In this opening paragraph, you should state, in your own words, what this experiment was supposed to accomplish, or what question it was supposed to answer.
Tell, in your own words, what you did. Show that you understand the nature of the experiment. A clearly-labelled diagram may very well be appropriate here. Be sure to use the proper physics terminology.
Attach your data, sample calculations, and results. Write a sentence or two that demonstrate that you know and understand what really happened in your experiment. This will probably be a qualitative statement, but not always.
Write a paragraph discussing, in your own words, what limitations of equipment and/or procedure affected the precision of your results, and by how much. If you were going to repeat this experiment, what would you do that might improve your results? Support your hypotheses, and do not engage in idle speculation.(Reports that use the phrase "human error" will be returned ungraded. Put a little thought into it, please.)
How well did your lab fulfill its purpose? Why do you think so?