SelfGuide

SECTION THREE : Introduction

Establishing a context for the lab

Step 1: Begin the Introduction with 1 or 2 sentences clearly stating what scientific concept the lab is about. Then finish the paragraph by writing down details about this concept relevant to the lab that you can find in the lab manual, textbook, class notes, handouts, etc . . . Revise your answer so that it includes only the information that relates specifically to this lab. If you have a lot of information, make two paragraphs. Note any citations you use here for including in the References section of your report.

More Help:

• If you are having trouble writing a good opening sentence for the lab report, you can say something like: "This laboratory experiment focuses on X…"; "This laboratory experiment is about X…" ; "This lab is designed to help students learn about, observe, or investigate, X…." Or begin with a definition of the scientific concept: "X is a theory that…."
• Once you have your opening sentence, you are ready to complete the opening paragraph by telling what you know about the scientific concept. The point is to show your lab instructor that you have a good grasp of the scientific concept. Revise the rest of Question 1 by:
  • Focusing it so that it contains information about the concept that is most clearly related to the lab procedure (not everything there is to know about the concept)
  • Incorporating additional relevant information about the concept you may have learned since doing the PreLab.
  • Changing it so that the scientific concept is appropriate to the lab (this would apply if all or parts of what you wrote about the scientific concept in the PreLab are wrong for this lab).
• If you have a lot to say about the scientific concept, use more than one paragraph.
• This part of the Introduction is typically written in present tense.

For more advanced labs:

If you are writing a lab report that is more like a full scientific paper, you may need to do more research using the Internet and library. With your teacher's guidance, you should search the recent scientific literature to find other research in this area of study. Summarize that research in a paragraph or so, stating what the general findings have been and using those findings to describe the current knowledge in the area (such a "review of the literature" is typical of scientific journal articles). This summary should come after your initial sentence about the scientific concept. For help with citing references, go to Citations and References.

Step 2: Write the main objectives of the lab--the specific actions you took in the lab, such as measure, analyze, test--in sentence form. Then complete the paragraph by describing how the achievement of these objectives helped you learn about the scientific concept of the lab.

More Help:

• Objectives are typically actions you are being asked to perform for the lab. Often the objectives are listed in the lab manual. Writing the objectives of the lab in your own words demonstrates your understanding of what you were supposed to accomplish in the lab. With most labs, you should be able to do this in 1 or 2 sentences. You can begin by saying something like: "The main objectives of this lab were to…"; "In this lab we were asked to…." This will be the beginning of the paragraph.
• Continue the paragraph by addressing the purpose of the lab. This is where you make the all-important link between what you do in the lab (the objectives) and the purpose for doing the lab: to learn something about the scientific concept of the lab. Read over the objectives again. In what way do you think that doing the experiment, accomplishing the objectives, helped you learn about the scientific concept? You can start by saying something like this: "The objectives of this lab enabled me to learn about X by…"; "Performing these objectives helped me to understand X by…."
• This part of the Introduction is usually all in past tense.

Step 3: State your hypothesis, what you thought the outcome of the experiment would be before you did it. This will be the first sentence of the hypothesis paragraph. To write a scientific hypothesis, you first need to identify the independent and dependent variables in the experiment.

More Help:

• Write your hypothesis so that it is clear, such as: "The hypothesis for this lab was…"; "My hypothesis was…"; "We predicted that…"; "I hypothesized that…."
• Often hypotheses are stated in terms of variables, the elements that the experiment focuses on. Be sure to use your original hypothesis, what you thought the outcomes of the experiment before you performed the experiment.
• A variable is what is measured or manipulated in an experiment. Variables provide the means by which scientists structure their observations. Identifying the variables in an experiment provides a solid understanding of the experiment and what the key findings in the experiment are going to be.
• To identify the variables, read the lab procedure described in the lab manual. Determine what you will be measuring and what you will be manipulating for each measurement. The value(s) you are manipulating is called the independent variable (also known as the "manipulated variable") and the value(s) you are observing/recording is called the dependent variable (also known as the "response variable"). Write down the dependent and independent variables.
• In more advanced labs, you may have multiple variables, more than one independent and dependent variable.

  Look back over all the stages of the experiment:

• How do these variables relate to each other?
• Are there more than one independent and/or dependent variable being recorded through the various stages of the experiment?
• How does the data being recorded in one stage help you in the proceeding stages?
• If there are more than one independent and dependent variable, which one(s) will be used to answer the question being asked in the lab? That is, which variables will be used to formulate your hypothesis?
  

Step 4: Continue the paragraph you began with a hypothesis by explaining how you used your understanding of the scientific concept of the lab to arrive at your hypothesis.

More Help:

• As you are explaining the reasoning you used to come to your hypothesis, be sure to make a direct connection between the hypothesis and the scientific concept of the lab. Rewrite it so that your reader can clearly see how you used your understanding of the scientific concept of the lab to make a prediction about the outcome of the lab. Refer to what you said in the first paragraph of the Introduction.
• One way to make your explanation clear is to use words that show causal links: because, since, due to the fact that, as a result, therefore, consequently, etc. For example, Since X happens in order to maximize energy, we hypothesized that . . .
• If your explanation is relatively long, use more than one paragraph.