This document provides guidance on creating an excellent Internal Assessment (IA) for the IB Physics course. The IA involves a 10-hour scientific investigation and 6-12 page write-up. It counts for 20% of the overall IB grade. Acceptable formats include hands-on labs, spreadsheet analysis, database extraction, or simulations. The IA is evaluated based on personal engagement, exploration, analysis, evaluation, and communication. Sample investigation topics are provided such as studying the effect of string tension on fundamental frequency or sugar concentration on refractive index. Students are instructed to submit their sample IA in two weeks.