In science, a theory is a reasonable explanation of observed events that are related. A theory often involves an imaginary model that helps scientists picture the way an observed event 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 small particles that are in constant motion. A useful theory, in addition to explaining past observations, helps to predict events that have not as yet been observed. After a theory has been publicized, scientists design experiments to test the theory. If observations confirm the scientists predictions, the theory is supported. If observations do not confirm the predictions, the scientists must search further. 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 more 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 scientists thinking beyond the known facts. The scientist plans experiments, performs calculations, and makes observations to test hypotheses. Without hypothesis, further investigation lacks purpose and direction. When hypotheses are confirmed, they are incorporated into theories.
最后一个月如何备战SAT
阶梯英语歌谣:你是我的阳光
阶梯英语歌谣:那是我家
SAT阅读高分心得:每天投入,配合技巧
阶梯英语歌谣:在客厅
阶梯英语歌谣:写说拼擦
阶梯英语歌谣:我准备好了
阶梯英语歌谣:今天来聚会吧
解析SAT考试认识的误区
阶梯英语歌谣:你和我
阶梯英语歌谣:我爱我家
阶梯英语歌谣:对不起,我们迟到了
阶梯英语歌谣:盒子里有什么?
阶梯英语歌谣:猜猜看
看SAT大神如何拿下2340高分
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SAT备考心态调整
亲历香港SAT考试
阶梯英语歌谣:大拇指在哪里?
阶梯英语歌谣:15只小鸟
阶梯英语歌谣:美好的一天
SAT临考前一月复习方案
阶梯英语歌谣:是的,我认识!不,我不认识!
阶梯英语歌谣:在卧室里
阶梯英语歌谣:去打球吧
SAT考试2300分的网友经验分享
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考SAT必知的20条Tips
SAT高分经验全面分享
阶梯英语歌谣:我们一起去花园吧!
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