The introduction of the lab is where you are explaining what experiment you are about to do and what you already know about the topics that are involved. It should be written before the experiment is done and even before a hypothesis is made. (We may not always have time to do this before the lab, so if you are writing it afterward keep this in mind.)
What Goes Into Your Intro:
-The purpose of the lab: What are you trying to accomplish? (If given by the teacher you can copy directly)
-Background information: What do we already know about the main ideas involved in the investigation? How does our prior knowledge lead to the purpose of the lab? Include a summary of any information that someone would need to know in order to understand the lab purpose, your hypothesis and your interpretation of the data. (You do not need to explain common sense ideas. A good rule of thumb would be to imagine you are explaining the lab to a freshman in high school, they have some general knowledge but have never taken a physics class.) This is also where you would explain any research you did prior to the experiment. (Be sure to cite properly.)
-An outline of the experiment you are doing: A broad explanation of how you plan do arrive at your results, and what specifically you will be looking for in your results (how will you know if you have achieved the lab purpose?). This is also where you would discuss independent and dependent variables if applicable. (no need to get into specifics, measurement details are covered in the procedure)
Common Mistakes:
-Trying to include every vocabulary word for the section as a main idea. Just because it is in the same section of the curriculum does not mean it is part of the focus of the lab.
-Thinking that defining vocabulary is a discussion of the background information. It is possible (although usually not the case) that the definition is everything you know about a topic, however you must make a connection to the experiment that you are doing.
-Writing about what you think will happen. This belongs in the hypothesis section.
-Making a separate "Purpose" section.
Next Section: Hypothesis