Provide and all relevant background information needed to understand the materials or the problem/question. Include explanation of special formulas and vocabulary. Main purpose is to introduce the research by presenting its context or background.
Background information is not a summary of the experiment you are running. It is however a summary of main ideas, concepts, and formulas used to research (run the experiment) including all special vocabulary. You want your audience who reads this section to be able to understand the rest of the lab including all technical information and vocabulary.
Do not use the pronoun "it" and avoid using the first person "I" or "we." In addition, whenever possible, choose active verbs instead of passive ones (ex: use "the study tested" instead of "it was tested by the study" or "I tested in the study").