Physics is an experimental science. The theoretical concepts and relationships introduced in the lecture part of the course describe the general nature and behavior of real phenomena. They were, appropriately, discovered by (or inducted from) careful observation and thoughtful analysis of actual experiments. Genuine understanding entails being able to relate the abstract ideas to the particular facts to which they correspond.
The premise of the scientific method is that (observation of) nature is the ultimate judge of the truth of any physical theory. Indeed, experiments designed to prove certain ideas have often ended up showing them to be wrong. Consequently, all physical concepts must be verified experimentally if they are to be accepted as representing laws of nature.
Accordingly, the introductory physics laboratories have the following purposes and goals:
1. To provide an experimental foundation for the theoretical concepts introduced in the lectures. It is important that students have an opportunity to verify some of the ideas for themselves.
2. To familiarize students with experimental apparatus, the scientific method, and methods of data analysis so that they will have some idea of the inductive process by which the ideas were originated. To teach how to make careful experimental observations and how to think about and draw conclusions from such data.
3. To introduce the methods used for estimating and dealing with experimental uncertainties, including simple ideas in probability theory and the distinctions between random (statistical) and systematic "errors." This is essential in understanding what valid conclusions can be deduced from experimental data and that, properly obtained, these conclusions are valid, notwithstanding the uncertainty of the data.
4. To learn how to write a technical report which communicates scientific information in a clear and concise manner.
5. To introduce new concepts and techniques which have a wide application in experimental science, but have not been introduced in the standard courses. These may require that the student consult additional textbooks.
The laboratory is not a contest whose object is to get the "right answer." The purpose is to learn how to gain knowledge by looking at reality, not an attempt to make reality conform to preconceptions. The important thing is to learn how to be observant, to really see what happens, and to deal with this information with the strictest integrity. And to understand, or learn to understand, the meaning of what happens.
Even if you get results totally at variance with theory (as may happen due to a mistake, or a systematic uncertainty) you will get a high grade if you report it honestly and demonstrate that you understand what you did and how your results occurred. (If you have trouble interpreting your results, contact your TA for help.) On the other hand, if you get perfect agreement with theory by faking your data you will fail.
Practical ability to do experiments and analyze data is usually acquired through practice and experience. Practice is very important in learning any new discipline; such as, for example, a new language. A good lecture may be very helpful but not fully useful without actual practice. In experimental science, practice involves solving many problems (i.e. homework) and performing a variety of experiments (i.e. labs). Practice is essential to being able to make the connection between theory and experience.