Overview
Purpose: telling the "why."
Intro: Much more detail. Explain what's about to happen, make predictions, define unknown variables, citations, etc.
Table of physical constants
Data: make it look nice and professional.
Discussion: explain everything from the introduction, but after the experiment occurred. What happened vs what you thought would happen. explain anything that went wrong, possible sources of error.
Conclusion: Tie together with the purpose. Was the purpose of the experiment achieved or not, a brief explanation of why or why not.