Science is guided by the vast body of scientific laws which have been established through careful testing by experimentation over the past 300 years. There is no precise "recipe" for doing science. However, the basic premise in science is that natural phenomena have underlying patterns that tend to repeat. Thus a scientist's challenge is to discover the patterns in nature, and to describe the patterns using models which are idealized representations of natural phenomena.

As the diagram below indicates, the scientific process begins by raising a question about a natural phenomenon for which there is no known answer. Presented with a puzzling or a new phenomenon, a scientist first frames a specific question such as "What Causes a Phenomenon?". Next a scientist generates a model to represent the phenomenon, then tests the model through repeated experimentation. Once an acceptable correspondence has been found between the model and the experimental data, the scientist can use the model to answer the question raised. A model can take on many different forms such as a physical representation, a verbal or written description, a drawing, a specific graph or mathmatical expression. All scientific models must be testable, and are considered successful only after validation through experimentation. It is important that you understand the differences between the terms scientific model, experimental data, and natural phenomenon. Why must a scientific model be testable?

Basic process of doing science

The basic premise in science is that knowledge is advanced when a correspondence is found between the model and the observed phenomenon. In the diagram above, the link between the model and the phenomenon actually observed is marked with "??". Why do you think we can never find an exact correspondence between a model and the actual phenomenon?

In creating models, scientists draw on known laws and theories in science, as well as their own intuition or "common sense". Generating a model is a highly creative process. Since it is assumed that you have no prior knowledge of scientific laws, you will begin with only your life experiences (i.e. your "common sense"), plus the observations you make doing experiments in this manual. As the semester progresses, you will build up a body of scientific knowledge based on the models you generate and test. Your scientific reasoning, experimental, and observational skills, as well as your scientific knowledge base will all improve during the course of the semester, provided that you actively participate in the process of doing science. Discussions with other class members and your instructors are essential for building your scientific knowledge base, your reasoning skills and your understanding of the process of doing science.

The foundations of scientific inquiry in the physical sciences rest on developing skills to pose a scientific question, to generate models, to make predictions, to design experiments, to interpret your experimental results, and to judge whether and how to modify your models. The experiments presented in this book are intended to help you develop these skills of scientific inquiry.

Handling Experimental Data and Reporting Results

Role of Your Lab Book
Essentially every scientist maintains some kind of informal journal which describes on-going experiments, plans, results, and personal comments. This informal log is essential in experimental science, because the log provides a detailed documentation of one's daily progress and thinking. Entries in a scientist's Lab Book are personal notes about what was done in an experiment, and what thoughts were on his/her mind each day that the experiment was performed. Sometimes experiments take months to perform and must be repeated with slight variations. The Lab Book serves as an informal scientific journal, and you will be expected to generate one throughout the semester.

Note: A good lab book for ASU PHS110 is the Flexi Comp Lab Book (5x5 Quad ruled, 80 sheets), which is available at the ASU Book Store on campus (#774475, about $3.00).

As a science student, we expect you to develop good reporting habits by keeping a journal of your experiments in your Lab Book, and referring to these notes when writing your formal Lab Reports. Entries in your Lab Book may include any informal information, experimental data, and your personal comments. You should record notes in your Lab Book for all experiments performed in this course during the semester, whether done in the lab, in class or at home. Each entry in a Lab Book should begin with a Date and a Heading. You should develop the habit of summarizing your measurements in Data Tables. Use your Lab Book to jot down calculations and to figure your measurement errors. If you plot graphs using a computer, tape copies of any graphs into your Lab Book. You should keep notes on the progress of each experiment in your Lab Book, and make personal comments when you notice something special or you want to remember a detail. Your Lab Book is your daily record of doing science.

The Lab Report
Your Lab Report, on the other hand, is a more formal report which summarizes very concisely only the most essential details of the experiment and the results. The Lab Report is more like a journal article that a scientist would publish as a permanent record, to officially report the experimental results to other members of the scientific community. The formal or official report for any scientific experiment is usually in the form of an article which is published in a scientific journal. After a scientist has performed an experiment several times to check that the results are repeatable, the results are interpreted in terms of a scientific model and reported to the scientific community. Usually the report is in the form of a paper that summarizes the model, the experiment, the results and the conclusions. This paper is generally submitted to a scientific journal for publication. Publication of any scientific article in a journal is preceded by anonymous "peer" reviews of the article by other scientists who have expertise in the same specific subject area. After peer review, the article may be accepted for publication (usually after revision), and upon publication of the journal, the scientific results become available to the entire scientific community.

The analogue of the scientist's published journal article for a student doing science is the Lab Report. Criteria used to grade a student's Lab Report are similar to those used to review a scientist's manuscript before it is accepted for publication. Such criteria include: 1) Clarity and conciseness (Diagrams, figures and tables should be used to summarize experiment details and results wherever possible.), and 2) Clear but brief descriptions of the purpose, model, experimental set-up, results and conclusions. Your conclusions should be substantiated by explaining the reasoning which led you to those conclusions.

Any Lab Report should be a concise summary of the essential elements of the experiment, and should be polished and well organized (by producing several drafts before being considered finished).

Guidelines for Written Lab Reports
1. Lab Reports generally should not exceed two typewritten pages (single-spaced, 12 point font, one inch margins). Graphs, figures and tables are not included in this page count. All Lab Reports are due one week after you perform the experiment, and should be turned in to your Lab Instructor at the beginning of next week's lab.

Note: Check your course syllabus for the number of points that are deducted for any late Lab Reports. Late reports will not be accepted up to one week after the due date. Lab Reports later than one week past the due date will not be accepted.

2. Follow the additional guidelines given at the end of each Experiment.

3. Your report should include five parts:

I. Title, Date, Your Name, Your Lab Partners' Names.

II. Summary Paragraph: A few brief statements giving the purpose of the experiment, the model you tested, your results and conclusions.

III. Experiment: A description of your procedure referring to a clearly labeled sketch of the equipment used.

IV. Data and Analysis: Include all experimental data in table or graph form. Label all tables and graphs clearly (titles, column headings, graph axes), and always include measuring units (e.g. m/s). If you fit functions to your data, be sure to state on the graph the mathematical function that you used to model your data.

V. Discussion: Most important part of your Lab Report. Discuss your interpretation of the data in terms of your model and address the original question posed in the experiment. Your interpretations should explain the meaning of the slopes of any straight lines to your graphs. Be sure to explain your reasoning in assessing how well your model represents your data. You should always end your discussion with a statement of your conclusions.