绿叶鸟网（www.lvyeniao.cn）原创整理的 > 考研英语作文 In science, a theory is a reasonable explanation of observed nts that are related. A theory often involves an imaginary model that s scientists picture the way an observed nt could be produced. A good example of this is found in the kinetic molecular theory, in which gases are pictured as being made up of many all particles that are in constant motion.
A usel theory, in addition to explaining past observations, s to predict nts that have not as yet been observed. After a theory has been publicized, scientists design experiments to test the theory. If observations confirm the scientist's predictions, the theory is supported. If observations do not confirm the predictions, the scientists must search rther. There may be a fault in the experiment, or the theory may have to be revised or rejected.
Science involves imagination and creative thinking as well as collecting information and performing experiments. Facts by themselves are not science. As the mathematician Jules Henri Poincare said, "Science is built with facts just as a house is built with bricks, but a collection of facts cannot be called science any than a pile of bricks can be called a house."
Most scientists start an investigation by finding out what other scientists have learned about a particular problem. After known facts have been gathered, the scientist comes to the part of the investigation that requires considerable imagination. Possible solutions to the problem are formulated. These possible solutions are called hypotheses.
In a way, any hypothesis is a leap into the unknown. It extends the scientist's thinking beyond the known facts. The scientist plans experiments, performs calculations, and makes observations to test hypotheses. Without hypothesis, rther investigation lacks purpose and direction. When hypotheses are confirmed, they are incorporated into theories.
