The purpose of this assessment probe is to elicit students’ ideas about light and shadows. It is designed to find out students’ ideas about how shadows change throughout the day. Observing changes in shadows is a common activity for elementary school students and a good way to build inquiry skills and identify patterns. Middle school students can extend their investigations of shadows to look for seasonal patterns since they understand that the position of the daytime Sun is related to Earth’s rotation and results in the length and position of shadows. High school students use ideas about light reflection to further investigate how shadows are formed, including comparing shadows formed by point sources versus extended sources of light. Teacher notes, standards, assessment, and references are provided. This book selection also includes the Table of Contents, Dedication, Preface, Introduction, and Index.