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.
贵州省贵阳市2014高考英语(新人教版)一轮阅读训练(5)附答案
【北京专用】2014届高考英语一轮复习方案课时作业:必修2 Unit 1 Cultural relics
【北京专用】2014届高考英语一轮复习方案课时作业:必修4 Unit 3 A taste of English humour
安徽省淮南市2014高考英语一轮单项选择及文章训练(19)及答案
【北京专用】2014届高考英语一轮复习方案课时作业:选修8 Unit 2 Cloning
【北京专用】2014届高考英语一轮复习方案课时作业:必修4 Unit 4 Body language
【北京专用】2014届高考英语一轮复习方案课时作业:必修2 Unit 5 Music
【北京专用】2014届高考英语一轮复习方案课时作业:必修5 Unit 1 Great scientists
安徽省淮南市2014高考英语一轮单项选择及文章训练(9)及答案
【北京专用】2014届高考英语一轮复习方案课时作业:选修7 Unit 3 Under the sea
【北京专用】2014届高考英语一轮复习方案课时作业:必修5 Unit 2 The United Kingdom
贵州省贵阳市2014高考英语(新人教版)一轮阅读训练(8)附答案
学会分享 Learn to Share
【北京专用】2014届高考英语一轮复习方案课时作业:必修4 Unit 2 Working the land
安徽省淮南市2014高考英语一轮单项选择及文章训练(2)及答案
【北京专用】2014届高考英语一轮复习方案课时作业:必修4 Unit 5 Theme parks
【北京专用】2014届高考英语一轮复习方案课时作业:选修8 Unit 4 Pygmalion
【北京专用】2014届高考英语一轮复习方案课时作业:选修7 Unit 2 Robots
安徽省淮南市2014高考英语一轮单项选择及文章训练(17)及答案
【北京专用】2014届高考英语一轮复习方案课时作业:必修3 Unit 1 Festivals around the world
安徽省淮南市2014高考英语一轮单项选择及文章训练(11)及答案
【北京专用】2014届高考英语一轮复习方案课时作业:选修6 Unit 2 Poems
安徽省淮南市2014高考英语一轮单项选择及文章训练(5)及答案
【北京专用】2014届高考英语一轮复习方案课时作业:必修5 Unit 4 Making the news
安徽省淮南市2014高考英语一轮单项选择及文章训练(8)及答案
安徽省淮南市2014高考英语一轮单项选择及文章训练(12)及答案
安徽省淮南市2014高考英语一轮单项选择及文章训练(10)及答案
安徽省淮南市2014高考英语一轮单项选择及文章训练(16)及答案
【北京专用】2014届高考英语一轮复习方案课时作业:选修7 Unit 4 Sharing
【北京专用】2014届高考英语一轮复习方案课时作业:必修3 Unit 4 Astronomy:the science of the stars