors, concentrate a large amount of solar energy onto a small area. The heat energy makes steam for generating electricity. Solar power is clean, renewable, non-polluting and does not damage the environment. It is potentially one of the more important sources of energy in the world. A major disadvantage of solar energy is that the amount of energy generated depends on the season, the part of the world and the weather on a particular day. Another disadvantage is that the raw materials for solar panels, such as glass and aluminium, are quite expensive.

from Dr Trisha Greenhalgh (1994) Environment Today Harlow, Longman

Sample summary

Dr Greenhalgh explains how solar power works in two ways. Light from the sun can generate a tiny current in silicon crystals, creating a solar cell, which is used to run space satellites and in the future could provide electricity from space power stations. Solar panels, or the larger industrial solar furnace, generate heat directly through concentrating solar energy in a small area. Solar power is renewable, non-polluting and potentially an important energy source, but its value is limited by weather, region and the cost of raw materials.

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