In this inquiry investigation, students discover how a given amount of light changes in intensity when the area it shines on changes, and that change in light and heat occurs when the Earth is tilted towards or away from the Sun. Supplies required for the lessons include clipboards, thermometers, graph paper, and flashlights. This is the tenth of 10 inquiry investigations in Threads of Inquiry: Observing the World Around Us. Each lesson includes teacher background information, a narrative that models and describes the inquiry process applied in the lesson, and a hands-on inquiry investigation. Literacy extensions and a non-linguistic pre- and post-assessment are also included.