Shadows are a phenomenon we experience every day; however, we may not have noticed how they change over a year. In this unit, we will try to understand how and why these changes occur. First, we will examine secondary data (graphs of shadow length) and try to understand patterns of change in shadow length over the year. Based on our understanding, we will make some predictions about our own shadow, which we will verify through observation and measurement. Finally, through an explanation of the apparent celestial motion of the sun, we will understand why shadows change over the year.